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Astrophotography

Why You Should Start with a Refractor Telescope

|Telescopes|12 Comments

If you’re getting started in deep-sky astrophotography, I believe that a compact apochromatic (APO) refractor telescope is the best possible choice.

A compact APO refractor is portable and lightweight, making it a smoother transition from the camera lenses you may be used to. In fact, in many ways, a high-quality apochromat is very much like a telephoto lens. 

If you’re interested in photographing nebulae and large galaxies in the night sky through a telescope, this article should shed some light on the decision-making process ahead of you. 

astrophotography with a refractor telescope

My first refractor telescope was an 80mm Explore Scientific apochromatic triplet. 

Introduction

Throughout the past 8 years of deep-sky astrophotography, I’ve made lots of mistakes. In the beginning stages, I made critical errors in selecting and setting up equipment. 

From the beginning, my goal was to capture deep-sky images of nebulae and galaxies. This type of astrophotography requires the most advanced equipment and demands a careful setup routine. 

The type of telescope you choose early on can have a dramatic impact on the complexity of your deep-sky astrophotography setup. In my experience, a compact, wide-field refractor offers an improved user experience over the other telescope types during the acquisition stages of astrophotography.

For example, I began taking my first deep-space images with a reflector telescope. If I could go back and I do it all over again, I would have chosen a compact, wide-field refractor to start astrophotography with. 

setting up telescope

These days, I use a refractor telescope for 90% of my astrophotography. 

I am not saying that there is anything wrong with starting your astrophotography journey with a Schmidt-Cassegrain Telescope (SCT) or Newtonian Reflector, but I believe you will have some additional challenges to overcome early on. 

No matter what type of photography experience you have going in, deep-sky astrophotography through a telescope will have a number of challenges to overcome early on.

This includes understanding how to polar align an equatorial mount, how to focus your camera on a faint deep-sky object, and how to attach your camera to the telescope. two out of the three challenges become more difficult if you’re not using a wide-field refractor to start.

The statement above is not theoretical, I personally experienced these frustrating moments in my backyard years ago. I should have started with a compact refractor telescope. 

deep-sky astrophotography

A recent photo of NGC 7822 captured using a color camera and a 100mm refractor.

I Should Have Started with a Refractor

I often see newcomers to deep-sky astrophotography starting with a telescope that will make an already-challenging hobby even more difficult. I went through this experience personally, and this is what happened. 

My first astrophotography telescope was a Meade LXD55 6″ Schmidt-Newtonian. I purchased this reflector telescope from a local camera store second-hand, for a great price. 

At the time, I had very little knowledge of telescope-types, optical designs, or astronomy in general. I took the advice of the salesman at the store, and he assured me that “this telescope can be used for astrophotography”.

comparing a reflector to a refractor

The telescope I started taking pictures of space with.

First off, he was right. It could certainly be used for astrophotography, and I even found astrophotography images online taken by others using this particular model.

The problem was, this type of telescope presented some pretty daunting challenges to overcome. My long term love for astrophotography was at stake, as a poor experience could potentially sour me on this new adventure. 

Thankfully, I kept a positive mindset throughout the process despite having limited knowledge (and limited funds). 

This was my First Astrophotography Telescope

astrophotography telescope setup

My first telescope for Astrophotography was NOT a refractor, and it presented some challenges.

I mounted the Meade LXD55 SN6 to a Celestron CG-5 (Advanced Series GT) computerized telescope mount. The GoTo tracking mount was my biggest investment in the hobby early on, and looking back the mount was performed surprisingly well. 

A Schmidt-Newtonian is a promising instrument for astro-imagers. The corrector plate helps you collect images with less coma than a traditional reflector design.

Essentially it’s a catadioptric telescope that combines elements from both the Schmidt camera and the Newtonian reflector. A spherical primary mirror is combined with a Schmidt corrector plate to correct the image. 

It looks capable enough in the picture, so what’s wrong with starting your astrophotography adventure with a Newtonian Reflector, Schmidt-Cassegrain, or a Ritchey–Chrétien? 

Some would argue that there is nothing wrong with any of these choices, but here’s why it wasn’t a good fit for me:

It was Heavy and Difficult to Balance

It wasn’t a bad telescope, and I even managed to collect my first-ever deep-sky image with it. I really had no idea what I was doing at this point, and was absolutely thrilled to finally captured a tracked deep-sky object in the night sky. 

The problem with this old Meade telescope was that it was not a great type of telescope to start with. Looking back, a compact refractor telescope would have made my life a lot easier at the time. 

For starters, it was rather heavy and difficult to balance. It was at the maximum payload capacity of my equatorial mount (Celestron CG-5), and I even had to use some “custom” counterweights to achieve balance.

In the astrophotography world, you never want to have your telescope rig reach the weight limits of your telescope mount. This puts extra stress on the equatorial drive system and often results in poor tracking. 

first picture of Andromeda

My first picture of M31 (Andromeda) using the Meade reflector telescope (July 2011).

It Had Too Much Magnification

In my opinion, the telescope had a little too much focal-length as well. Extra magnification can be great for pulling in small targets, but it’s also more demanding on aspects such as pointing accuracy, tracking, and focus. 

Prime-focus astrophotography involves attaching your camera directly to the focuser of the telescope, with no additional eyepieces or lenses between them. That means that the native focal length of the telescope decides the field-of-view (FOV) and scale of the objects you shoot. 

The SC6 had a focal length of approximately 762mm, which could be considered to be a “mid-range” focal length. For comparison, my William Optics Zenithstar 73 refractor has a focal length of 430mm. 

I really shouldn’t complain about the 762mm focal length (FL) of the 6″ Meade, some amateur astrophotographers start out with an 8″ SCT with a demanding 2000mm+ FL. (I think I would have given up!)

The Focuser was Loose and Difficult to Secure

As newcomers will tell you, achieving a tight focus on your deep-sky subject can be challenging early on (Here are some tips).  It’s hard enough to find the optimal focus distance without worrying about the focuser “slipping” out of position on its own. 

Like a traditional Newtonian telescope, the focuser is placed near the front of the optical tube to collect light from the secondary mirror. This creates a challenging situation in terms of balance, especially when using a heavy, full-frame DSLR camera. 

The weight of my camera would put stress on the objective end of the optical tube. Despite using the locking screw, the DSLR would eventually fall downwards into the focuser as the night progressed. I constantly had to re-adjust focus after 4-5 images.

In general, I find reflector telescopes to be more challenging to focus than a refractor, and that was certainly the case with this F/5 Schmidt-Newt.

Start with a Compact, Wide-field Refractor

I’m not saying that a refractor telescope is the only way to go, but I think you’ll find that the astrophotography community generally agrees with me on this one. To be more specific, an apochromatic refractor is best. 

Refracting telescopes use lenses, not a mirror, to deliver crisp views through the eyepiece, and high contrast, well-corrected color images with your camera. 

In late 2011, early 2012, I invested in an Explore Scientific ED80 Triplet APO refractor. The reason I call this an “investment” is that not only did this telescope reward with me with my best images to date, but quality glass hold their value quite well.

ED80

Below, is an old photo of my 80mm refractor telescope on a Celestron CG-5 equatorial telescope mount. The difference between the images I was collecting with the Schmidt-Newt and the APO refractor was night and day. 

The stars were small and well-corrected (all of the colors came to a focus at once), and I no longer dealt with coma, reflections, and dramatic vignetting. 

Explore Scientific ED80

My first refractor telescope was an Explore Scientific ED80. 

Another advantage this telescope had was the field of view. Being a beginner, I had my heart set on capturing some of the most iconic deep-sky objects like the Orion Nebula, Andromeda Galaxy, and the Pleiades star cluster. 

The focal length of this telescope (480mm) was a perfect fit for all of these targets. I didn’t need to worry about creating a mosaic to fit the entire object in the frame. Images like this were the reason I got into astrophotography in the first place.

Finding targets in the night sky became a lot easier thanks to the forgivingly wide field of view. Even if the pointing accuracy of my computerized equatorial telescope mount was off, I could usually find my intended deep-sky target within the field-of-view of my first slew.

best telescopes for astrophotography

See my list of recommended refractors for astrophotography.

The first summer (2012) with my Explore Scientific 80mm refractor telescope was an exciting one. I captured several amazing photos of deep-sky objects with my Canon EOS Rebel Xsi DSLR. 

The most exhilarating photo came in July of 2012 when I attempted to photograph the Andromeda Galaxy with my 80mm refractor and stock Canon DSLR. The image was a monumental improvement over my attempt the previous summer. I was especially thrilled at the clarity of the image and natural star colors recorded. 

astrobackyard first andromeda

My first successful image of the Andromeda Galaxy (July, 2012). 

The Perfect Astrophotography Telescope

A high-quality doublet or triplet apochromatic refractor is capable of producing sharp, flat, well-corrected images. Almost all types of telescopes are capable of impressive astrophotography images, but some make you work a lot harder for it. 

