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Lagoon Nebula

How I Photographed a Nebula with a $200 Camera Lens

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Taking impressive deep-sky astrophotography images is not reserved for those using an astronomical telescope. A budget camera lens can be used to take images of some of the best deep-sky objects in the night sky.

A telephoto zoom lens can provide enough magnification to pull distant objects in space in for a closer look, but you’ll need to find the lens’ “sweet spot” for a clean shot. In this article, I’ll share exactly how I photographed a colorful nebula region in space using a budget camera lens and a DSLR camera.

In my latest video on YouTube, I photographed a nebula in the night sky using a $200 camera lens. The photo turned out really well, and I think it’s an eye-opener to anyone that thinks a telescope is needed for a task like this.

Lagoon Nebula

The Lagoon and Trifid Nebula region photographed with a $200 Lens.

Although I do most of my astrophotography in the city, it should come as no surprise that I usually get much better pictures from a dark sky location (it really depends on the project). Light pollution washes out the night sky and can make it more difficult to locate and photograph your target. 

For the photo shown above, I traveled to a dark sky park located about 45-minutes from home. The location is special to me, as it was where I took my first image of the Lagoon Nebula through a telescope in 2013.

Nebula Photography with a $200 Camera Lens

In the video, you’ll see me set up my camera and lens to photograph the bright Lagoon Nebula that lies toward the center of the Milky Way core. 

The Lagoon Nebula is a stunning emission nebula in the constellation Sagittarius. The Lagoon Nebula is big (90 × 40 arcmins), bright (apparent magnitude +6.0), and it sits right next door to the beautiful Trifid Nebula.

If you’re new to astrophotography, you may want to stick to the brighter nebulae targets until you really get your system ironed out. Brighter nebulae like this make focusing, framing, and even image processing easier.

You can use an astronomy app on your smartphone to filter out the brightest objects available in the night sky. The dimmer and smaller the object, the tougher the entire process becomes.

astrophotography camera lens

Using a Telescope vs. Camera Lens 

My first deep-sky photo of the Lagoon Nebula was taken using a DSLR camera and a thousand-dollar astronomical telescope (Explore Scientific ED80). The telescope delivered crisp, well color-corrected images of my subject at a focal length of 480mm.

Telescopes, such as the apochromatic refractor, are designed to focus pinpoints of light (stars) without color fringing (chromatic aberration). They often use much longer focal lengths than a camera lens (higher magnification) and include robust focusers that allow you to fine-tune your focus position. 

Explore Scientific ED80

The Explore Scientific ED80 Apochromatic Refractor.

When it comes to deep-sky imaging, an astrophotography telescope will usually beat a camera lens every time, both in terms of the imaging experience and the results. 

After all, telescopes are designed to observe and photograph deep-sky objects at high magnification, camera lenses are not. 

Camera lenses excel at wide-angle shots such as Milky Way photography and nightscapes, but when long focal lengths are needed, you can’t beat an astronomical telescope.

However, the average person doesn’t own a telescope, but they may already have a DSLR camera and zoom lens at their disposal. At a focal length of 150mm and above, the larger deep-sky objects begin to reveal themselves in a long exposure image.

To prove that amazing deep-sky photos are within the grasp of an ordinary camera and lens combo, I chose to use one of the most entry-level kits I could get my hands on.

A Beginner DSLR Camera and Lens Combo

A dedicated astronomy camera is built for long-exposure deep-sky imaging, but if you own a regular daytime camera, you can still take fantastic astrophotography images.

For this project, I used one of the most affordable DSLR cameras on the market, the Canon EOS Rebel T7. I purchased this camera and lens as a bundle from B&H Photo Video earlier this year.

DSLR camera

The Canon EOS Rebel T7 kit lens bundle.

The bundle included two lenses, the Canon EF-s 18-55mm F/3.5-5.6 IS, and the Canon EF 75-300mm F/4-5.6.

The Canon Rebel series of DSLR cameras are entry-level camera bodies, suitable for beginner to intermediate photographers looking for complete control over their shot. 

I’ve owned many Canon Rebel DSLR’s over the years, from the XSi (450D) to the T3i. I highly recommend these reliable cameras for beginners looking to take their astrophotography to the next level. 

The entire kit cost less than $600 (including the camera body and two lenses), but you can buy the Canon EF 75-300m F/4-5.6 lens on its own brand new for $200. 

