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Review

ZWO ASI294MC Pro Review (Color Astrophotography Camera)

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The ZWO ASI294 MC Pro is a remarkably capable one-shot-color CMOS camera for deep sky astrophotography. Whether you use it for broadband true-color images on a moonless night or ultra-long-exposure images using your favorite narrowband filter – this camera can produce insanely beautiful images.

This is easily one of the best color cameras I have ever used for astrophotography, and my go-to choice for a night of deep sky imaging. Over the past 6 months, I have used this camera extensively through a number of telescopes in the backyard and beyond.

Here is a taste of what the ASI294MC Pro can do:

M20 - The Trifid Nebula

The Trifid Nebula using a Luminance Filter with the ASI294 MC Pro

This photo of the Trifid Nebula was captured using the ZWO ASI294MC Pro with an Astromania Luminance filter (IR Cut) in front of the sensor. The photo was captured under the dark skies of the Cherry Springs Star Party in 2018.

This incredible camera was loaned to me for review by Stephen Mallia of Ontario Telescope and Accessories. You can purchase the ASI294 MC Pro online from his website.

ASI294MC Pro Astrophotography Camera Review


I can safely say that I now know exactly what the ASI294MC Pro is capable of, and some recommended settings that you can use for a successful image. I’ve used this camera for both full-color images with light pollution filters, an IR cut filter and narrowband filters that separate certain wavelengths of light such as Ha and OIII.

This OSC (One-shot-color) camera performs exceptionally well in both situations. The idea of capturing narrowband images with a color camera is something that is generally advised against in the astrophotography community. This is because a color sensor will essentially record about one-quarter of the detail a mono camera would.

The cheat code, however, is to use a color camera like the ASI294 MC Pro with a duo-narrowband filter like the STC Astro Duo-Narrowband filter. This has the power to build gorgeous deep sky images like the Eagle Nebula example below in a single shot.

The Eagle Nebula

The Eagle Nebula in Ha + OIII (STC Astro Duo-Narrowband Filter)

The photo above was captured in a Bortle Class 8 light polluted area (my backyard) using the ASI294 MC Pro. It showcases both Ha and OIII gases of this Emission Nebula (Messier 16) for some astonishingly detailed results from the city.

This dedicated astronomy camera houses a high-sensitivity type 4/3 CMOS image sensor that supports 4K output at 120 frames per second. It’s a SONY 10.7 MP sensor that produces high-resolution 4144 x 2822 pixel images at its native resolution.

I generally bin my images 2×2, so that just means that my photos are half of that size, in greater resolution. (smaller pixel size). The Bayer pattern of this color sensor is RGGB, which you’ll need to remember when selecting the camera in your image control software, and before stacking.

This camera is well suited for color EAA astronomy (Electronically-Assisted Astronomy), as the ASI294MC Pro includes a 256MB DDR3 memory buffer to help improve data transfer reliability. This is a great feature to consider if you plan on diving into this type of visual astronomy.

You can benefit from the high sensitivity sensor to view more detail in a deep sky object in a “live” looping video feed. Because I am obsessed with collecting images, the only time I experience a glimpse of this feature is when I am framing my target!

Comparing Specs Between ASI Color Cameras:

CameraSensorSensor SizeResolutionPrice
ASI183MC ProSONY IMX1831"20 MPCheck Current Price
ASI294MC ProSONY IMX2944/3"10.7 MPCheck Current Price
ASI071MC ProSONY IMX071APS-C (1.8")16 MPCheck Current Price
ASI128MC ProSONY IMX128Full Frame (35mm)24 MPCheck Current Price

All of the Pro model ASI color cameras include the DDR3 Buffer technology which results in faster data transfer speeds and reduces amp glow. Each one of these cameras requires 55mm of back focus between the image sensor and your flattener/reducer.