For example, a Newtonian Reflector presents an advantageous light-gathering ability and an affordable price-per-aperture. However, Newtonians require regular collimation and adjustments to avoid coma and perform at their best.

An apochromatic refractor will perform much better in terms of photography than its less expensive achromat counterpart. 

The objective lens (consisting of 2 or more pieces of glass) of an apochromatic refractor is designed to focus light to the same point, and correct chromatic aberration. As you can see in the diagram below, an apochromatic objective focuses different wavelengths of light closer to the same point than an achromat does.

apochromatic vs achromatic

“The strict definition of apochromatism is having three wavelengths of light focusing to the same point.  This normally requires a third lens element in the objective.  The normal configuration is a positive, low-dispersion crown, combined with two high-dispersion flints, one negative and one positive.  The lenses can be cemented, air-spaced, or a combination thereof.” Starizona.

For a technical description of how a refractor telescope works, and the refractive index of certain mediums, check out this informative article

Pros and Cons of a Compact APO Refractor Telescope

There are some pros and cons to using a compact refractor telescope for astrophotography, and here they are:

Pros:

  • You can mount them to modest, entry-level equatorial mounts
  • Refractors are compact and lightweight compared to other telescope designs
  • The focusers are solid and easy to focus
  • They offer a similar experience to a high-end telephoto camera lens
  • The image quality potential for astrophotography is exceptional
  • Refractors do not require regular collimation or optical adjustments
  • They offer a forgiving, wide field-of-view

Sky-Watcher Star Adventurer Pro Review

You can mount a small refractor on a portable tracking mount like the Sky-Watcher Star Adventurer.

Minus:

  • They are the most expensive telescope type (price per aperture)
  • They are not well-suited for high-magnification planetary imaging
  • The apertures are often too small to observe faint deep sky objects
  • Galaxies and smaller DSO’s need 1000mm+ for an up-close view

My favorite astrophotos of all time were all taken using a refractor telescope. From my first experiences with the Explore Scientific ED80 to the massive Sky-Watcher Esprit 150 Super APO, refractors are my number one choice for astrophotography. 

The image below shows a William Optics Zenithstar 73 refractor mounted to a modest Sky-Watcher HEQ5 GoTo telescope mount. My DSLR camera is attached to the focuser of the telescope for deep-sky imaging at 430mm.

This entire ensemble can be lifted up and moved around the yard on a moment’s notice, so I usually keep the entire imaging system ready to go in the garage.

A setup like this is also refreshingly easy to travel with. It does not take up very much space in my vehicle and can be re-assembled quickly. 

telescope equipment

A portable deep-sky imaging setup with a 73mm refractor telescope. 

This versatile and reliable rig does not come at the expense of performance either. A small setup like this is capable of producing incredible astrophotography images using a DSLR/Mirrorless camera or a dedicated astronomy camera.

The photo below shows the image captured using the telescope setup pictured above in my video titled “Taking a Picture of the Andromeda Galaxy“.

This image includes 67 x 120-second exposures using a Canon EOS 60Da. 

Andromeda Galaxy

My latest version of the Andromeda Galaxy using a DSLR and a small refractor telescope. 

My Newtonian Reflector Collects Dust

In 2014, I decided to purchase an 8″ Newtonian Reflection, the Orion 8″ F/3.9 Astrograph Reflector. The idea was to add some light gathering power and a little more focal length at an affordable price. 

However, I had become used to the quick and setup time of my 80mm refractor, and balancing the big optical tube on my Sky-Watcher HEQ5 mount was time-consuming.

Also, I had to regularly collimate the tube before each and every imaging session. Perhaps the telescope was perfectly collimated before I attached my camera, but I always had to make sure before spending a night collecting images. 

I did manage to capture some impressive images with this setup, but surprisingly, the added aperture did not add the extra “punch” to my images I was looking for. In the end, this telescope was a lot more effort, for very little (if any) benefit to my astrophotography.

reflector vs. refractor for astrophotography

I do not use my 8″ Newtonian Reflector very much these days.

What Size and Brand Should You Buy?

I’ve used refractor telescopes with an aperture of 51mm, all the way up to 150mm. Smaller, compact APO’s are much more practical and affordable, yet do not sacrifice as much performance as you may think.

For example, the image of the Lagoon Nebula and Trifid Nebula region of Sagittarius was captured with a miniature (51mm aperture) William Optics RedCat APO and a DSLR camera. This quadruplet refractor weighs just 3.2 pounds and can fit in your carry-on bag

wide field deep sky astrophotography

Nebulae in Sagittarius using a William Optics RedCat 51 APO. 

Nearly every telescope manufacturer builds refractor telescopes, and I’ve had the opportunity to try many of them. I’ve had wonderful experiences using apochromatic refractors from Explore Scientific, William Optics, Meade, and Sky-Watcher.

William Optics compact doublets are very popular and rather affordable considering the optics used in their designs. The Zenithstar 73 APO is one such example, and a telescope I have personally taken a lot of beautiful images with.

The Sky-Watcher Esprit line of refractors is a step up, with the Esprit 100 Super APO (Triplet) being my most used refractor of all time. These telescopes are expensive and quickly grow in price as aperture is added. 

sky-watcher telescope

Setting up the Sky-Watcher Esprit 100 refractor telescope in the backyard. 

When choosing a refractor telescope for astrophotography, ensure that it is an apochromatic optical design, not an achromat. Also, ensure that the optical tube includes a robust, 10-1 speed focuser that can lock into position when needed. 

You’ll also need to confirm that the mounting hardware will allow you to mount the telescope to your equatorial mount, and add additional accessories such as a guide scope and camera for autoguiding. 

Make sure you invest in the appropriate field flattener for your refractor, as this extra glass lens will help flatten the field of view to the very edges of your picture.

Final Thoughts

If your astrophotography interests lie in taking images of nebulae and large galaxies, an apochromatic refractor should be your number one choice of telescope.

This category of deep-sky objects includes some of the most iconic wonders in space, and you could spend a lifetime capturing them.

Not only is an APO refractor a perfect fit in terms of focal length (native magnification), but the images with your DSLR/Mirrorless or dedicated astronomy camera will be extremely sharp and well-corrected.

If your looking to photograph the planets, a compact refractor is not for you. Smaller targets such as planets and many galaxies are not a good fit for a wide-field refractor.

But if you’re a fan of quick set up time, consistent results, and wide-field nebulae like the ones below, you simply cannot beat an APO refractor.

soul nebula

The Soul Nebula in Cassiopeia using a William Optics Zenithstar 73 APO. 

Pleiades

The Soul Nebula in Cassiopeia using a William Optics RedCat 51 APO. 

Recommended Refractors for Astrophotography

The following list of apochromatic refractor telescopes have all produced exceptional results for me personally, so I feel comfortable recommending them. They are all compact, wide-field instruments capable of producing images like the ones shared in this post. 

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The Canon EOS Ra Announced

|Camera|17 Comments

On November 5, 2019, the Canon EOS Ra was announced and is now available for pre-order at various retailers including B&H. This is a 30.3 MP full-frame mirrorless camera designed specifically for astrophotography. 

The Canon EOS Ra shares nearly all aspects of the EOS R camera body, with 2 key differences for astrophotography. Increased sensitivity to the 656nm (h-alpha) emission line, and a 30X live view focus mode.

For a niche hobby like astrophotography, the Canon EOS Ra has sure attracted a lot of attention from the photography world. I pleaded my case to my contact at Canon for an early unit to review but was not successful in my efforts (and I’m not even bitter about it).

Thankfully, some new and exciting example images have already surfaced from those that were granted early access to this camera body, and from Canon themselves.

canon astrophotography camera

In this article, I’ve put together all of the information I can find about the EOS Ra, and included the limited number of example images shared thus far. To see the full slideshow of images shared by Canon with this camera, see this article by Todd Vorenkamp of B&H. 

The Canon EOS Ra

The CMOS sensor found inside of the Canon EOS Ra is 4x more sensitive to the hydrogen-alpha wavelength, which is extremely useful for astrophotography. As many of you know, some of the absolute best deep-sky nebula in the night emit a strong red signal in the 656 nm wavelength.

Historically, amateur astrophotographers that wanted to collect the powerful deep reds found in many emission nebulae with their generic DSLR cameras had to remove the stock internal IR cut filter. This is called modifying your camera for astrophotography and is offered professional from several vendors. 

Canon began offering “pre-modified” DSLR cameras from the factory for astrophotography use in 2005 with the revolutionary EOS 20Da. The Canon EOS 60Da followed in 2012, and now, the mirrorless EOS Ra in 2019. 