The Lens

The Canon EF 75-300mm F/4-5.6 III is a budget camera lens that allows you to shoot at focal lengths of anywhere between 75-300mm. 

I’ve covered the astrophotography performance of this lens before, and it continues to impress me. As expected, this lens performs much better at lower f-stops.

I wouldn’t recommend shooting wide-open at F/4 for astrophotography. I’ve found F/6.3 to be a great middle-ground between light-gathering power and star quality.

  • Lens Mount: Canon EF
  • Focal Length: 75mm-300mm
  • Type: Zoom Telephoto
  • Focus Method: Extending Front
  • Autofocus: Yes
  • Image Stabilization: No
  • Weight: 480 grams (1.06 lbs)
  • Elements: 13
  • Groups: 9
  • Filter Size: 58 mm
  • Lens Coating: Super Spectra Coating
  • Type: Zoom
  • Maximum Aperture: f/4-5.6
  • Specialty Type: Telephoto

If you watched the video I made earlier this year (kit lens challenge), you’ll know that this affordable camera lens exceeded my expectations by a long shot.

Canon EF 75-300mm lens

The Canon EF 75-300mm F/4-5.6 lens used for my photo.

Shoot Longer with a Star Tracker

I don’t think the average person realizes that it’s possible to photograph nebulae in space that are thousands of light-years away with an ordinary camera and lens.

However, there is one key piece of astrophotography equipment that is critical for a truly amazing shot.

The key to capturing a great photo with a camera lens like this is the star tracker. The star tracker compensates for the rotation of the Earth, and a moving sky.

It’s essentially a smaller version of a motorized equatorial telescope mount, like the heavy-duty ones I use with my larger telescopes.

star tracker for camera lens

My camera and lens on a star tracker.

I highly recommend the Sky-Watcher Star Adventurer to anyone looking to purchase their first portable star tracker for astrophotography. 

The star tracker allows you to take long-exposure images at long focal lengths (a maximum of 300mm with this lens) without star trailing. For the star tracker to work effectively, you must polar align the axis of the mount to the celestial pole. 

If you don’t have a star tracker, you can still take images of nebulae like this, but you will be limited to much shorter exposures because the stars will begin to trail after only a few seconds.

astrophotography

Aligning the polar axis of the star tracker with the North Celestial Pole.

When you compensate for the rotation of the Earth, all of a sudden exposure time isn’t a concern anymore.

You are free to experiment with less aggressive ISO settings, lower f-stops, and an exposure length that’s suitable for your tracker’s capabilities.

Star trackers, like the Star Adventurer, require you to manually locate and frame your subject and this can be difficult if your object is small and dim.

focusing the camera

Focusing the camera on a bright star using 10X Live-View.

If there aren’t any bright stars in the same field of view as your target, you may need to focus first and then pan over to your intended imaging location. This is quite common when getting set up. 

A red dot finder may help you align your camera lens with your subject, and a planetarium app such as Stellarium will help you “star-hop” your way to the general area. 

Expect to take several test exposures (15-30-seconds each) before you actually start taking your long-exposure images on your target. 

Camera Settings and Advice

At a focal length of 100-200mm, exposure lengths of about 2-3 minutes will provide enough data per shot to produce a great image. 

You’ll collect plenty of signal (light) in each shot, without having to crank the ISO up (which can increase noise) and you’re not asking too much out of your little star tracker.

I recommend using “maxed-out” settings (high ISO, fastest aperture) for the framing and focusing process, and to take a lot of test exposures until you are happy with the framing and sharpness of the object.

camera settings

I chose to use a focal length of 200mm on this zoom lens. This allowed me to capture the Lagoon Nebula at higher magnification, yet still capture a wide field of view of the area.

I used a roll of electrical tape to secure the lens at the 200mm position. This is an important step to remember, as you could easily lose your original focal length position while focusing the camera lens. 

Focusing the camera lens on a deep-sky object can be challenging. In my case, I had to turn the LCD display up and switch to ISO 6400 for the brightest stars in the frame to stand out.

Related Post: How to Focus Your Camera for Astrophotography

Once I was satisfied with the centering of my object and the focus, I switched back to my imaging settings, which is a less aggressive ISO 1600 at F/6.3.

The stars looked a little too bloated for my liking at F/5, and bumping the aperture down even 2 stops can make a big difference in terms of overall image sharpness.