Making the Upgrade from a DSLR to a CCD-style camera

When I began using color CMOS cameras like the ASI294 MC Pro, I could no longer use the camera control software I did with my DSLR’s (Backyard EOS). Instead, I use an application called APT (Astro Photography Tool), which allows me to control every aspect of the camera from the cooling temperature to gain.

Upgrading from a DSLR to a CCD type astronomy camera like this is a big transition. For me, the hardest part was getting used to controlling the camera entirely with external software.

The change in image file formats (from .RAW to .FIT was also a bit of a hurdle early on. Luckily, DeepSkyStacker is well suited to stack and de-Bayer this image format into a high resolution .TIF file that you can process in Photoshop.

ZWO ASI294MC Pro Review

The two-stage TEC (Thermo-electric cooling) is perhaps the biggest difference and advantage a dedicated astronomy camera has over a DSLR. As you may know, noise is a big issue to deal with when taking long exposures at a high ISO. I’ve battled with noise for many years (and continue to do so) when processing my astrophotography images taken with my Canon T3i and 5D Mk II DSLR’s.

A cooled CMOS camera like the ASI294 MC Pro can cool its sensor down to 35 degrees below ambient. This results in images that are virtually free of thermal noise. I should mention that it’s important to understand that this means 35 degrees below the current temperature, so if it’s a hot 30-degree night, the camera will max out at -5 degrees.

APO refractor telescope

The ASI294MC Pro Camera attached to my Explore Scientific ED102 Refractor Telescope

Connections and Software

The camera is connected to my computer via a USB 3.0 cable. For the cooling feature, it also requires an external 12V power supply that does not come included with the camera. If you’re anything like me, you have accumulated a number of 12V adapter cables over the years.

To keep things organized and convenient, I now connect the power port on the ASI294MC Pro to the outlets on my Pegasus Astro Pocket Power Box. This means that the camera and telescope don’t have another power cable running to an outlet. It all rides atop the iOptron CEM60 equatorial mount.

The camera is controlled using APT, which required the appropriate drivers from the ZWO ASI website. Installing the driver is painless, and then the “ASI camera” selection will appear from the drop-down menu the next time you connect the camera to APT.

The cooling function is set using the “Cooling Aid” within Astro Photography Tool. It can take a few minutes to get the camera sensor to the temperature you want it. It’s best to get a head start on this process so you’re not waiting around when it’s time to shoot.

A One-Shot-Color Camera – Impressive Specs

I love how sensitive the SONY IMX294CJK sensor is on this camera. The dynamic range of this camera sensor is listed at 13 stops. This is even more than the legendary AS1600 camera from ZWO. This characteristic is thanks to the built-in 14bit ADC (analog-to-digital converter) unit on the 294MC Pro.

ZWO ASI294MC Pro Camera Specs:

  • Sensor: 4/3″ SONY IMX294 CMOS
  • Diagonal: 23.2mm
  • Resolution: 10.7 Mega Pixels (4144 X 2822)
  • Pixel Size: 4.63µm
  • Bayer Pattern: RGGB
  • ADC:14bit
  • DDRIII Buffer: 256MB
  • Back Focus Distance: 6.5mm
  • Cooling: Regulated Two Stage TEC

If you’re wondering what the difference is between the MC-Cool and MC-Pro cameras from ASI are, it’s the DDR3 memory buffer. For non-tech-heads (like myself) this basically means that the camera can transfer data faster and more efficiently. It also reduces amp glow because this artifact is primarily caused by slow transfer speeds.

Here is what the amp glow looks like on a single image captured with the ASI294MC Pro. The amp glow is completely removed after stacking the images with dark frames in DeepSkyStacker.

amp glow

Recommended settings for the ASI294 MC Pro

I find that the best camera settings to use with this camera are to set the gain at “unity gain” and an exposure length of 3 to 5 minutes. This, of course, depends on the deep sky target you are shooting, and the filters being used with the camera.