The first example photos I saw using the Canon EOS Ra were courtesy of fellow Canadian, Alan Dyer. He posted the following example images using the EOS Ra on Twitter late Tuesday night:

Canon EOS Ra astrophotography examples

Images shot using the Canon EOS Ra by Alan Dyer (Read his review here)

This camera is aimed at landscape astrophotography enthusiasts (such as wide-angle Milky Way photography), and deep-sky imagers using an equatorial telescope mount. The mirrorless design of the EOS Ra is a massive change from Canon’s last astrophotography camera. Not only is it a different style of camera mechanically, but it also accepts Canon RF Lenses

The 30.3 MP full-frame CMOS sensor found inside of the RA is beneficial for amateur astrophotographers that use wide-angle lenses. If you own Canon EF mount lenses as I do, you’ll need to buy the EF-mount adapter to attach your lens. 

I must admit, it will be hard to justify purchasing the “a” version of the Canon EOS R for many multi-discipline photographers that take photos in the daytime as well as night. This camera has some impressive specs for photography and videography including shooting 4K at 30p with Canon Log. 

I have always shot my videos with Canon DSLR cameras (most recently the Canon EOS 6D Mark II), and am a little confused as to how I would fully utilize the video features of the EOS Ra. As Canon has stated numerous times about their “a-series” cameras, they are not suitable for daytime photography. In my tests with the 60Da, the colors are slightly off and create unappealing daytime images without serious adjustments in post. 

Canon EOS Ra

Increased Sensitivity to Hydrogen-Alpha

If you are new to Canon’s astrophotography camera line-up, you may be wondering what the difference between the EOS R and Ra is. 

The reason this version of the camera has an “a” in the name is simply due to the specialized infrared-cutting filter that sits in front of the CMOS sensor. Canon lists that this change allows a transmission in the hydrogen-alpha (Hα) wavelength that is approximately 4 times greater than a regular Canon EOS R camera. 

The example images from Canon USA illustrate this capability on the North America Nebula. I found it very interesting to note that Canon’s engineers report an even greater sensitivity to Hα in the EOS Ra than previously achieved in the 20Da and 60Da camera bodies. 

EOS Ra vs. R

Essentially, the Canon EOS Ra is a modified version of the EOS R for amateur astrophotographers that want to collect more signal in the important Hα emission line. For the same reason I invested in the Canon 60Da, I like the idea of Canon handling the astro-modification and not voiding the warranty with a third-party service. 

The infrared-cutting filter (positioned immediately in front of the CMOS imaging sensor) is modified to permit approximately 4x as much transmission of hydrogen-alpha rays at the 656nm wavelength, vs. standard EOS R cameras. This modification allows much higher transmission of deep red infrared rays emitted by nebulae, without requiring any other specialized optics or accessories.

30X Live-View Magnification

If you’ve experienced what it is like to focus a camera at night, you’ll know how important the live-view zoom feature is. The best way to focus your camera lens or telescope with a DSLR or mirrorless camera attached is to zoom-in on a bright star and magnify it. Traditionally, this would be at a magnification of 10X, but Canon has upped the ante. 

The Ra features Canon’s first-ever 30x magnification, and it can be done on both the LCD screen and viewfinder. Because the EOS Ra is a mirrorless camera system, the electronic eye-level viewfinder is able to provide the magnification feature. As a DSLR shooter, this would feel very strange to me and I doubt it would be a useful as the much larger LCD screen.

Speaking of the LCD screen on the back of the camera, it’s a vari-angle design. This is extremely useful for astrophotographers, as we regularly point the camera in all sorts of awkward angles. 

ISO Performance

Any amateur astrophotographer with experience using DSLR cameras will tell you that the amount of noise in your image will increase as you bump up the ISO. This creates a challenging trade-off, as we often want to collect as much light in a single exposure as possible. 

However, modern cameras have got a lot better and keeping noise at bay using higher ISO settings, and the Canon EOS Ra is no exception. 

In this video from B&H, the host states:

“high ISO noise is extremely well-controlled, particularly at the high ISO’s that are common in astrophotography”

It’s impossible to tell exactly how well “controlled” the noise is from the example photo shared (below). The same vague statement was said about the Canon 60Da, and I found it to be true when shooting at an aggressive ISO 6400 on warm nights in the summer. 

sample photo

Sample image from Canon USA. Canon EF 400mm F/2.8L IS III USM Lens.

Canon EOS Ra Core Specifications

  • Format: Full-Frame
  • Sensor Type: CMOS
  • Sensor Size: 36 x 24mm
  • Pixel Size: 5.36 microns
  • Max. Resolution: 6720 x 4480
  • ISO Sensitivity: 100 – 40000
  • Lens Mount: Canon RF
  • Video Modes: 4K up to 30p, HD up to 60p
  • Memory Card: Single SD
  • Weight: 1.45 lbs.

The following video released by B&H and Canon USA covers many of the core specifications of the Ra, and what separates it from a regular mirrorless camera. I appreciate the improved battery performance of this camera over the previous models. Canon states that the battery will last for 7 hours of bulb exposure time, although I expect this to time to diminish on a cold night. 

Canon’s Astrophotography Timeline:

The EOS Ra is the third installment (not the 4th, as I have seen a non-existent “6Da” reported) in Canon’s line of dedicated cameras for astrophotography.

  • Canon EOS 20Da (2005)
  • Canon EOS 60Da (2012)
  • Canon EOS Ra (2019)

Let’s not forget Nikon’s contribution to the astrophotography community. The Nikon D810A is a fantastic DSLR for astrophotography and was the first full-frame camera body built specifically for night photography. I would not be surprised if Nikon (and Sony) release dedicated mirrorless camera bodies for astrophotography in the future.

Just like in the daytime photography world, the number of lenses you own in a particular brand is a big deciding factor when upgrading your camera body. 

Final Thoughts

The Canon EOS Ra is clearly a big step up from the last astrophotography camera released, the 60Da. More megapixels, bigger pixel size, better ISO performance, more sensitive to Hα, a better viewfinder, a mirrorless body – so what’s not to love? 

In my eyes, there are two reasons why an amateur astrophotographer will look elsewhere for their next camera. The first one is that there are many practical dedicated (CMOS) astronomy cameras available now, ones that offer cooling and sensitive monochrome sensors. 

The other is that modifying an older Canon DSLR is still a very practical way to collect impressive astrophotography images for a fraction of the price.

RF lens mount

The Ra accepts Canon RF lenses (full-frame mirrorless)

However, I think there are many people that enjoy the familiarity of a DSLR/mirrorless camera system. If you travel a lot for astrophotography, a mirrorless camera and lens are much more practical than a dedicated astronomy camera and software to run it. 

Another great point that has been brought to my attention about this camera is the file types created and their compatibility with stacking software.

The Canon mirrorless cameras create CR3 file format images, which are currently not supported in software such as DeepSkyStacker (at the time of writing). This might be a great reason to hold off on the EOS Ra until these applications catch up with the technology.

Another big change is the opportunity to use filters between the camera body and lens via the Canon Drop-In Filter Mount Adapter (EF-EOS R). Daytime photographers use this attractive feature for drop-in variable ND filters, but perhaps the astronomy companies will begin to manufacturer astrophotography filters for this configuration. 

I think this would big a much better option over the clip-in style filters currently offered for full-frame DSLR’s.

EOS R Ef mount adapter

The Canon EF-EOS R Drop-In Filter Mount Adapter.

The big question is, will I be ordering the Canon EOS Ra for astrophotography in the backyard? Probably.

At the time of writing, the price tag for the body only is $2,499 USD, and it will be released on December 19, 2019. I order my photographer gear on Amazon almost exclusively, and the package offered by Canon includes a battery charger, strap, and a few extras.

whats included

I am interested in testing the camera from both a hobbyist perspective and to provide useful information to amateur astrophotographers looking to purchase this camera. The interesting thing is, if I do purchase the Ra, it will be my first mirrorless camera.

As an ambassador of the hobby, I feel obligated to share my experiences with the latest official astrophotography camera from my favorite brand, and yes, you can go ahead and label me a Canon fanboy.

Helpful Resources:

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The Rokinon 135mm F/2 was Built for Astrophotography

|Camera Lenses|11 Comments

In this post, I’ll explain why I think the Rokinon 135mm F/2 is the perfect addition to an arsenal of astrophotography lenses. 

Deep sky astrophotography is often associated with a camera and telescope, but the truth is there are a lot of great camera lenses for astrophotography out there. In the past, I’ve covered a number of different lenses, from the Rokinon 14mm F/2.8 to the Canon EF 300mm F/4L.

As you know, camera lenses come in varying focal lengths, apertures, and optical quality. Astrophotography is one of the ultimate tests of lens quality, as long exposure photography of deep-sky objects in space can highlight issues that are hidden during daytime photography.

In this post, I’ll share my results using an affordable prime telephoto lens for astrophotography, the Rokinon 135mm F/2.0 ED UMC. The version I have has the mount for Canon EOS camera bodies, but there are several different lens mounts available on Amazon.

Rokinon 135 F2 ED UMC

My Canon EOS 60Da with the Rokinon 135mm F/2.0 mounted to a Fornax Mounts LighTrack II.