Lagoon Nebula with a camera lens

Camera Settings for my Photo

  • Mode: Manual
  • File Type: RAW
  • Exposure: 120-seconds
  • Number of Exposures: 45
  • ISO: 1600
  • F-Stop: F/6.3
  • White Balance: Auto
  • Focus: Manual
  • Focal Length: 200mm (TAPED)

Equipment Setup Breakdown

The star tracker must be mounted securely to a sturdy tripod to operate correctly. I use a carbon fiber tripod that is lightweight, sturdy, and ultra-portable. 

A remote shutter release cable is necessary if you want to tap into longer exposure times (beyond 30-seconds) on your DSLR camera and automate a sequence of long-exposure images to fire off on their own.

Because the star tracker is battery-powered, the entire setup from top to bottom is completely portable and does not require any additional power to operate. Bringing an extra set of batteries for the star tracker and the camera will help avoid cutting the imaging sessions short. 

A dew heater is recommended to avoid moisture on the camera lens, but this will require an additional power source to run (a portable USB charger device may be all you need). 

A small Bahtinov mask may make focusing easier, but it is not essential for a tight focus. Using the 10X live-view zoom on your DSLR camera will help you find critical focus on a bright star.

Here’s the complete setup I used to photograph the Lagoon Nebula with a camera lens.

portable deep-sky astrophotography setup

My portable deep-sky astrophotography setup.

My Results

The final picture includes 45 x 2-minute exposures at ISO 1600. The images were shot in RAW image format and stacked together using dark frames in DeepSkyStacker (DSS).

DSS is a free stacking software and a personal favorite of mine. Sequator is another excellent choice, and many people prefer the simplicity of this software over DSS. 

As you collect more exposure time overall, the signal-to-noise ratio is improved, and you are left with an image that can be processed effectively. 

The single image frames have a brown, washed-out appearance (see below), but this is easily corrected during the post-processing stages. 

sub exposures

My individual image exposures (sub-exposures) on the Lagoon Nebula.

The final image was carefully stretched (curves) in Adobe Photoshop to bring up the brightest areas of the nebula. The colors were carefully balanced (setting the black and white points), and a healthy amount of saturation boost was applied.

Other techniques used were star reduction, gradient removal, and selective color boosting. All of these topics have been covered in detail on this website over the years. 

To learn more about the image processing techniques I use, please see my premium astrophotography image processing guide

Lagoon Nebula

The Lagoon and Trifid Nebulae by Trevor Jones.

If you are just getting started in astrophotography, I hope that this post has inspired you to take a second look at the camera equipment you may already own and start using it for the night sky.

For my latest astrophotography adventures, feel free to subscribe to AstroBackyard on YouTube and Instagram. Clear skies!

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Canon Rebel Astrophotography

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The very first camera I used for astrophotography was an old Canon Rebel Xsi (450D) DSLR. Even though the production of this camera was discontinued many years ago, I still use and enjoy this camera today.

A DSLR camera like the Canon Rebel 450D is a versatile choice as it can easily be attached to a telescope for deep sky imaging using a T-Ring and adapter. You can also use this camera with fantastic camera lenses such as the Rokinon 14mm F/2.8 for wide-angle nightscapes and Milky Way photography.

I’ve used many types of cameras for astrophotography from monochrome CMOS imaging cameras to cooled one-shot-color models. My Canon Rebel DSLR’s continue to produce amazing images, and they are one of the best ways to get started in the hobby.

The Milky Way

The Milky Way captured with a Canon Rebel T3i on a SkyTracker Pro Mount

Astrophotography with a Canon Rebel DSLR

I eventually upgraded my DSLR camera to a (slightly) newer Canon EOS Rebel T3i (600D), and it came pre-modified for astrophotography. The modification that was made to this camera is known as the “full spectrum modification”, which involved removing the stock IR cut filter inside the camera body.

Although there are many choices to consider when it comes to choosing a camera for astrophotography, an entry-level Canon Rebel series DSLR offers a unique combination of value and performance.

In this post, I’ll share my personal results using the Canon Xsi DSLR for astrophotography, and give you my recommendations for a beginner DSLR camera.