For example, using a narrowband filter such as a 12nm Ha, I would choose an exposure length of at least 5 minutes. I even shot some images that were as long as 10 minutes with this camera. The photo below shows the Rosette Nebula using a stack of 20 x 10 minutes exposures using the ASI294MC Pro and an Astronomik 12nm Ha filter.

NGC 2244 in Ha

Because the sensor is so sensitive, I can often find my deep sky target in a 2-3 second exposure in live loop mode. This is usually with a strong narrowband filter in front, which is quite impressive. This makes framing the target much easier because you’re able to see the shape and orientation of the DSO (almost) in real time as you adjust the telescope.

Final Thoughts

If you compare the ASI294MC Pro vs. the ASI071MC Pro, you’ll find that the price is significantly more affordable for the 294. I’ve used both of these cameras (The ASI071 camera was the older non-pro “Cool” version), and the image results are remarkably comparable.

The biggest difference between the two cameras is, of course, the sensor itself. The sensor in the AS071 is a 16MP APS-C sized chip, while the ASI294 is a Four-Thirds 10.7 MP sensor. This changes the pixel scale of your images and thus the apparent size of the objects you’ll capture through your telescope.

For APO refractors in the 700-1000mm range, the pixel scale of the ASI294 MC Pro was the absolute perfect size for some of my favorite deep sky targets like the Eagle Nebula and Pelican Nebula.  I used a Starfield 0.8X reducer/flattener with this camera and the various refractor telescopes I used when imaging deep sky objects.

Deep sky astrophotography telescope

If you’re looking to upgrade your DSLR or current color astronomy camera to the realm of “cooled” CMOS sensors – my results with the ASI294 MC Pro should help you make a more informed decision. I highly recommend the ASI294 MC Pro camera if you are in the market for a color astrophotography camera with some serious power and versatility.

The ZWO ASI294MC Pro is available Online from Ontario Telescope and Accessories. I hope you enjoyed this review! If you’d like to stay up to date with all of the future posts on AstroBackyard, please sign up for my newsletter.

Dumbbell Nebula

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Controlling this camera with the ASIair

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Astrophotography Telescope Buying Guide – Under $2000

|Telescopes|2 Comments

Top 10 Telescopes for Astrophotography under $2000

 

Astrophotography Telescope Buying Guide

So you’re in the market for an astrophotography telescope, are you?  There have never been so many affordable options for the amateur astrophotographer on a tight budget.  I am often asked which telescope I use, and which one I would recommend for beginners.  The quick answer is a high-quality, doublet or triplet refractor.  Larger models can be very expensive (and heavy!) due to the high-quality ED glass used.  I think you will be quite surprised at the performance of a small 65-80mm refractor such as the Explore Scientific ED80 I currently use for astrophotography.  To view the types of wide-field images I have taken using this small telescope, please visit my photo gallery.

An astrophotography telescope buying guide?  I thought you were an amateur?  Yes, it’s true, but I decided that since I was doing all this intense research into which telescope I will be buying next, I would share it for others in my position to help streamline your search. I have researched refractors made by Orion, Meade, Sky-Watcher, Tele Vue, Takahashi, Vixen, Astro-Tech, Explore Scientific, Stellarvue and William Optics. Please remember that this is my personal list, and I am by no means an expert! I tried to keep a high standard when browsing for telescopes.

All of the telescopes on this list are apochromatic refractors. I hope this top 10 list is useful for anyone looking to buy a refractor telescope for imaging under $2000 US.  Keep in mind that with my limited budget, I am interested in getting the best balance of aperture, performance, and quality I can afford.  A high-end instrument like the 76mm Takahashi might be the number one choice on your list, but it doesn’t make sense for my situation.  So without further adieu, here is MY top 10 list of refractors for astrophotography:


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10. Tele Vue TV76

Astrophotography Telescope - Tele Vue TV76 Doublet Refractor

 

Thanks to Marc Fitkin, there is an extremely useful and insightful review of this telescope on his blog.  He notes the ability to use this scope as a prime lens for daytime photography as well as astrophotography.  Tele Vue telescopes have a reputation for being top-quality instruments that will last a lifetime. Because I will be using this scope for astrophotography exclusively, a model that excels in visual use has less of an impact on me. The reason this high-quality scope lands at 10 on my list is because it is at the extreme end of my budget, yet has an objective of only 76mm.  Maybe one day I will be in a position to purchase premium-priced optics, but not yet.