This lens is available for several camera mounts, including Nikon, Sony, Pentax, Samsung, and Fuji. I purchased this lens for the purposes of wide-field deep sky astrophotography from my light polluted backyard (shown below), and when traveling to a dark sky site.

Taking images at this focal length from the city will swell issues with gradients, especially when shooting towards the “light dome”. For this reason, a combination of a good light pollution filter, and the use of flat calibration frames are recommended. Before I go any further, I’d like to share a photo from Gabriel Millou of the Andromeda Galaxy using a Canon 1300D.

Samyang 135mm F/2

The Andromeda Galaxy using the Rokinon 135mm F/2.0 ED UMC lens. 

To see even more example photos using the Rokinon 135mm lens (or Samyang branded version), go ahead a perform a search on Astrobin or Flickr, with the appropriate filter. I think you’ll find that this lens is behind some of the most amazing wide-field astrophotography images online!

The Rokinon 135mm F/2 ED UMC

The full name of this lens is the Rokinon 135mm F/2 ED UMC, with “ED” standing for extra-low dispersion, and UMC referring to the “ultra multi-coated” optics. This is a fully manual lens, meaning that it does not have autofocus, and you must manually select the f-stop using the aperture ring at the base of the lens.

Manually focusing a lens for astrophotography is nothing new, but the manual aperture ring adjustments may feel a little strange at first. 

Rokinon lenses are made in Korea, and so is the Samyang variation. The full extent of the relationship between Rokinon and Samyang is unknown to me, but the packaging on my lens says “Technology by Samyang Optics”. I typically shoot with Canon lenses, but the potential for low light photography (whether that’s astrophotography or the ability to film at dusk) caught my interest.

Rokinon 135mm F/2 lens specifications

The diameter of the lens is 77mm, with a non-rotating filter mount on the objective lens. The lens hood is removable (and reversible), which makes packing the Rokinon 135mm away into the included lens pouch possible. The presentation and hands-on look and feel of the 135mm F/2 lens is impressive considering the reasonable price of this lens. 

The aperture range of this lens is F/2 to F/22, with 9 diaphragm blades (aperture blades) that work in harmony to set your f-stop. The aperture ring is marked with each f-stop, and you need to manually click through F/2 – F/22 and watch the blades do their work. It’s actually kind of neat to watch!

I ordered this lens on Amazon, utilizing my Amazon Prime membership. The lens arrived next day, less than 24 hours after I hit the order button. The lens came in a handsome box, with core specifications and a lens construction diagram printed on the side. The Rokinon 135mm F/2.0 includes a lens hood, lens pouch, front and rear lens caps, and a 1-year Rokinon manufacturer warranty.

First Impressions

Overall, the lens feels very solid and well constructed. The finish and texture of the Rokinon 135mm F/2 is a step up from the 14mm F/2.8 I ordered a few years ago. 

The spec sheet for the Rokinon 135mm F/2 boasts a number of qualities, with the ones listed below being the most important when it comes to night photography and astro. Based on my handful of experiences with this lens in the backyard, I have found these traits to hold true.

  • Low-Light Performance
  • Low Chromatic Aberration
  • Low Flare and Ghosting

The image below highlights the creative freedom this lens provides. To fit the Heart and Soul Nebulae in a single frame requires an extremely wide field of view (compared to the magnification of most telescopes). The 135mm focal length is absolutely perfect for the Heart and Soul Nebulae if you’re using a crop sensor DSLR camera.

The image shown below covers 4.96 x 5.98 degrees in the constellation Cassiopeia. The images were collected using a Canon EOS Rebel T3i camera riding on a Fornax Mounts LighTrack II

heart and soul nebula

The Heart and Soul Nebulae captured using a DSLR and the Rokinon 135mm lens. 

The Rokinon website lists this lens as being useful for portraiture photography, and most telephoto applications. The shallow depth of field present at its maximum aperture does indeed create a pleasing bokeh. 

The lens hood is not petal-shaped, which is great news for those using this lens for astrophotography. The flat lens hood design allows you to easily take flat frames with the Rokinon 135mm using the white t-shirt method or using a flat panel. 

I should mention that I have only tested this full-frame lens using my astrophotography DSLR’s, all of which are crop-sensor camera bodies. This creates an effective focal length of roughly 200mm, a useful magnification for a wide variety of astro-imaging scenarios. 

I am no stranger to the full manual control of this lens, for both aperture and focus. The Rokinon 14mm F/2.8 was the first lens I had ever used like this, and these aspects do not hinder the astrophotography experience whatsoever. 

A Full Frame, Prime Lens

The Rokinon 135mm F2.0 is considered to be a full-frame lens because it can accommodate a full-frame image sensor with its 18.8-degree angle of view. In this review, however, I am using the lens on a crop sensor (APS-C) Canon EOS 60Da, which puts the field of view at 12.4 degrees.

“Prime” means that this lens is fixed at 135mm, it is not a zoom lens that allows for focal length adjustments. Prime lenses are typically lighter as they do not need the additional glass and mechanics required to zoom at varying magnifications. 

Generally, prime lenses have a reputation for being slightly sharper, and I have found that to be true whether I am shooting a nebula or a Scarlet Tanager. 

The optical design includes one extra-low dispersion (ED) lens element to control chromatic aberration, and “ultra multi-coatings” (UMC) to both improve light transmission and reduce flare. 

lens focal length

The flat lens hood is great for taking flat frames after a night of astrophotography.

Low Light Capabilities at F/2.0

The F/2.0 maximum aperture of the Rokinon 135mm lens offers a chance to collect a serious amount of signal in a single shot. This allows for less aggressive camera settings for night photography such as using a lower ISO setting and shorter exposure. 

Of course, when it comes to astrophotography, this can create some challenges as well. Focusing a “wide open” F/2 lens is demanding of the optics, especially on a field of stars in the night sky. 

One way to combat potential soft images and chasing perfect focus all night is to stop the lens down to F/2.8 or even F/4. Your images have a chance at remaining sharper once critical focus has been achieved, but now you have lost the extra light-gathering power you wanted. It’s a trade-off, and one that seems to surface time and time again in this hobby.

Although typically unused in astrophotography, I did get a chance to see the beautiful bokeh this lens creates when shooting at F/2. The aesthetic quality of the blur in the out-of-focus parts of the image are buttery smooth and soft. 

lens for astrophotography

What I Really Like

Although this lens feels solid, it is rather light when compared to a telescope. When coupled with my Canon DSLR camera, the entire system weighs just over 3 pounds. That means that it doesn’t require a robust equatorial telescope mount as a larger, heavier telephoto lens would. 

A camera tracker (or “star tracker“) is necessary for long exposure deep-sky astrophotography, but a compact model such as the iOptron SkyTracker or Sky-Watcher Star Adventurer will do just fine. 

This lens has a long focus adjustment ring, with great tension. The focuser adjustment rotates roughly 270 degrees, meaning fine-tuning on a bright star is more precise. You’ll never have to worry about losing your position just by touching the lens, but you can always tape the position down to be sure. 

The Rokinon 135mm F/2.0 ED UMC is one of the most affordable and practical lenses for astrophotography on the market. Sure, the “Nifty 50” is an incredible value (and a LOT cheaper), but the 135mm puts you within range of some of the best astrophotography targets in the night sky. 

I’ve spent a handful of nights testing this lens in my Bortle Scale Class 6/7 backyard, and my results live up to the hype it gets in terms of astrophotography performance.

Comparable Lenses (Chart)

Lens Comparison

BrandFocal LengthMaximum AperturePrice
Canon135mmF/2.0$999 (B & H)
Nikon135mmF/2.0$1,391 (B & H)
Sony135mmF/1.8$1,898 (B & H)
Rokinon135mmF/2.0$499 (Amazon)

Lens Comparison

Over the years, I’ve shot deep-sky targets at varying focal lengths from 50mm to over 1000mm. The closest I’ve been to the 135mm range is 105mm on my Canon 24-105 zoom.

Not only does the Rokinon 135 add additional reach, but I can also now shoot at F/2, instead of F/4 on the Canon. Below, are a few examples of astrophotography images I’ve taken with lenses of varying focal lengths. 

As you can see, the magnification of the lens used will dictate the type of projects you shoot.

lens comparison

  1. The Great Rift of the Milky Way – Rokinon 14mm F/2.8 
  2. Mars meets Pleiades – Canon EF 24-104mm F/4L
  3. Wide-field Sadr Region – Rokinon 135mm F/2.0
  4. The Carina Nebula – William Optics RedCat 51

So what’s so great about shooting at 135mm anyway?

The RedCat is deeper at 250mm, and after that, you’re into 300-400mm territory which pulls galaxies and nebulae even closer. Why take a step back from 250 to sit between the RedCat and the 24-105?

It’s all about framing.

Image Scale at 135mm

From the moment I reviewed the first sub-exposure on the display screen of my camera, I feel in love with the mid-range magnification of a 135mm lens. My first shot was a section of the constellation Sagittarius that included the Lagoon Nebula, and Trifid Nebula.