Canon Rebel Xsi for astrophotography

The Canon Rebel XSi a popular DSLR camera for amateur astrophotographers

If you don’t own a telescope yet, but want to get into astrophotography using a DSLR, have a look at the following resource page: Astrophotography Tips You Can Try Tonight

Capturing Deep-Sky Targets with a DSLR

The moon’s glaring presence has subsided, and it is now time to gather more RGB (color) light frames on my coveted summer deep-sky milky way objects. This is now my 5th summer as an amateur astrophotographer, and I don’t like to waste time when choosing my target for the night.

During the months of May-July, the Messier objects located near the core of the Milky Way have my full attention. My favorite summer deep-sky objects lie within the Sagittarius region of the Milky Way Core. Many of them are bright and colorful such as the Lagoon Nebula, Eagle Nebula, and the Swan Nebula.

The Lagoon Nebula is one of my all-time favorite targets and a worthy photo opportunity for any DSLR camera and telescope. The summer emission nebulae in Sagittarius are so bright, it is possible to photograph them from a light=polluted area such as your backyard in the city. My backyard skies are rated a Class 8 on the Bortle Scale.

From my latitude in the Northern Hemisphere (Ontario, Canada), the main aspect to consider is having a clear window of sky to the South, as most of the summer Milky Way targets travel Southeast to Southwest throughout the night.

Canon rebel astrophotography

 

The Lagoon Nebula using a Canon EOS Rebel Xsi

The photo of the Lagoon Nebula above was imaged over several nights last week. I set up my telescope gear on June 30th, July 2nd, and July 3rd over the Canada-Day long weekend in my backyard. It’s rare that we have such a long stretch of clear nights, especially on a long weekend.

This colorful nebula does not rise very high in the sky from my latitude in Southern Ontario. In fact, it just barely clears the height of my backyard fence. When planning a deep sky imaging session, it’s important to have a clear view of your target for an extended period of time.

I consider myself very lucky to be able to photograph such a glorious night-sky treasure from home.  You can view the specific photography details for my final image on my Flickr profile. I also managed to squeeze in some more imaging time on the Eagle Nebula, as well as the Elephant’s Trunk Nebula over the weekend, as you will see further down the post.

Capturing Galaxies

I have photographed many galaxies with my Canon EOS Rebel Xsi from the backyard. One of my most successful images was the Triangulum Galaxy. A long stretch of clear nights allowed me to collect over 7 hours of exposure time on M33.

This is a diffuse deep-sky object which can make it difficult to observe visually, but through photography, we can reveal the beautiful structure and color of this galaxy. The telescope used to capture the image below was an Explore Scientific ED80 with a focal length of 480mm.

Triangulum Galaxy

The Triangulum Galaxy using a modified Canon EOS Rebel Xsi

For Beginners / Newbies

You can view the equipment I use to take images like the ones on this website here or watch this video as I take you through my complete setup for astrophotography.

If you already own a DSLR and telescope and have started taking your own astrophotos – you may benefit from my astrophotography tutorials about image processing.

I connect my Canon Rebel DSLR to my laptop computer using a USB cable and control the camera through a software application known as BackyardEOS.  With this application, I can tell my DSLR to take multiple exposures of varying lengths and ISO settings.

Backyard Telescope

My Canon Rebel Xsi attached to an astrophotography telescope

I can also use this program to focus the stars, and make sure that my astrophotography subject is in the center of the frame. A typical session in my backyard will last all night long and have my Canon Xsi set to take anywhere from 30-60 three to four-minute exposures on a nebula or galaxy.

Dark frames of the same temperature are also captured during the night to reduce noise in the final image. As a general rule of thumb, the colder your digital camera is while imaging, the better!  Long-exposures taken during a hot summer night will produce even more noise than usual.

The Canon Rebel series DSLR cameras are also well-suited for Moon photography. If you connect the DSLR camera to a telescope, you benefit from its long focal length (compared to most lenses) for an up-close look at our nearest celestial neighbor.  

Moon through a telescope

If you are interested in this aspect of solar system astrophotography, be sure to have a look at my Moon photography tutorial. The Moon is an excellent target for your DSLR camera at any focal length. 

Hot Summer Nights

On a recent attempt to gather some H-alpha data on the Elephant’s Trunk Nebula, I discovered the limits of my DSLR when imaging in the hot summer heat.  On this particular night in Mid-June, the temperature remained over 30° well after midnight.

