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Why I’m Switching to a Mono Astrophotography Camera

mono astrophotography camera
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A mono astrophotography camera gives backyard imagers in the city the opportunity to collect dynamic narrowband images from home.  Although LRGB image acquisition using a filter wheel requires some extra setup time early on, the flexibility of this configuration is appealing.

Up to this point, I have not experienced the joys of shooting through a filter wheel. But I have experienced the extraordinary power of a monochrome sensor through narrowband filters. My latest experiences in the backyard have me wondering if I should have switched to a mono astrophotography camera a long time ago…

I’ve Seen the Light, and it’s in Monochrome

Those of you who shoot with a one-shot-color astrophotography camera (such as DSLR) as I did for many years may be hesitant to switch to a camera that spits out black and white images. The satisfaction of a colorful nebula appearing on the back of your camera display screen after a 120-second exposure is why we got into this hobby in the first place.

Make no mistake, a color DSLR camera remains the best option for beginners looking to get started in the deep sky. I’ve spent the past 7 years doing so, and nothing will ever match the enjoyment of capturing objects in space from a dark sky site with a camera and telescope.

photography through a telescope

Yet experienced backyard astrophotographers insist that monochrome is the only way to go if you want to get serious about your deep-sky imaging. I took a lot of flak last year when I decided to upgrade from a DSLR to a One-shot-color Altair Hypercam 183C, particularly when shooting through narrowband filters.

The results of my color camera + narrowband experiments were promising, but I knew those 12nm filters were better suited for a mono sensor.

In this post, I’ll tell you why I’ll be shooting with a mono astrophotography camera from this point forward. But first, have a look at the Altair Hypercam 183M in action on the Cone Nebula.

Why do serious amateurs recommend a mono camera over color?

A monochrome astrophotography camera can collect more signal (light) than a color camera can. (3 times as much, to be exact). The Bayer filter array found in a color camera reduces the amount of overall light recorded on your astrophotography subject.

By design, a camera sensor with a color filter array requires you to take longer exposures to record the same level of signal as a mono camera would. By automatically collecting light through your telescope into separate RGB channels as the light is collected, you are sacrificing the full potential of the light you work so hard to collect.

Bayer filter

The Bayer filter found on color CMOS camera sensors. Wikipedia

In this article from, Dillon O’Donnell weighs the pros and cons of using a mono camera for astrophotography over color. In the end, it comes down to a trade-off between convenience and quality.

A color camera will get you to the finish line faster but will hold you back in terms of image quality at a certain point. You may photograph objects through your telescope for years before you reach a point where you feel like your progress has plateaued.

The bottom line is, a color camera is a jack of all trades, master of none.

mono vs. color camera

Left: The Cone Nebula using a monochrome camera and narrowband filters. Right: The Trifid Nebula using a modified Canon DSLR with an LPS filter.

Making the switch the switch to mono

Let’s get one thing straight, my color astrophotography cameras (DSLR’s) will not collect dust on the shelf as I begin to focus on capturing images in monochrome. Creating beautiful full-color images of space will always be my primary goal.

For most projects, I simply don’t have the time (clear skies) to collect all of my data using a monochrome camera with the necessary filters. In a nutshell, I’ll capture color images around the new moon, and narrowband mono images the rest of the time.

I’ll never stop shooting in color with a DSLR, but new monochrome data will give my existing color images a real boost.

Color astrophotography camera

Won’t it take three times longer to produce an image?

The added time involved with a mono astrophotography camera has been labeled a “myth” by some of the CCD manufacturers.  Until I invest in a filter wheel and run through the entire process for myself, I can only speculate that this simply can’t be true.

It’s possible that the overall image acquisition process time could be shortened due to the fact that more light is collected in each sub. Manually swapping out filters for each channel would tip the scales the other direction, but an automated setup including a filter wheel would speed this up.

camera though telescope

I thought a cooled CCD was the only way to go?

Everybody knows that a cooled CCD camera is the best choice for serious deep-sky astrophotography, what’s all this about CMOS sensors (that DSLRs use)?

Advances in CMOS technology have the latest astrophotography cameras that use CMOS sensors performing nearly as well as the coveted CCD. If you’ve been calling a non-DSLR dedicated astronomy camera a CCD, you’re not alone. Many software applications such as Astro Photography Tool label these CMOS astronomy cameras as a “CCD” to distinguish them from a DSLR camera.