If you want to preview the image field you can expect with a particular camera sensor and lens combination, Stellarium features a useful tool. The Image Sensor Frame tool lets you enter in the size of your camera sensor, and focal length of your lens (or telescope) to display a frame over the star map.

This is a very practical way to plan your next astrophotography project, and especially handy when using a wide field lens like the Rokinon 135mm F/2. 

astrophotography scale

You can use Stellarium to preview the image scale with the 135mm lens and your DSLR. 

At 135mm, you can get really creative about the object or objects you shoot and where you position them within the frame.

And because you can shoot between F/2 and F/4, plenty of light reaches the sensor in a relatively short exposure. This has several advantages from less demanding tracking accuracy, to being able to use a lower ISO setting.

The Downsides of this Lens

Now, I have to admit that up to this point, it sounds a little too good to be true. The downsides of this configuration are that shooting wide open can make focusing difficult.

The focuser adjustment ring on the Rokinon 135mm F/2 is excellent, but fine-tuning your critical focus on a bright star at F/2 will take some trial and error to get right. You may need to refocus your subject as the temperature changes throughout the night. 

You may need to stop down to control star bloat, and that’s exactly what I’ve done with this 135. I’ve set the f-stop to F/2.8, to sharpen up the stars a bit. In fact, in my test shots, I noticed that the red channel was a little softer than green and blue. To remedy this, I reduced the star size in post, and I started shooting at F/4 to really tighten things up.

Also, as creative as the wide field 135mm focal length is, it’s not practical for smaller DSO’s and most galaxies. Stick to Andromeda, and skip the Whirlpool.

I have heard others mention that this lens has a “plasticky” build quality, but I believe this aspect has been improved. The model I use feels solid and the barrel is constructed with metal.

The lens is not weather-sealed, so you definitely don’t want to leave your camera and lens (and your tracking mount!) in the rain. There’s no image stabilization on the Rokinon 135mm F/2 either, but that’s a non-issue for amateur astrophotographers. 

135mm lens

The North America Nebula captured using the 135mm lens with a clip-in Ha filter.

Recommend Astrophotography Targets for this Lens

Large emission nebulae like the California Nebula (pictured below) are a great choice for this focal length. The image below was captured using a DSLR and 135mm lens on the Sky-Watcher Star Adventurer mount. 

California Nebula at 135mm

The California Nebula. Canon EOS 60Da with the Rokinon 135mm F/2 lens.

I’ve captured a lot of deep-sky astrophotography targets from the northern hemisphere, but I’m usually in too deep to capture an entire region of space at once. Here is a short list of great astrophotography targets to shoot at 135mm with this lens:

  • Orion’s Belt (Including the Horsehead Nebula, Orion Nebula, and M78
  • The Witch Head Nebula including Rigel in Orion (Careful with star reflection!)
  • The Rosette Nebula and Surrounding Nebulosity
  • Cygnus, including the North America Nebula and Pelican Nebula
  • The Sadr Region in Cygnus including the Crescent Nebula
  • The California Nebula in Perseus
  • The Blue Horsehead Nebula in Scorpius
  • The Rho Ophiuchi Cloud Complex in the constellation Ophiuchus

Below, is an incredible example of the types of projects possible with the Rokinon 135mm F/2.0 lens. The following image was captured by Eric Cauble using the Samyang branded version of this lens. 

astrophotography example image

The Sadr Region in Cygnus, including the Crescent Nebula by Eric Cauble. 

Since Eric was so generous to share his images with me, I had to include his photo of the Rho Ophiuchi cloud complex as well. This photo was captured with the Samyang 135mm F/2 lens using a UV/IR cut filter and a QHY168C dedicated astronomy camera.

Rho Ophiuchi Cloud Complex

The Rho Ophiuchi Cloud Complex by Eric Cauble using the Samyang 135mm F/2 lens. See the full-size version on Astrobin

Final Thoughts

With an effective focal length of roughly 216mm when coupled with a Canon crop sensor body, the field of view is nearly identical to the one you’d find on a full-frame camera with a 200mm telephoto lens. That’s quite a jump from 135mm, so the camera body you use with this lens may change the types of targets you shoot. 

I can’t wait to try this lens out during the winter months on some wide-field targets in Orion. The colder temperatures will make DSLR astrophotography much more practical, and there are plenty of great targets to choose from.

During the frigid months of winter, my motivation to spend over an hour setting up my complete deep-sky imaging rig dwindles. However, stepping outside to polar align a small star tracker and attach a DSLR and lens is quick and painless. 

In these situations, a portable, wide-field imaging rig wins.

Star parties or dark sky excursions are another great time to use a camera lens in place of the telescope. Not only does it let you travel light, but impressive wide field projects are often more successful when captured under a dark sky. 

For those of you that like to “pixel-peep”, have a look at the single image frame captured using the Rokinon 135mm F/2.0 ED UMC at F/4. The image is a 90-second exposure at ISO 400 using a Canon EOS 60Da. The inset picture is a magnified view of the bottom right corner of the frame. 

star test

A single, 90-second exposure using the Rokinon 135mm F/2.0 ED UMC at F/4. 

I hope that this post has provided some practical insight into a popular camera lens for astrophotography. If experience has taught me anything, it’s that the practical, pain-free equipment that gets the most use under the stars. 

This lens is available on Amazon for most camera bodies. Make sure to select your camera mount when checking the price (Check current price). If you have pictures taken using the Rokinon 135mm F/2 lens, please feel free to share your results in the comments section (links to Astrobin, Flickr or your personal gallery are fine). 

List of Compatible Cameras (Mounts)

  • Canon
  • Sony E
  • Fuji X
  • Nikon AE
  • Samsung NX
  • Pentax K
  • Sony A
  • Micro 4/3

Complete Lens Specifications (Canon)

  • Model: 135M-C
  • MSRP: $599
  • UPC: 0-84438-76410-9
  • Focal Length: 135mm
  • Maximum Aperture: F2.0
  • Coverage: Full Frame (FX)
  • Optical Construction: 11 Glass elements in 7 Groups
  • Aperture Range: F2.0 to F22
  • Diaphragm Blades: 9
  • Coating: Ultra Multi-Coating
  • Minimum Focusing Distance: 2.6ft (0.8m)
  • Filter Size: 77mm
  • Lens Hood: Removable
  • Maximum Diameter: 3.2” (82mm)
  • Weight: 29.20oz (830g)
  • Length: 4.80” (122.1mm)

lens construction

Download the User Manual

Helpful Resources:

 

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Sky-Watcher EQ6-R Pro Review

|Equipment|24 Comments

The Sky-Watcher EQ6-R Pro is a computerized equatorial telescope mount with GoTo capabilities. This equatorial (EQ) mount is capable of providing precise, accurate tracking of the night sky, and is suitable for long-exposure astrophotography. 

The core specifications of this equatorial mount include having a built-in ST-4 autoguider port, a payload capacity of 44 pounds, and a SynScan computer hand controller with an extensive database of objects. 

I have been using the Sky-Watcher EQ6-R Pro telescope mount since October 2018, and have used it to capture several deep sky images of nebulae, galaxies, and star clusters in space. In this post, I’ll share some of my favorite features of this EQ mount that I have experienced over several imaging sessions in the backyard.

Sky-Watcher EQ6-R Pro Review

The Veil Nebula captured using the EQ6-R Pro telescope setup shown on the right.

Whether you already own the EQ6-R Pro and are looking to tap into more of its features, or are trying to decide which equatorial mount is best for your visual observation or astrophotography goals, this article should offer up some useful input from someone who’s been in your shoes. 

Related Video: My first run with the Sky-Watcher EQ6-R Pro in the backyard

Sky-Watcher EQ6-R Pro telescope mount

Sky-Watcher EQ6-R Pro Review

Before we dive into some of the interesting features you may not have known about, here is an overview of exactly what the “EQ6” is capable of. As a preface, it’s worth noting that I use this mount for astrophotography exclusively, and I am in the northern hemisphere.

For those in the southern hemisphere, the process is very similar all around, aside from polar aligning the mount with the south celestial pole (SCP).

Before stepping up to the EQ6-R, I used a number of intermediate level astrophotography mounts, including the slightly smaller HEQ5 Pro SynScan model. 

Sky-Watcher EQ6-R Pro

The Basics

The EQ6-R Pro includes a SynScan hand controller with an LCD display that gives you control it’s features and basic functions. The left and right keys on the keypad control the Right Ascension (RA) axis, while the up and down arrows are used to control the Declination (DEC) axis. 

You can control the slew speed by selecting the RATE shortcut button (2) on the keypad, as it is useful to make large movements at a high speed, and subtle adjustments using a slow speed. The Sky-Watcher EQ6-R Pro has 10 slew speeds for complete control over the movement of each axis. 