This was just too hot for my Canon 7D to capture any useful data on my deep-sky target.  (I use a different DSLR for my H-Alpha captures, as my Canon Rebel Xsi has the LP filter fitted to it at all times)

The hot hazy skies, combined with a dangerously hot sensor produced a red, noisy mess of an image.  An exposure of 30 seconds to a minute may be fine in this heat, but I was shooting 7-minute subs at ISO 1600 to pick up faint nebulosity through a narrowband 12nm Ha filter.  Lesson learned!

I have since returned to the Elephant’s trunk nebula in the constellation Cepheus, and let me tell you – it is faint!  Photographing IC 1396 from a light-polluted backyard in the city has proved to be quite the challenge.  I was able to capture about 2 hours of exposure on this nebula last week, which is not enough to produce a pleasing image.

By stretching the data far enough (using curves in Adobe Photoshop) to show the rim of the nebula, the background stars become blown out and noisy.  It takes many hours worth of imaging to produce a decent portrait of this DSO.  Here is my early result with limited exposure time:

IC 1396 - Elephant's Trunk Nebula

The Elephant’s Trunk Nebula in Cepheus

Best Beginner DSLR for Astrophotography

I have stood behind the Canon brand of DSLR’s from the beginning. Based on the advice I read in the Backyard Astronomers Guide back in 2010, I chose to start my photography adventure using Canon digital cameras.

At the time, they were the clear choice for astrophotographers, offering the only DSLR built for astrophotography (They later released the Canon 60Da)  Nikon has come a long way since then in the way of astrophotography, but my heart still belongs to Canon.

The Nikon D810A is a camera intended for astrophotography, as you may have gathered with the “a” designation in the title. This is Nikon’s first DSLR dedicated to long-exposure astrophotography. This camera body was based on the original D810, but include a sensor that is four times more sensitive to H-Alpha red tones than an ordinary DSLR.

Canon EOS Rebel T3i

In 2015 I upgraded to Canon EOS Rebel T3i camera for astrophotography. The T3i (600D) came pre-modified by an astro-modification service known as “Astro-Mod Canada”. I have used this camera to capture many deep-sky objects using various clip-in filters.

This is the DSLR I always recommend to beginners. First of all, it is the successor to the Canon Xsi which I use now and can provide actual results (my photo gallery) of the astrophotography performance of this camera. Second, it is a great value.

Canon Rebel T3i

You will find used models of this camera body at online retailers (such as Henry’s in Canada) for a fraction of the price of a new CCD Astronomy Camera.  You can no longer purchase this camera new, so if you can’t find a used body at camera retailers, you will have to search online forums such as Canada Wide Astronomy Buy and Sell, or Astromart.

This camera can also quite easily be modified for astrophotography by yourself or a professional.  The features of the camera itself are quite standard of all models these days, but this DSLR is capable of taking astonishing deep-sky and landscape astrophotography images.

My favorite feature of the T3i is the flip-out LCD screen. This comes in very handy when shooting deep-sky astrophotography images because the camera is often in an awkward position when connected to a telescope.

Tilting the screen to a more accessible angle allows me to focus the telescope using the 10X live-view function of the camera. I can also review the histogram, make changes to the exposure time, and review my light frames as they are being captured.

The Canon T4i and T5i are also excellent choices but are a little more expensive.  The Canon T5i can be purchased in a kit including an 18-55mm lens.

Recommended Clip-in Filters

I have used a wide variety of clip-in light pollution filters with my Canon Rebel DSLR cameras. For deep-sky targets containing hydrogen-alpha emission data such as the Eagle Nebula, a narrowband filter like the 12nm Astronomik Ha is an excellent choice.

For capturing broadband RGB data on my targets, the SkyTech CLS-CCD filter allows me to block a healthy amount of city glow. This filter creates an impressive amount of contrast between your object and a light-polluted sky.

For broad-spectrum targets such as galaxies or reflection nebulae, I recommend trying the Optolong L-Pro filter. This multi-bandpass filter is less aggressive and helps retain the natural colors of the stars in your image.

DSLR camera filter

The Optolong L-Pro filter in My Canon Rebel 600D

Why use a DSLR?

There are many different types of astrophotography cameras available, other than Digital SLR’s. Dedicated thermal-cooled CCD cameras are much better at producing deep-sky images with less noise, but are much more expensive and less user-friendly.

Webcams can produce stunning images of Solar System planets and the moon and can be inexpensive and easier to use. The Altair Hypercam 183C is an example of a dedicated astronomy camera that can bridge the gap between a DSLR and a CCD.