CCD cameras vary in price by a wide margin, from the tiny Orion StarShoot G3 Deep Space Camera to “the ultimate in astronomical imaging”, the SBIG STX-16803.

For a wealth of information about CCD cameras, have a look at this video from Atik Cameras.  Stephen Chambers, of course, references cameras from the Atik line, but much of the information he shares applies to all astronomy cameras.

A monochrome CMOS image sensor

After several years of photographing deep-sky targets in color through a Bayer filter,  I am now realizing the difference a camera with an improved quantum efficiency makes.

As you may have guessed, my heart once belonged to one-shot-color DSLR astrophotography. But, I am quickly realizing how a monochrome astronomy camera can give backyard imagers a tremendous advantage. It’s hard to imagine shooting with a color camera with a narrowband filter now that I have seen how much more detail can be acquired in mono.

Benefits of a monochrome camera:

  • minimize the effects of light pollution (nb)
  • excels at capturing emission nebulae
  • photograph fainter objects
  • image during the full moon (nb)
  • ability to capture a wider range of objects

Have a look at this infographic shared by Atik Cameras.

monochrome cameras

The Altair Hypercam 183M

astrophotography cameraToday, I have in my hands a new Altair Hypercam 183M astronomy camera. This camera uses a monochrome Sony IMX183 sensor that can also be found inside cameras from ZWO and QHY.

The Altair Hypercam 183M camera lacks thermo-electric cooling, which is a big reason it is more affordable than its cooled mono competitors.

Even without a TEC system, the Hypercom sensor remains remarkably cool during a long exposure imaging session thanks to the open body design and fan cooling.

I put the Hypercam internal fan design to the test last summer on the 183C, and I was impressed at the difference it made. On the hottest summer nights, the DSLR remained on the shelf while the Hypercam pressed on.

Altair Hypercam 183M Specs:

  • 20MP Sony IMX183 BSI CMOS Sensor
  • Fan Cooling with temp. sensor
  • 1″ CMOS Sensor (5440 x 3648 active pixels)
  • Built-in amp glow reduction
  • high dynamic range (12 bit ADC to 16-bit output)

The Altair Hypercam 183 requires the appropriate drivers to operate.  You can download them from

Telescope in the backyard

Plans for deep sky imaging in monochrome

I once believed that moving to a darker location was the only way I would be able to photograph faint and challenging targets. When you couple narrowband filters with a highly sensitive mono CMOS sensor, you’ve got what it takes to break through even the worst city light pollution.

For now, I’ll focus on capturing luminance data or isolated narrowband gas details with the 183M. I can apply this new data to existing deep sky color photos for some added punch. Moving forward, adding a filter wheel to the mix will allow me to create completely new versions of my favorite objects.

Adding mono details to a color image

I’ve added new mono details using the 183M to my image of the Whirlpool Galaxy from 2014 in RGB

I’ll be sure to create a new Photoshop tutorial in the future that includes the process of adding a luminance layer to existing color images. The added “light” can make a dramatic impact on your images and provide some much-needed contrast and clarity to your photos. It is especially effective on nebulae with plenty of hydrogen gas.

Early deep sky image results

The Cone Nebula is a tough shot to get from a red/white zone. My previous attempt using a color camera and a telescope (and hindsight) that wasn’t a good fit for an object this size, did not go so well. The chip size of the 183M is a good match to the focal length of my ED102 refractor telescope. (714mm @ F/6)

This time, however, my Explore Scientific ED102 was called into action, with the Altair Hypercam 183M attached. Also, I decided to sacrifice instant color gratification for more details. The image was shot the day after the full moon, and it was shining uncomfortably close to my target during this session.

The Cone Nebula in Mono

The Cone Nebula and Fox Fur Nebula using the Altair Hypercam 183M

Image details:

24 x 5 minutes (2 Hours Total)
Gain: 40%
Black Level: 100

Telescope: Explore Scientific ED102
Camera: Altair Hypercam 183M V2
Filter: STC Optical Duo-Narrowband Filter
Guide Scope: William Optics Z72 Doublet
Guide Camera: Altair GPCAM2 AR0130 Mono
Mount: iOptron CEM60

Stacked in DeepSkyStacker

Image Processing in Adobe Photoshop.