Before powering up the EQ6-R, your telescope should be in the home position. This means that the EQ head is leveled on the tripod, and the RA axis is pointed towards the north celestial pole (NCP). The counterweight should be at its lowest position, and the telescope should be pointing towards the NCP.  You can then turn on the mount and select the operation mode. 

For those interested in astrophotography, you will only ever want to use the mount in EQ mode. 

Iris Nebula

The Iris Nebula in Cepheus captured using the setup shown on this page.

With the RA and DEC clutches locked, and counterweight(s) attached, you can mount your telescope on top of the EQ head. This is accomplished by fastening the mounting plate of your telescope to the saddle, which accepts both D and V-style mounting plates.

Getting Started

Once the SynScan system has initialized, you can enter in the geographic coordinates of your observing site.

This involves entering the latitude and longitude coordinates of your current location using the cursor on the LCD display and the keypad. Then, you will enter your current time zone, which for me, happens to be UTC -4 in southern Ontario. 

You can also enter in your current elevation, which is used for atmospheric refraction compensation (generally, the higher your elevation, the better). Next is setting the current date and time, and whether you are currently on daylight savings time.  

Once all of these important details have been entered (so the mount understands what is available in the sky from your location), you reach the mount alignment process, with the “Begin Alignment” dialog served up on the LCD screen. 

SynScan Hand Controller

The SynScan Hand Controller set to EQ Mode. 

Use the “Park” Feature

This simple, yet useful feature automatically aligns your telescope mount in both axes at the beginning of your imaging session. It is not exclusive to the EQ6-R Pro, yet it is easy to miss if you don’t follow the instructions in the manual on your first few runs. 

This feature is located under the “Utility Function” menu and asks you to turn off the mount after the park position has been confirmed. The next time you turn the mount on, you will see a dialog on the LCD display asking if you would like to start from the park position.

This is a handy feature that I did not personally take advantage of for the first few months of ownership with the mount. It is nice to confirm the home position when setting up, especially before beginning your polar alignment process.

The EQ6-R is Easy to Polar Align

Whether you use the built-in polar scope with the illuminated reticle or use a QHY PoleMaster device, polar aligning the EQ6-R is a breeze. 

This largely due to the fact that the EQ6-6 includes large, Alt/Az adjustment bolts with comfortable handles. Fine-tuning the polar axis of this equatorial telescope mount is possible thanks to these convenient controls.

The built-in polar finder scope with illuminated reticle allows you to accurately polar align the mount without the need for additional software or accessories. You can either use a third-party mobile app like “Polar Finder” to find out the current position of Polaris, or simply use the information displayed on the SynScan hand controller. 

The SynScan hand controller displays the position of Polaris in polar scopes field of view (FOV). You need to imagine that the large circle in the FOV of the polar scope as a clock’s face with 12:00 sitting at the top.

Then, it’s simply a matter of adjusting the Alt/Az bolts of the mount to place Polaris in the “HH:MM” position provided.

Using a PoleMaster with the EQ6-R

If you don’t like getting underneath the polar scope for a real-time view of the NCP or SCP, the QHY PoleMaster is a great option. This electronic polar scope uses a small camera to display the region surrounding the north (or south) celestial pole. 

Using the live feed through the camera, you can fine-tune your Alt/Az adjustments in a very precise manner. The PoleMaster requires the appropriate adapter (this is the one you need) to fasten it to the polar axis.

QHY PoleMaster Adapter

Fastening the PoleMaster to the EQ6-R using the necessary adapter.

You Can Improve the Alignment Accuracy

Before running a star alignment routine, make sure that your telescope is well balanced, and that there are no loose cables that could get caught and snag on the mount. 

The alignment routine involves choosing a bright, named star from the database and centering it in your telescope eyepiece or camera. The LCD screen displays “Choose 1st Star”, at which point you can cycle through the list to find a star that is not blocked by any obstructions from your location, and press enter.

A word of caution here, once you hit enter, the mount will start to slew to the object immediately. 

From here, it’s a matter of using the arrow buttons on the keypad to center the star. Remember, you can change the slew speed at any time by pushing the “Rate” button and setting the value higher or lower. It is often useful to leverage a finder scope on your telescope when slewing to your first alignment star, as it has a much wider field of view than your primary telescope and makes finder the first star easier. 

When running through a star alignment routine, it is important to consistently center the alignment star in the eyepiece or camera’s FOV. It is beneficial to use a reticle eyepiece with a small FOV. Personally, I use the camera’s FOV and center the star on my DSLR display screen (with grid enabled), or with a cross-hair overlay in my camera control software (Astro Photography Tool).

You can run a 1,2, or 3-star alignment to improve the pointing accuracy of the telescope. This is very important when it comes to photographing deep-sky objects that are nearly invisible until a long exposure image is collected. 

Tulip Nebula

The Tulip Nebula in Cygnus using the EQ6-R Pro mount for tracking.

Avoid Errors due to Mechanical Backlash

You can improve your alignment accuracy by avoiding errors due to mechanical backlash. Backlash is present in all equatorial telescope mounts, and does not affect your observing enjoyment, or your long exposure images when autoguiding is employed.

To avoid introducing alignment error caused by backlash, center the alignment star ending with an UP and RIGHT directions from the keypad. If you overshoot the star using this method, use LEFT and DOWN to bring the star back down the FOV and try again.

Computerized Telescope Mount

The Stepper Motors are Quiet

If you haven’t used this particular mount first hand, you may be wondering what the EQ6-R sounds like while it is slewing. I have heard many astrophotography mounts over the years, and this one is impressively quiet. 

This mount uses stepper motors with a 1.8° step angle and 64 micro steps driven. This technical design aspect results in a quieter mount than on using servo motors.

This means that even at the maximum slew speed (9X), the mount emits a modest hum that will not wake up your neighbors. While the telescope mount is tracking, it is completely silent. It’s only when you move the RA or DEC axis at top speed that you hear a noise.

Compared to other equatorial telescope mounts I have used, the audible sound the EQ6-R Pro makes is more than acceptable. When you are partaking in a hobby that takes place (alone) outside at night, avoiding loud or unusual noises when possible is always a good idea.

In contrast, the Celestron CGX-L computerized mount is noticeably loud while slewing at top speed. If this mount is being used in a closed observatory, it’s not an issue. However, I set up my equipment in a city neighborhood backyard. Depending on the time of night, I hesitate slewing to a new target because of this trait. 

The Autoguiding Performance is Impressive

The Sky-Watcher EQ6-R Pro delivers impressive results when the built-in autoguider port is leveraged. Over the years I have maximized the tracking capabilities of my astrophotography mounts by using an auxiliary guide scope and camera to autoguide using free software called PHD2 guiding

The EQ6-R Pro allows you to set change the default auto guide speed of the mount of 0.5X to 0.75X or 1.0X in the setup menu.  

I have experimented using a guiding rate of 1.0X , and saw little improvement to my guiding graph in PHD2 guiding over the default speed of 0.5X. The point is, you have the option of adjusting this setting if the need calls for it, and it’s a feature I’ve only recently tapped into on the EQ6-R Pro.

For a real-life example of the autoguiding performance you can expect with this mount, have a look at the screenshot below. The guiding graph shows that my total RMS error is 0.63″. Generally, a total RMS error of under 1-second means that you can expect pinpoint stars in your long exposure images.

EQ6-R autoguiding graph

My autoguiding graph in PHD2 guiding using the Sky-Watcher EQ6-R Pro SynScan mount. 

The Mount is Heavier Than it Looks

When it comes to equatorial mounts for astrophotography, being heavy is a good thing. However, I think some people that receive their EQ6-R for the first time may be a little surprised at how heavy the EQ6-R actually is (I was).

The weight of the EQ head is 38 lbs on it’s own, and the tripod adds another 16.5 lbs. Add in two 11-lb counterweights, and you’ve got a telescope rig that weighs 76.6 pounds, and is not going anywhere for a while.

Luckily, the EQ head includes a useful carry handle that I have certainly put to good use. Also, the supplied counterweight bar is retractable, which makes transporting the mount out the door of my garage a little easier. 

mount specifications

I used to carry my Sky-Watcher HEQ5 Pro SynScan around the yard with the telescope and counterweight attached. It was heavy and awkward, but manageable.

This is not possible with the EQ6-R, which is understandable considering the increased payload capacity (44-lbs) of the mount. To transport the Sky-Watcher EQ6-R from my detached garage to the yard, I must remove the counterweights and the telescope first.

It’s possible to lift the tripod with the EQ head attached (54.5 lbs), but this is likely too heavy for most folks. The good news is, this heavy profile means that accidentally bumping the polar alignment out of position by kicking a tripod leg is unlikely. Smaller, ultra-portable mounts like the iOptron SkyGuider Pro do not share this quality. 

You Don’t Need to “Mod” the Mount

If you’re a tinkerer, I get it. It may be tempting to you to open up the EQ mount head and take a look. I would advise against this personally, as you may do more harm than good.