I still enjoy using a DSLR because it’s an enjoyable experience. You can’t beat the value and versatility of the Canon Rebel series cameras.

Light Pollution Map

I often speak of the light pollution from my backyard in the city.  I love to get away from home to image under dark skies at my astronomy club’s observatory (RASC Niagara Center) – but I rarely have time to drive 40 minutes with all of my equipment to this special place.

To maximize my time under the stars, it makes more sense for me to get as much astrophotography in at home, in the backyard. (Hence the name of this website) The light pollution produced by the city I live in is quite heavy, especially in certain areas.  My house is in the worst of it, being located in the central area of town.

I found this helpful Light Pollution Map that shows just how bad it really is:

Light Pollution Map

Light Pollution Map for my Backyard

The Bortle Scale

Do you see that?  I am in a Red Zone!  I would estimate that my location is either a class 7 or 8 on the Bortle Scale, although I have not yet taken an accurate light pollution measurement.  The Bortle Scale states that a class 6 zone (NELM 5.1-5.5) will have your surroundings easily visible and that the Milky Way is visible only at the Zenith.  

These characteristics are true of my backyard and is referred to as a bright suburban sky. How much light pollution is in your backyard?  You can use this nifty interactive map to find out: Light Pollution Map

To view all of my best images captured with a Canon Rebel Xsi and T3i, check out my photo gallery.  I wish you all the best in your future astrophotography endeavors, clear skies.

Helpful Resource: Getting Started with Deep Sky Astrophotography

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Astrophotography from a Light Polluted Backyard

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Backyard Astrophotography

Summer would not be complete without spending a night enjoying the dazzling beauty that is the constellation Sagittarius. The “teapot” asterism just clears my fence to the south of my backyard in central St. Catharines. From my latitude, August is my last chance to image the many star clusters and nebulae that populate this area.

Last night, I set out to gather as much light on the Lagoon Nebula and the Trifid Nebula as possible before they dipped below the trees. With the nights being so short at this time of year, it is important to have your astrophotography equipment setup process down-pat.

As soon as Polaris is faintly visible in the North, I begin my calibration and alignment process on my trusty Sky-Watcher HEQ5 mount.

The summer triangle in the night sky

In the photo above, you can see the Summer Triangle asterism as seen from my backyard. This photo was processed extensively to reduce the light pollution present from my city backyard. When shooting through the glow of a bright city, it if often best to shoot your deep sky targets when they are directly overhead to avoid the light dome. 

The Light Pollution Effect

I should mention, that the third-quarter moon rose at midnight last night. (I ended my imaging session at 11:30pm) Enhanced detail and better contrast would be easier to pull out of this image if my imaging session took place closer to the new moon.

Light pollution is also a major factor where I live. My backyard lies within the border of a red/white zone for light pollution (Bortle Class 8). Surprisingly enough, however, I can still just barely pick out the Milky Way with my naked eye.

To compensate for this unfortunate reality, I use an IDAS Light Pollution Filter to help block out the unwanted light from the street lights and porch lights that surround me.

Wide Field Deep-Sky Image

The Trifid and Lagoon Nebula in the constellation Sagittarius

With my brief window of opportunity, I was able to take (14) 210 second exposures at ISO 800 with my modified Canon Rebel Xsi. Once stacked, the total exposure length equaled a whopping 49 minutes!

Despite the challenges mentioned above, I think I was able to produce an acceptable image of this summertime deep-sky treat. My 80mm telescope offers the perfect opportunity to capture both nebulae in the same field of view.  This will likely be the last photo taken in this rich and starry area of the Milky Way until next year, when it rises again in the Spring.

M8 and M20 Wide Field Image

M8 and M20 in Sagittarius

Telescope: Explore Scientific ED80 with WO Flat III 0.8x FR/FF
Mount: Sky-Watcher HEQ5 Pro Synscan
Guiding: Meade DSI Pro II and PHD Guiding
Guide Scope: Orion Mini 50mm
Camera: Canon EOS 450D (Modified)
ISO: 800
Total Exposure: 49 minutes (14 x 210 seconds)
Image Processing Software: DeepSkyStacker, Adobe Photoshop CC
Support Files: 9 dark frames

Backyard astrophotography setup

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Creating an Astrophotography Mosaic

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I have been spending a lot of time photographing the night sky towards the core of the Milky Way. My 80mm refractor has a focal length of 480mm, which magnifies many deep-sky objects in the area of Sagittarius

The Lagoon Nebula and the Trifid Nebula lie very close together in the night sky, as far as emission nebulae go. With the right camera sensor, and a wide-field imaging refractor (such as the Radian Raptor 61), you should be able to fit both objects within the same field-of-view. 