For the image above, I used an STC Optical duo-narrowband filter that isolates both Ha and OIII and blocks out almost all other wavelengths of light. It’s designed to ignore city light pollution while enhancing the wavelengths of Ha and OIII. Although this 48mm filter worked brilliantly with the Mono camera on the Cone Nebula, I need to test this filter with my DSLR.

STC Optical duo-narrowband filter

The Transmission Rate spectrum graph of the STC Optical Astro Duo-Narrowband filter

Plans for the Future

The Cone Nebula was my last imaging session with the winter targets, as objects on their way out to the West are not available in my backyard window.

Galaxy season is approaching, and with it, come numerous new targets for deep sky astrophotography. This time around, I’ll shoot with a longer focal length to pull the often tiny subjects into view. The telescope I’ll be using is an iOptron Photron RC6. This will be a brief departure from my refractors as we head into spring. The timing couldn’t be better.

Until next time, clear skies.

Update: In early 2019 I added a cooled CMOS monochrome astronomy camera to my set up, the Meade DSI IV


How to Choose a CCD Camera

This is a great resource from Diffraction Limited that provides a better understanding the importance of focal length, light sensitivity and resolution in an astronomy camera. This is the company responsible for the iconic SBIG line up of CCD Cameras.

ZWO ASI Website

ZWO offers a wide range of high sensitivity CMOS astronomy cameras.  To date, I have enjoyed the ASI071MC-Cool (Color) and the ASI294MC-Pro (Color). The ASI 1600MM-C is currently one of the most impressive monochrome astrophotography cameras being used by backyard astrophotographers around the world.

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This Post Has 32 Comments

  1. Jim Blackwell says:

    i was astounded at your mono image of the cone nebula. The depth and detail were incredible, especially given the conditions that night (bright moon). Good work!

  2. Trevor says:

    Thanks very much Jim! I am itching to try this camera out on some summer nebulae when they return:)

  3. Thanks for posting this Trevor. I am planning on doing the same thing, even before getting a new scope. Right now I am leaning towards the ZWO1600 although the ZWO183 or ZWO 178 might be OK. I entered the sensor sizes into Stellarium and compared them to the Canon T3i and discovered that the ZWO1600 is close to the T3i. The others are much smaller and would give a cropped image (smaller FOV). Unfortunately this have to wait as my wife was laid off in December.

  4. Phill says:

    I’ve enjoyed all the videos you’ve done Trevor, you make it all seem easy.
    But in the picture of the video above with the caption

    “I finaly started using a mono astrophotography camera”

    The look on your dogs face seems to say ,oh boy here we go again .
    I love it .
    Regards Phill

  5. Mark Blundell says:

    I moved to imaging with a mono ZWO ASI1600MM-cooled camera with electronic filter wheel just over year ago and I haven’t looked back. Just one word of warning, the data you are going to get with these cameras is so much cleaner that it’s very tempting to over process the image which I’ve done on several occasions as I did last year with M51 which I have now reprocessed (which I believe you’ve seen on Twitter).
    One last thing keep the video clips coming I enjoy watching them.

  6. Helber says:

    I wondering if it’s true that the total time (acquisition + processing) can be as short with a colour camera. I’m waiting for your experience with an automated setup to know it.

    I started my experiences with mono and I can say that if clouds come before finish one of the channels: no colour image that night.

    What about use Sequence Generator Pro for automation?

    Thanks you for your videos.

  7. Mark Blundell (UK) says:

    My imaging time is only a little bit more doing LRGB then when I used a DSLR. With my DSLR I used to do 36 to 48 (3-4h) 5 min subs. With my “ZWO ASI1600 mm cooled” I do 1-2min for my luminance and 2-3min for my RGB. I can’t go much longer then this (unless I’m doing oiii/Ha bi-colour) as the quality of my skies Won’t let me. As for processing, I would say easier as you have cleaner/better data to work with but not necessarily quicker, I would say now I’m more formilier processing mono it’s about the same but then ever image is different. Last night (20th March) I imaged ngc4725, I did 60 Lum [email protected] and [email protected] for each R,G,B let’s see how that turns out, FYI the sky were not great but I was getting desperate for some imaging time☹️. As for clouds rolling in, I tend to do my luminance in one go at the beginning but split rgb in to batches, for example:- My imaging plan would take 8 Red 8 green and 8 blue subs and then repeat this 2 more times giving me a total of 24 of each, this way if the clouds roll in you hopefully have something of each channel to work with.