I’ve seen a number of posts and videos discussing “belt-mods” and “hyper-tuning” Sky-Watcher NEQ6 and EQ6-R mounts. Personally, I wouldn’t recommend opening up the mount in hopes of tweaking performance, even if the underlying mechanics are straightforward to you.

In my experience, the Sky-Watcher EQ6-R can track accurately for 10-minute exposures (or longer) without any re-greasing or modifications to the worm gears when autoguiding is leveraged.

I suggest spending the time to get your balance and polar alignment spot-on before blaming the mount for bad tracking. It’s easy to get caught up in scrutinizing the mechanical backlash and periodic error present in the mount.

If you do dive into these advanced adjustments, you better be mechanically minded and ready to invest a “minimum of four hours” for a typical belt modification. 

astrophotography telescope

The EQ6-R with a Sky-Watcher Esprit 100 ED APO attached.

The SynScan Hand Controller gives you Extensive Options

The included SynScan hand controller includes an impressive 42,000+ object database, with almost every possible target you could ever want to observe or photograph.

The Messier object list gets a lot of use for amateur astronomers in the Northern Hemisphere, while the NGC catalog is great for pointing the telescope at more obscure nebulae and star clusters.

The database also includes IC and Caldwell catalogs, which covers most of the noteworthy subjects in the night sky. I only wish the database included the Sharpless catalog, for items such as the Tulip Nebula with no alternative designation.

To slew to these objects, it may be better to control the EQ6-R using your PC using supplementary PC-Link cable along with the appropriate ASCOM drivers and software.

I use the hand controller to align, and center my target. After a quick polar alignment routine using the QHY PoleMaster, the pointing accuracy of the mount is spot-on using just a 1-star align.

After you’re aligned and ready to observe or image an object in space, you can start by choosing a target using the “OBJECT” shortcut key, which contains the following object list:

  • Named Stars
  • Solar System
  • NGC Catalog
  • IC Catalog
  • Messier Catalog
  • Caldwell Catalog
  • SAO Catalog
  • Double Stars
  • Variable Stars
  • User Object
  • Deep Sky Tour

The deep sky tour is a very cool feature for visual observation sessions. Imagine a star party or public outreach event where you want to have the best list of targets at the ready.

This feature generates a list of the most famous deep-sky objects that appear in the current night sky overhead. You simply go through the list and pick them off one by one.

The Periodic Error Correction (PEC) Feature

Periodic tracking error is present in all equatorial telescope mounts, and is due to the design of the internal gears. The Sky-Watcher EQ6-R includes a periodic error correction (PEC) function to help correct this.

The PEC training procedure requires that you first polar align and star align the telescope mount. Then, slew to a star close to the celestial equator, and center it in the telescope eyepiece or imaging camera.

Then, navigate to the Utility Function > PEC Training mode and press enter. From here you can select the speed you would like to use for PEC training. The Sky-Watcher SynScan manual suggests using 0.125X sidereal rate for wider FOV telescopes such as the Esprit 100 ED APO.

After selecting the speed using the “1” or “2” keys, the screen will then start to display the elapsed time of the PEC training routine. Now, your job is to keep the star centered in the FOV using the left and right direction keys on the hand controller.

Once the PEC training routine has completed, the elapsed time will stop. Noe, you can select “PEC+Sidereal” as a tracking speed in the Setup menu. It is recommended to wait for at least one PEC training reply cycle to complete before you start taking your images.

Sky-Watcher SynScan Specifications

  • Object Catalog: Messier Catalog, NGC, SAO, Caldwell, Double Star, Variable Star, Named Star, Planets
  • Pointing Accuracy: Up to 5 arc-minutes RMS
  • Tracking Rate: Sidereal Rate, Solar Rate, Lunar Rate
  • PEC: PPEC (permanent PEC)
  • Database: 42,000+ Objects
  • LCD: 18 Characters X 2 Lines (adjustable contrast and backlight)
  • Keypad: Rubber with adjustable backlight
  • GPS: SynScan GPS Modular (Optional)
  • PC Connection: USB or RS-232X
  • Power Output: Power Supply Voltage – 0.7V, Max. 100mA current output

Power Supply for the Sky-Watcher EQ6-R Pro

As one Cloudy Nights forum member put it, the Sky-Watcher EQ6-R Pro can get “cranky” if the right power supply is not used. I have experienced this issue myself, when I used an AC to DC power adapter that did not provide a minimum 4 amps of power.

These days, I use a 12V AC/DC adapter with 10 amps to power the EQ6-R when plugged in at home. Here is a picture of the exact AC/DC adapter I use with the EQ6-R, and here is a link to it on Amazon. Others have found the Pyramid PS9KX 5 Amp power supply to work well with this mount. 

Power supply for EQ6-R Pro

The AC/DC adapter I use to power the EQ6-R Pro mount from home. 

Final Thoughts

As you may have noticed, there is a lot to cover when discussing all of the features of the Sky-Watcher EQ6-R Pro SynScan computerized telescope mount. The very first night I used the EQ6-R, I captured one of my favorite astrophotography images to date, and I knew I was in a for a long relationship with this mount. 

A reliable equatorial mount is the foundation of every great deep sky astrophotography kit, and the EQ6-R is a worthy investment for those looking for a stable, long-term solution for long-exposure imaging.

From my early days with the HEQ5 Pro to my latest session in the backyard with the EQ6, I’ve been extremely satisfied with the user experience and performance of Sky-Watcher’s affordable equatorial telescope mounts. 

astrophotography telescope mount

Pros:

  • Fantastic Tracking when Autoguiding Used
  • Quiet Stepper Motors even Slewing at 9X
  • Easy to Polar Align
  • Built-In PEC Training Feature

Cons:

  • Heavier Than it Looks
  • Intermediate Level Mount with Price to Match
  • Power Supply must be Correct or will Act Up

What Others Have Said:

“This mount is simply amazing. It is robust and tracks very well. I was taking 5-minute subs with no star trails. It is built like a tank and handles my Meade 5″ refractor with ease. The stepper motors are quiet. It’s simply a joy to use and I highly recommend it. The price is well worth it” – James S. on HPS website

“This mount is a tank. I have been doing astrophotography for several years using a lighter weight mount but I was ready to setup up to a heavier payload mount and I am very pleased.” – Ray on HPS website

twitter review

The Sky-Watcher EQ6-R Pro is Available with Free Shipping at High Point Scientific

EQ6-R Pro Review

Useful Resources:

Update the Firmware of your Sky-Watcher EQ6-R Pro SynScan (Sky-Watcher Website)

The Complete User Manual (Sky-Watcher SynScan PDF)

Do you use the Sky-Watcher EQ6-R Pro for astrophotography? If so, let me know your experiences with it in the comments. To stay up to date with my latest adventures in the backyard, be sure to subscribe to my newsletter. Until next time, clear skies!

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Astrophotography in Costa Rica (Carina Nebula)

|Nebulae|16 Comments

I’ve just returned from a vacation to Costa Rica with the goal of capturing some astrophotography images from the resort. Being so close to the equator, the night sky featured many new southern hemisphere deep sky targets I had never seen before.

Aside from astrophotography (including an impromptu Facebook Live stream from our balcony) my wife and I also enjoyed a private birding tour and some much needed relaxation. The average temperature from home in Canada was around -10 degrees Celsius, in Costa Rica, 33.

Despite the pleasant temperatures and impressive number of clear nights during our trip, it took some creativity and persistence to accomplish my astrophotography goals from this location. All-inclusive resorts never sleep, which means that the lights never go out. 

In this post, I’ll share my experiences photographing the night sky from Guanacaste, Costa Rica. For a fun overview of my experience, and some of the raw emotions this trip included, please watch the video.

Astrophotography from Costa Rica (On our honeymoon).

Astrophotography in Costa Rica

The resort we stayed at was Dreams Las Mareas, located in the northwestern peninsula of Guanacaste. The closest city is La Cruz, which is very close to the Nicaraguan border.

While other focused on the all-you-can eat buffet, piña colada’s and catamaran tours, I couldn’t help staring up at an entirely different looking night sky. 

Attempting to take deep sky images through a telescope from a vacation resort in a foreign country has its challenges. As you will soon find out, those uncontrollable variables began to add up.

Costa Rica Map

The location of our resort in Costa Rica.

A Preview of the Southern Sky

The first and most obvious looking change was just how high the Orion constellation was. How fortunate for those that live at this latitude to photograph the Orion Nebula near the zenith!

Below Sirius, in Orion, I saw the bright star Canopus for the first time. This star belongs to the southern constellation, Carina, which is non existent in mid Northern latitude skies.

In fact, there are numerous southern hemisphere constellations and deep sky objects observable from Costa Rica. I thought a trip to Australia would be necessary to see many of these targets.