When the photo below was taken, my framing was a little off. I could have fit both objects in a single image frame with my Canon EOS 60Da DSLR camera with the right orientation.

lagoon and trifid nebula

I had quite a difficult time aligning these images up, as I did it manually in Photoshop. The hardest part was the fact that both objects were processed separately, under very different shooting conditions.

I now know the importance of framing the objects in my field, especially when planning a mosaic. Creating a mosaic is a great way to photograph a large area of the night sky in detail.

They allow you to create beautiful, high-resolution images that look great when you zoom in. You can use your existing telescope (and camera) to photograph large nebulae and galaxies that are just too big to fit in a single frame. 

mosaic

Large deep-sky objects such as the Heart and Soul Nebulae are often captured using the mosaic method.

Creating an Astrophotography Mosaic

At first, you might not understand why astrophotographers would spend so much time building an image piece-by-piece. After all, if you want to capture a large area of the night sky, you can simply use a shorter focal length,

The problem with that method is, the image will lack resolution and detail. The deep-sky objects may not appear sharp and well-defined up-close. If you plan to print a large format image, you may be underwhelmed with the overall quality of the image.

There are free mosaic tools to help you create your image including Image Composite Editor. This is a photo-stitching tool that allows you to “drag and drop” your images onto a single canvas, and it will automatically analyze and stitch them together. 

Reasons To Create a Mosaic

  • Capture a large field of view using a long focal length
  • Create large images showcasing entire nebulae regions and areas of interest
  • Create a high-resolution image suitable for large-format printing
  • Create detailed portraits of the Moon’s surface
  • Create a hybrid image by blending photos shot a different image scales

As you increase the overall size of your astrophotography mosaic by adding panels, you add resolution too. Many amateur astrophotographers state the overall megapixels of the image, which is the height (in pixels) multiplied by the width (in pixels) of the entire image.

For example, an image that is 6000 pixels wide by 4000 pixels tall is 24 megapixels (24MP).

Related: Get My Premium Astrophotography Image Processing Guide

How To Create an Astrophotography Mosaic

The act of creating a mosaic image in astrophotography involves capture multiple areas of the night sky and merging them into a single image. This is done when the field of view is too tight to capture an entire object (or interesting area of the sky), or when you want to capture a high level of detail over the entire image.

There are several fantastic examples of Mosaics on AstroBin. I must admit, I have not completed many astrophotography mosaics in my day. I usually opt to shoot large areas using a full-frame camera sensor (such as the Canon EOS Ra) and a wide-field optical instrument. 

However, this will never achieve the level of detail and resolution a large mosaic image will. Amateur astrophotographers will often create mosaics of the moon, to reveal ultra-high-definition details of the lunar surface.

Acquiring the Image Panels

To create a successful mosaic image, you must carefully plan your imaging session to collect each panel of your intended image frame. Plate-solving will help with this, and there are several tools in software such as Sequence Generator Pro (SGP), and TheSky to help you with this.

Sequence Generator Pro includes a handy Framing and Mosaic Wizard that allows you to fetch the target area, define the camera scale and pixels, and more. The level of automation possible with this routine is remarkable. 

The following video explains how to use the framing and mosaic tool in SGP in detail. 

If you’re not using the framing and mosaic tool in Sequence Generator Pro to plan your mosaic projects, you can still apply the same techniques on your own. 

When collecting your data, the key is to include an adequate amount of overlap area so that you can safely merge the panels together without creating visible “seams”. Most astrophotographers recommend at least a 10% overlap area to safely merge the images together without the worry of having to photograph a new panel. 

mosaic panels

Planning the panels of a large astrophotography mosaic.

Photographing the panels at the same focal length and aperture are important to match the image scale of the image. This part is easy, as long as you are using the same telescope or camera lens for the entire project. 

One of the more challenging aspects of creating an astrophotography mosaic is the ever-changing imaging conditions. Light pollution can be a factor, but also the moon phase. Frames shot during a full moon (even narrowband data) will look washed out compared to new moon data. 