  8. Al Milano says:

    Great Article! Those are some wonderful cameras.
    I’d like to switch (from DSLR) also. The disproportionate expense is a bit of a hurdle.
    I wish some companies would consider making more affordable models…

  9. Joseph Stafford says:

    Hello Trevor,
    I was wondering how much cooler the sensor gets with the cooling on the Altair 183M or 183C than a regular dslr. Im assuming its about 10’C cooler but there does not appear to be anything regarding this subject on the internet.Thanks.

  10. Congratulations fot your blog Trevor.

    I have a doubte, with your explorer scientific ED 102, with the reducer and this CCD you have a resolution about 0,82 arcsec/pix, really with the HEq5-Pro it’s possible to manage this requeriment?

    I live in Spain, it’s a hot weather country…, this not cooled CCD camera can be a good choice?.



  11. Peter says:

    Hello Trevor and others!

    Please, I’m a newbie and I don’t understand how such a small mono sensor could be possibly better than APS- or full-frame-sized DSLR?

    Thank you!

  12. Phil says:

    I’ve been using the 183Cv2 in Australia and it isn’t cutting it on hot nights. I’m now waiting for the TEC version of the mono to be released.

    • Trevor says:

      Hi Phil. I hear you. We’ve had a week straight of 30+ nights here in Ontario and I’ve opted for my cooled color camera in place of the 183M for the same reason. I’ll be demoing a new cooled mono camera next month!

  13. Doug Griffith says:

    Hi Trevor.

    I have been vicariously enjoying your astro journey since I became interested 15 months ago.
    The STC duo band filter seems like a good fit for a project I envision; and might save swapping H-a and OIII filters in the cold.
    Did you purchase it directly from STC…or is there a North American (or better still…Canadian) distributor?

    Thanks in advance.


  14. Trevor says:

    Hi Doug! The STC Astro Duo-Narrowband filter is available from the William Optics website: (It looks to be out of stock at the moment) – I got mine directly from William

  15. Jo says:

    With a monocam you get higher true color resolution, since the color information is collected separately for EACH pixel, whereas with the colorcam only 25% of the pixels collect red, 25% blue and 50% green. Color reconstruction is done computationally. What is missing in a 1shotcolorcam is the luminescence channel. You added that using your monocam to an older RGB (3 channel) image here.

    What is not optimal is using your monocam with a DUAL wavelength filter, since you are losing the color information from the two different wavelength. The DUAL wavelength filters are most useful with a colorcam, which will automatically process the image to reflect the colors of the two wavelengths. With a monocam you are getting more information using a single wavelength filter, since you can then reconstruct a color image later. You cannot do that with a dual wavelength filter, since that information has been lost during capture.

  16. Trevor says:

    Thank you very much for the information, Jo. I’ll stick to the color camera when using a duo-narrowband filter. I look forward to creating new color images using a monochrome camera and a filter wheel in the near future. Thanks again for the advice!

  17. Benjamin Law says:

    Hello, I have ordered the STC Duo-narrowband filter for my ASI294MC-Pro. May I ask how do I stack the frames (each has both Ha and Oiii data) from Deep Sky Stacker? Do I just stack them the way I do it normally?

    What about processing in pixinsight? Do you have any web reference for me to check the processing workflow in PI for the duo-narrowband images? Thank you.

  18. Raul says:

    Thank you, nice post. Actually I have an ASI294, do you think that could be interesting adquiring an ASI1600 mono to take images at once with two telescopes and combining them? (1600 for luminances and 294 for color). Thanks.

  19. Asuka says:

    I don’t know much about this, but does it make sense, if you now use red, green and blue Filters to get 3 Photos with separated color channels in 16-Bit, which might give a 48-Bit color Photo after processed in Photoshop or similar?
    Please don’t laugh, if this idea is too funny.

  20. Chuck says:

    If I want to use a monochrome camera just for that purpose i.e., to process all my images in b&w…… is it necessary to also still use the different LRGB filters… I still need them for better b&w images or will just imaging in monochrome be sufficient? As recently as 2013 I was still using my home darkroom developing and printing in b&w. There have been many DSO images that are more appealing to me in b&w than color….just curious, thanks.