Price: $2,000 US (OPT Telescopes)
Accessories Included: Ring Mount, 20mm Eyepiece, 2″ Diagonal, 1.25″ Adapter, Custom Soft Case

 

9.  Sky-Watcher 80mm Esprit ED

Sky-Watcher 80mm Espirit

 

This is another model that comes with an aluminum case, diagonal, and a finder scope – a huge bonus for me.  The heavy-duty Sky-Watcher exclusive “Helinear Track” focuser is a nice touch. This scope actually includes a thread-on field flattener and adaptor for Canon cameras!  A major selling point for someone like me.  I do, however, wonder how much of an upgrade this would be to my current ES ED80. The built-in dovetail is a turn-off for some, but I think it is a great feature.  It is nice to see companies like Sky-Watcher catering to astrophotographers, a trend I am sure that will continue!

Price: $1,649 US (OPT Telescopes)
Accessories Included: Thread-on Field Flattener, 2.7″ to 2″ Adapter, 2″ to 1.25″ adapter, 2″ Diagonal, Canon Camera Adapter, Tube Rings with “V” Dovetail, Carry Case


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8.  Takahashi FC-76DC

Takahashi FC-76DC fluorite doublet

 

I can’t believe there is actually a Takahashi under $2000!  Takahashi has a reputation for building a superior quality astrophotography telescope.  This fluorite doublet is tied with the Tele Vue for smallest objective on this list.  This instrument has the highest quality glass of all the telescopes on this list, and is very lightweight (4 lbs). This telescope operates at a f/7.5 focal ratio, and includes a fixed dew shield. The downsides for someone in this budget are the small objective and 1.25″ focuser (though it can be adapted to 2″ with an additional accessory).  The views through this “Tak” have been described as absolutely stunning.

Price: $1,949 US (OPT Telescopes)
Accessories Included: None

 

7.  Vixen ED103S Refractor

Vixen ED103S Apo Telescope

 

The official product description from Vixen states “ED103S lenses are almost free of chromatic aberration in all colors and are critically sharp edge to edge. The astro-photographer will be especially pleased with the high contrast images through this telescope.”  The dual speed focuser, 4.1″ objective, and overall weight of just 8 lbs is what has me interested in this white beauty.  Not to mention that it’s short tube length of 31.5″ makes it extra portable. A handy in-depth look at this instrument written by Pernel Johnson can be found here.

Price: $1,799 US (OPT Telescopes)
Accessories Included: Tube Rings, Carry Handle

 

6.  Meade 115mm ED APO

Meade 115ED Apo Triplet

 

Meade has catered to the next generation of imagers with this astrophotography telescope.  The older version of this scope was almost identical to the Orion EON 115mm.  The newer Series 6000 model uses an upgraded FK61 extra-low dispersion glass.  Some notable features are the 3″ Crayford focuser, sliding dew shield, and overall build quality.

Price: $1,999 US (OPT Telescopes)
Accessories Included: 3″ Diagonal, Cradle Rings, Mounting Dovetail, 8 x 50 Viewfinder, Hard Case

 



 

5.  Stellarvue SV80ST-25FT

Stellarvue SV80ST-25FT

 

Forum users on astronomyforum.net reported that this Stellarvue Apo has an easy-to-use, well-built focuser. It allows the entire imaging train to screw together, giving you accuracy and stability when imaging. A flattener is a must-have to accompany this scope to eliminate coma, a trait many of these refractors have indeed.  User reviews are very high for this precision instrument with the focuser being the biggest draw.