It is possible to create a nightscape or deep-sky mosaic using images shot at varying focal lengths, but you will need to perform some careful scaling and alignment in Adobe Photoshop. I prefer to manually align and scale my mosaic images in Photoshop, using a soft feathered edge between panels. 

Building a Mosaic Image in Photoshop

Photoshop’s layer system was designed for tasks like this. Adjusting the opacity of each layer before applying it to the final image is a must. A transparent image will help you line up the stars at the edges of each panel with each other.

Bring all of your image panels into a single laid photoshop file as layers. You may want to use a reference image of the final framing to use as a base layer at the bottom

You can adjust the opacity of each layer (see below) to 50% to align the stars of each panel up with each other. When all of the layers are properly aligned, you can set each layer back to 100% opacity.

create a mosaic in Photoshop

The graphic above shows why capturing a healthy amount of overlap area is important. If there is a gap between image panels, you will need to go back out and photograph the missing areas.

Take advantage of the guidelines tool (View > New Guide Layout) in Photoshop to help align each panel together. In the example above, a full-color, processed image is shown. In reality, this stage should take place before any major processing tasks have taken place.

You may want to perform a simple stretch in PixInsight or Photoshop applied evenly to each panel before aligning the images. A mismatch in processing techniques between panels will result in an odd-looking image.

Enhance Detail and Resolution to Existing Images

If you have captured a wide-field image of an area of the night sky, you can photograph individual objects at higher magnification and apply them to the larger image. 

I would consider this to be a hybrid mosaic image because you are starting with the wide-field image first, and applying high-resolution details to it gradually. The technique isn’t perfect, of course, as you will still have large areas of the image in a lower resolution than the rest.

In the example below, you can see how I applied high magnification images of the Lagoon Nebula and Trifid Nebula to an existing wide-field image. 

astrophotography mosaic

High-resolution images are applied on top of a wide field image to improve details. (outlines for reference only).

The same technique can be applied to images of the moon. In the example below, I merged a high-resolution image of the moon (captured through a telescope), with a wide-field image of the moon with passing clouds all around it. 

This photo is a better example of HDR (high-dynamic-range) at work than creating a mosaic, but the sample concept of scaling images to increase overall resolution is at play. 

The Moon

A better example of the power of mosaics in moon photography is this incredibly detailed image of the moon by Andrew McCarthy. Massive lunar close-ups are fun to explore up-close and would look wonderful printed and framed on your wall. 

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This article was originally published in 2013, and updated on January 7, 2021.

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M8 – The Lagoon Nebula

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The following image is of the Lagoon Nebula in the constellation Sagittarius. Ever since I got into Astrophotography, I’ve wanted to image this nebula because it is so big and colorful. Emission nebulae are some of the most beautiful and colorful objects in the night sky.

I photographed this deep-sky target using my 80mm refractor telescope, the Explore Scientific ED80 Triplet APO. My DSLR camera (stock Canon Rebel Xsi) was attached to the telescope using a t-ring adapter and mount. I also used a 2″ William Optics 0.8X Field Flattener/Reducer that was designed for use with F/6 telescopes.

M8 - The Lagoon Nebula - Astrophotography with Telescope and Canon Rebel XSiM8 – The Lagoon Nebula

I have been having some focus issues as of late, but luckily this night the stars were sharp through each sub. If you are having trouble focusing your camera for astrophotography, I have put together some tips for beginners.

This is a stack of 4-minute exposures totaling just under 2 hours. To integrate the exposures into a single image, I use a free software called DeepSkyStacker (see my DeepSkyStacker tutorial). I was able to capture a wider field of view thanks to my new William Optics Field Flattener.

Progress on the Lagoon Nebula

Since the photograph of Messier 8 at the top of this page was taken, I have photographed this area of the night sky many times. Here are a handful of tries on this target so you can see my personal progress.

astrophotography

The biggest lesson I have learned when processing astrophotography images in Adobe Photoshop is to take a look at the image on a per-channel basis. This makes it much easier to control individual elements of the image such as:

  • minimizing stars
  • boosting color and saturation
  • sharpening details
  • reducing noise
  • balancing colors

If you want to learn everything I have learned about processing astrophotos over the past 10 years, please consider downloading my premium astrophotography image processing guide. You can also get a better understanding of the equipment I use for deep sky astrophotography by visiting this section of the website. 

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