Southern Deep Sky Objects from Costa Rica

southern deep sky objects

My view of the night sky from 10 degrees north of the of the equator. (Stellarium)

An easy way to get a preview of the night sky from a new location is to download the Stellarium mobile app on your smartphone. Then, you can either enter in the location manually in the settings, or let the app use your GPS for the exact latitude and longitude of your position on Earth.

My android smartphone was set to “airplane” mode during our trip, as I was able to use the resort WiFi for internet access. However, I needed to quickly turn airplane mode off for a GPS signal to get the lat/long coordinates of my location. This may not be necessary depending on your operating system. 

A GPS signal was also needed for my polar alignment process, to display an accurate position of the north celestial pole on the Polar Finder mobile app. If you are interested in the software and tools I use for astrophotography including astronomy mobile apps, be sure to visit the resources page.

mobile apps for astronomy

The Stellarium and Polar Finder mobile astronomy apps were very handy on my trip.

Polar Alignment

Since I was still in the northern hemisphere, I could theoretically polar align my telescope mount using the North Star, Polaris. The north celestial pole doesn’t land precisely on this star, but it’s a fantastic reference point. The process of polar alignment is much more difficult in the southern hemisphere. 

I have polar aligned my telescope mount countless times using the north star from home in Canada, but this time, Polaris sat just above the northern horizon. It was far too low to observe from the resort as it was blocked by the surrounding mountainous landscape and the hotel itself.

To polar align my portable iOptron SkyGuider pro, I guestimated the exact altitude of the polar axis, and it was nearly level with the horizon. At only 10 degrees north, there was no way I’d be able to spot it.

I ran a series of test exposures at 30-seconds in length to improve my rough polar alignment. Luckily the focal length (250mm) of the telescope I brought is more forgiving in terms of tracking accuracy than higher magnification instruments. The RedCat 51 is also extremely lightweight and portable, which makes it a superb choice for wide field deep sky imaging while traveling. 

iOptron SkyGuider Pro

My DSLR astrophotography setup including a telescope and tracking mount.

Portable Astrophotography Gear for an Airplane

I packed all of the astrophotography equipment needed for wide field deep sky imaging in my carry-on bag on to the airplane. This included the telescope, camera, mount, tripod, filter, and adapters.

This “deep sky travel kit” included a capable equatorial telescope mount, the iOptron SkyGuider pro. The EQ head of the mount was easily packed into my bag, along with the wedge and collapsible carbon fiber tripod. This camera mount matches the apparent rotation of the night sky using a right ascension tracking motor.

The telescope is a William Optics RedCat 51 refractor. The RedCat weighs just 3.2 lbs, and can easily be mounted to a lightweight astro tracker for long exposure imaging.

Inside of the RedCat, sits a 2-inch Optolong L-Pro filter that I’ve pre-threaded into the M48 adapter of the telescope. This proved to be a great way to record images in broadband true color while reducing the immediate light pollution from the resort.

The camera is a stock Canon EOS 7D Mark II. When I say “stock”, I mean that this DSLR has not been modified for astrophotography by removing the internal IR cut filter. The camera threads on the RedCat 51 via a dedicated Canon EOS t-ring adapter.

My Portable Deep Sky Astrophotography Rig (Carry-on friendly)

  1. Tripod: Neewer Carbon Fiber Tripod
  2. Mount: iOptron SkyGuider Pro
  3. Telescope: William Optics RedCat 51
  4. Camera: Canon EOS 7D Mark II
  5. Filter: Optolong L-Pro (2″)

astrophotography equipment

The astrophotography gear used for my shot of the Carina Nebula.

The Game Plan

Due to factors such as lack of a precise polar alignment, and setting up in a high traffic area, I decided to shoot 30-second exposures at ISO 6400. This way, I could at least complete a number of successful images rather than having to discard many of them in the pre-processing stage.

The constant wave of wind gusts made keeping my camera and telescope ultra-steady during an exposure very difficult. The limited exposure lengths helped to reduce this effect.

The location of our resort meant that there was very little light pollution in the direction of the nearby Atlantic Ocean. However, this resort chooses to shoot high intensity spotlights toward the night sky during their nightly shows.

There was an unfortunate amount of localized light pollution from the many lighting fixtures that stay on all night long. The mild light pollution filter inside of the telescope adapter helped to reduce this unnatural glow.

I generally like to see all of the lights go out at night, but the lighted pathways on the resort came in handy when navigating to my deep sky imaging location near the front lobby. As an experiment, I took a photo looking towards the constellation Orion from the pathway near our room. As you can see, there is a lot of light coming from all angles.

the night sky

Deep Sky Imaging Location

I decided to stay on the resort to run the camera and telescope. The beach was a better spot in terms of darkness, but it was just too risky to leave the security of the resort at night in a foreign country.

The wind was also much stronger and unpredictable by the water, and I had enough to worry about already. I did, however, sneak down to the beach one night to take some wide angle tripod shots of the night sky. Unfortunately, the timing of this idea was off, as my photos were spoiled due to rare clouds at night. 

Costa Rica Resort

The Location of my Deep Sky Astrophotography Session from Costa Rica.

Shooting from the balcony of our room would have been ideal, but the window of sky was limited to the west. I did attempt to photograph a deep sky object from the balcony through the telescope, but it was more of an experiment than anything else.

There was a large open area of grass outside of the main lobby of the resort, and the security staff by the front entrance gave me some peace of mind. This is where I planted the tripod and iOptron SkyGuider pro with my telescope attached. I kept the tripod very low to the ground for added stability during strong winds.

The Target: Carina Nebula

Coming from a northern hemisphere sky with the usual constellations and deep sky objects, how could I not attempt the Carina Nebula from Costa Rica? This is a “bucket list” target for me, and one I didn’t imagine capturing without a trip to Australia.

The Carina Nebula (also known as the Eta Carinae Nebula) is a magnitude 1 deep sky object, so 30-second exposures were enough to reveal much of this complex and large nebula. This emission nebula is cataloged as NGC 3372, and includes multiple objects within it. 

See this annotated image for a closer look at the many deep sky objects found inside of the Great Nebula in Carina.

The Carina Nebula

  • Distance to Earth: 7,500 light years
  • Radius: 230 light years
  • Magnitude: 1
  • Designations: NGC 3372, ESO 128-EN013, GC 2197, h 3295, Caldwell 92
  • Constellation: Carina

Carina nebula star map

Star map showing the location of the Carina Nebula (Universe Today).

Cataloged deep sky objects inside of the Carina Nebula:

  • Keyhole Nebula
  • Mystic Mountain
  • Trumpler 14 Star Cluster
  • Trumpler 16 Star Cluster
  • WR 22
  • WR 25

The Carina Nebula does not reach a high altitude in the sky from northern Costa Rica, which meant I needed a low view to the horizon to capture it. The Carina Nebula just barely cleared the treeline from our resort at 10pm.

As it turned out, one of the biggest obstacles I had to overcome was wind. The wind gusts were as strong as 40km an hour at times, completely ruining the current exposure being captured on my portable rig.

This element was particularly painful to experience, as it can occur when absolutely every other measure of success has been taken.

To compensate for wind, I used my body to block the telescope from the direction the wind was blowing from. Also, I was limited to 30-second exposures, as this offered the best chance of completing a frame without interruption.

Results

My final image of the Carina Nebula includes just over 9-minutes of total exposure time. The following image consists of 18 x 30-second images at ISO 6400.

Carina Nebula

The Carina Nebula | 18 x 30-Seconds @ ISO 6400

Once I registered and stacked the sub frames in DeepSkyStacker, I had a total overall integration time of 9 minutes, and 30 seconds. Processing the stacked integration in Photoshop was an exciting experience, and I took my time. The individual 30-second light frames were very noisy, which was to be expected when shooting on a hot night using an ISO of 6400.

The stacking process helped improve the signal to noise ratio a great deal. However, the noise reduction actions in post processing seem to have softened the image up significantly. In these situations, it’s a fine balance between noise and overall sharpness.

I really enjoyed processing this image, and loaded it into nova.astronomy.net to be annotated. As you can see, my photo includes NGC 3293, NGC 3324 in the frame as well. This website is a great way to annotate your own astrophotography images online).

our resort

A drone shot of our resort from the beach.

Final thoughts

I would have loved to capture more data on the Carina Nebula, and attempted to capture images of more southern targets like the Centaurus A galaxy. However, I left my new bride in the hotel room during these ventures, and she was very patient and understanding to give me the time I had.

I witnessed the Southern Cross, Carina, Canopus, and much further into the southern night sky than ever before. I could hear the white-faced monkeys in the forest as my camera collected each exposure on the Carina Nebula. I stood alone in a field of grass in the dark while the rest of the guests slept or tied one on at the bar.

Deep sky astrophotography from Costa Rica in early March presents the best of two hemispheres, from Orion to the Carina Nebula. If you are planning on travelling to Costa Rica in the future, I highly suggest that you don’t forget to pack your telescope.

View a high resolution version of my Carina Nebula image on Flickr or Astrobin.

 

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