Price: $1,599 CAN (Canadian Telescopes)
Accessories Included: Tube Rings, Hard Case

 

4. Astro-Tech AT106

Astro Tech AT106 Telescope

 

Sky and Telescope reviewed this scope back in 2009, saying: “the Astro-Tech AT106 provides all the benefits of a first-class 4-inch apo but without the premium price. I highly recommend it.”  I have found a number of positive reviews about this modestly sized refractor.  There is a great in-depth look including sample astrophotos at the scope on Stargazerslounge.com. This astrophotography telescope uses high-quality Ohara glass, and comes with a dual speed 2.7″ Crayford focuser. At just under the $2000 range, (including an aluminum case) This telescope is definitely a top contender for my hard-earned cash.

Price: $1,995 US (OPT Telescopes)
Accessories Included: Hard Case

 

3.  Orion EON 115mm ED

Orion EON ED Triplet Apo

 

An astrophotography telescope from one of the oldest most trusted brands in the hobby.  Time after time, Orion products deliver and continue to impress their reviewers.  My first telescope was an Orion, so this brand holds a special place in my heart. This APO has been around for a LONG time. (I found a review from 2006!) This quality instrument offers excellent color correction by way of the FK-61 extra-low dispersion (“ED”) optical glass in its air-spaced triplet objective lens.  With a focal length of 805mm at F/7, this is a fast, medium wide-field scope.  The extendable dew-shield and multiple knife-edge baffles protect your eyes from off-axis reflections and glare to ensure a view with excellent contrast.  The extra aperture for the price is what puts this scope near the top of my list.  The massive 3″, rotatable , dual-speed focuser is an attractive feature for astrophotographers.

Price: $1,799 US (Orion Telescopes)
Accessories Included: Tube Rings, Dovetail Bar, Foam-lined Carry Case, Starry Night Software

 

2.  William Optics GT102

William Optics GT102

 

There are many fans of William Optics, and for good reason, they make quality instruments for a fair price.  The focal ratio, 102mm diameter objective, and reputation of this scope make this one of my top choices for “next scope”. The optional DDG digital readout on the focuser is a neat feature, and would help me achieve accurate focus with my camera.  I own the WO 72mm Megrez Doublet, and have had many great experiences with it for both astrophotography, and daytime nature photography.

Price: $1,668 US (OPT Telescopes)
Accessories Included: 2″ to 1.25″ Adapter, Mounting Rings, Dovetail

 

1.  Explore Scientific CF 102mm

Astrophotography Telescope - Explore Scientific Carbon Fibre 102mm Apo Refractor

 

With over 4″ of aperture, and weighing just 7 lbs – Explore Scientific calls this the “perfect balance between portability and light gathering power”  The HOYA ED glass is virtually free of chromatic aberration, and produces bright high-contrast images.  The carbon fiber tube is highly temperature stable, eliminating the need for focus changes with temperature fluctuations.  I am not going to lie, I am a little biased towards this telescope because of my unbelievably positive experience with the ED80.

Update: June 2016 – I bought this telescope!

I was contacted by Explore Scientific to upgrade my ED80 to the 102mm CF!  Since then I have photographed many deep-sky objects including this version of the Lagoon Nebula:

 

M8 - The Lagoon Nebula

The Lagoon Nebula

 

Price: $1,729 US (OPT Telescopes)
Accessories Included: 2″ Diagonal, Deluxe Case, Finder Scope Base, Vixen Dovetail

 

Well, there you have it, my top 10 list for anyone in the market for an astrophotography telescope.  As you can see, I plan on sticking with Explore Scientific.  At the end of the day, it comes down to value for me.  If you have any hands-on experience with any of these telescopes and would like to comment, please do so below – I would love to hear them!

 

Astronomy Photo Gallery

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