  21. Rayman says:

    Doesn’t seem you’ve completely made the switch to BW as you use the one shot color cams in your newer videos. Seems that color won you over?

  22. Trevor says:

    LOL – You’re right on the money there, Rayman. Soon after demoing my first (uncooled) mono CMOS camera – I got the ZWO ASI294MC Pro. Shooting in OSC now is a lot of fun, but I realize HOW much data I am missing out on per sub using a color camera, especially with NB filters! I’ve actually got something in the works with a mono camera again (finally), but this time it’s a CCD!

  23. Peter Wolsley says:

    I am about to jump from my Ha modded Nikon D5300 to a cooled CMOS camera. Either the ASI294C or the ASI1600M. Can you tell us what MONO CCD camera you are referring to?

  24. Doug Pontius says:

    Thanks for the info, Trevor! Great stuff! I just switched to a ZWO 1600MM this Christmas, and I’ve been shooting with an HA filter and getting good results. But the dual narrowband filters (like the STC) that I already bought for my ZWO color cam are all advertising OSC-only, and I’m thinking WHY? Does a filter really care if there is a Bayer matrix sitting behind it? Why not capture multiple wavelengths in mono? I only have five slots in my SX filter wheel, but I might try swapping in my STC or OptoLong for the HA and see what I get. Definitely loving the extra sensitivity that the mono camera gives. I’m still working on the mono pre-processing workflow though 🙂

  25. Al Force says:

    Best advice for light polluted environment? ZWO ASI294MC or Altair Hypercam 183C ???

  26. Mosthated says:

    Are we looking at the same picture here I mean the picture on the right blows the one on the left out of the water at least 3x lol

  27. Bergen says:

    Awesome info Trevor. It looks like im about 3 years behind you in this journey. I have a dual imaginging setup with one osc cooled and one not cooled. Both zwo183. Thinking of upgrading the non cooled to a mono. But undecided on if i should go cooled.

    Happy new year to you and yours😁

  28. KK says:

    thank you for this article. I understand this reply is pretty late, but I wanted to highlight a major issue that the article missed or glosses over. “Focus” , when shooting mono and set of filters, you have to refocus for every filter you have in the image train. This is a huge turnoff unless one invests in an auto focuser and a filter wheel all integrated together. Each wavelength of light focusses at a different point. This is just optics in action.

  29. LF says:

    Hi Trevor.
    Always enjoying your posts. I live in the country side in Denmark with completely dark skies. Not even a street lamp. But in Denmark we don’t have a lot of clear nights. I have up until now used a modded DSLR but I am looking to take a step further and buy a new camera. I read your review of the ASI294MC which you gave a glowing review. I am currently considering that camera, but after reading this article I am unsure if shooting LRGB or HaRGB on the ASI1600MM would be a more futureproof solution. It takes longer with a mono which is not ideal with the few brigt nights we have, but then it seems more usable during nights with moon thus creating more nights to shoot. How big is the difference quality wise would you say. Is the mono worth the extra time spent?

  30. Trevor,

    As always, I appreciate when you share what you are learning. I do wish you had added a third photo to your comparison of the mono and RGB + Luminance versions of the Whirlpool Galaxy. Can you please add the RGB version to the other two so we can see side-by-side comparisons of the before and after adding Luminance.

    Here is my 1 hour 40 minute version of this same subject:
    To save space, you have posted your pictures at very low resolution, but even at the resolution I used on my website, if you zoom in you will notice that the picture gets very grainy pretty quickly. I have learned a lot since six months ago and I’m hoping I can retake this picture when spring galaxy season returns and get a much better image. I keep thinking about switching to monochrome, but I shudder at the cost of replacing my cameras.

  31. LF: When I look at photos on websites where people use mono cameras I notice that they will take between one and two hours for each of the four photos (LRGB). Even at the long end, this is eight hours of exposure time. Recently, after reading articles in Astronomy and Sky & Telescope, I have been shooting between six and nine hours for my one shot color photos. I often cannot get that much time in a single night. Many of my photos are at four to six hours and are waiting for another chance to up the total time. The articles I referred to say really deep space photos require nine hours. The work I see with LRGB mono cameras are getting the same or better pictures in eight hours. Seems to me like the time savings is on the side of mono cameras. If you want an explanation of why the shorter times on mono gives less grainy final pictures than one shot color, I can attempt that but it would take a post twice the size of this one.

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