Having the 2600MM Pro, should I keep the 294MC pro? - Forums

Hi all,

I have the ASI2600MM Pro with 7 filters (SII, OIII, Ha, L, R, G, B). I use it with my Skywatcher Esprit 80ED and my Explore Scientific ED127 CF.

Now after some issues with a vendor (won’t bother you with that), I just received a brand-new ASI294MC Pro. Question is: why should I keep it? I already have a great camera (the 2600M) that can work with true color images. using the LRGB filters. It also has better specs (perhaps except for the resolution).

So is there any reason to not sell the 294?

Thanks for your advice!

Ard

PS I realise that all of us would like to have these kind of problems :-)

You can never have too many cameras ! I say keep it !

Keep and set it up another scope. Running two rigs in a night will double your targets per night.

As with most things in this hobby, it really comes down to personal preference. On one hand, your 2600MM even with bad filters absolutely smokes the 294MC in every category. On the other hand, it’s hard to disagree with ScottF. If you’ve got the gear to run a second rig, that’s a great option as well. But again, there’s personal preference involved. If they were both mono or both OSC, I would absolutely do it. But having one camera so much more dominant than the other, I would personally feel like everything I shot with the 294 would have to be re-done later on the 2600 anyway. So, there’s less benefit for me.
Another factor to possibly consider is whether or not you ever travel with your gear. If you ever find yourself traveling somewhere with dark skies but have limited time, OSC is fantastic for that. Otherwise, unless I’m overly concerned with pixel size/sampling, there’s not a single scenario where I would choose the 294 over your 2600.

I am the opposite case. I own the 294MM and the 2600 MC Pro.

I have taken very good images with both. I have never felt that one sensor "dominates" or "smokes" the other, nor a burning desire to redo all my 294MM images with a future 2600 sensor. The 294MM (and MC) is certainly more demanding of flats and darks than the 2600, but entirely manageable; that said, I do like that I don't need to care about flat times being more then 3 seconds with the 2600MC. Resolution differences between the two are not meaningful unless you are blessed with great seeing. The base sensor QEs are identical.

If your MC calibrates well, I'd be inclined to keep it. Have it connected to the more portable of your two scopes and take it when you travel to a dark sky site. It will give you great images. If your money is burning a hole in your pocket, sell the 294MM and buy a 2600mC and you can have the best of all worlds 😀

To clarify, I will admit the spec sheets even on ZWO’s own website give conflicting information for the 294. That being said, the QEs I pulled showed 75% for the 294 and 91% for the 2600. Full well was also something like 17k versus 50k and read noise was more than double on the 294. They were extremely massive differences. Of course, this also makes me question the spec sheets from the dealers as they typically just copy it off the ZWO website. Even the pixel size is different on ZWO’s site depending on which link you click on.

When I got my 2600M (I have the ToupTek one, but for the sake of the discussion, same thing) I sold my 1600MM Pro + EFW + Filters and my Player One IMX294 OSC camera thinking ‘This IMX571 mono is superior to both these cameras, I no longer need them….’

I wish I still had my IMX294C.. Im looking at picking up a IMX585, IMX533 or IMX294 colour camera soon as a secondary… Honestly, when I want to shoot a narrowband image, I would never want a colour camera… and I want to be able to shoot RGB stars, so I need my RGB filters too… But honestly, If I’m shooting a broadband target like a galaxy, or a big reflection nebula, I would happily shoot OSC and be done with it… Less to think about, less to do in post processing.. On some targets, like dark nebula, I’d probably reach for my mono camera for the big boost I get from Luminosity… but otherwise, OSC for broadband imaging is ideal in my opinion.

Unless - Unless you can afford an IMX571 mono, and and IMX571 osc, then you can shoot your lum for a couple of nights with the mono, then spend a night pulling in OSC data to add colour…

At the moment, I shoot everything in LRGB / SHO (or a mixture of the two) because I don’t have any other option. Given the choice though, keep that colour camera…

ScottF · Nov 5, 2025, 05:05 PM
Keep and set it up another scope. Running two rigs in a night will double your targets per night.

or build a second rig with a 0.75x the focal length, and then you’ll have matching fields of view… Shoot Lum and Ha on the mono cam, at the same time pull down OSC data to add RGB stars/colour.

Jaymz Bondurant:
To clarify, I will admit the spec sheets even on ZWO’s own website give conflicting information for the 294. That being said, the QEs I pulled showed 75% for the 294 and 91% for the 2600. Full well was also something like 17k versus 50k and read noise was more than double on the 294. They were extremely massive differences. Of course, this also makes me question the spec sheets from the dealers as they typically just copy it off the ZWO website. Even the pixel size is different on ZWO’s site depending on which link you click on.

You have to compare the QEs of the mono to mono sensor. Or color to color. Addition of a color Bayer array drops the QE due to the absorption by the pigments in the Bayer array and it will be roughly the same in both cases. The mono to mono sensor comparison shows both at around 90%.

Comparing full well capacity should be done very carefully too. The FWC of the 294MM is nominally lower because the pixels are smaller (2.3 vs. 3.76 micron). A smaller pixel will, of course, naturally have smaller FWC. Normalized to the same area, both have identical or near identical FWC. Similarly, the noise numbers need to be compared with care as well - the pixel sizes are different.

Arun H · Nov 6, 2025, 03:52 AM

You have to compare the QEs of the mono to mono sensor. Or color to color. Addition of a color Bayer array drops the QE

Why would you compare it to a camera you don’t have? We’re literally comparing a color camera to a mono camera. The Bayer matrix dropping the QE is exactly why the mono camera has better QE.

Jaymz Bondurant:
Arun H · Nov 6, 2025, 03:52 AM

You have to compare the QEs of the mono to mono sensor. Or color to color. Addition of a color Bayer array drops the QE

Why would you compare it to a camera you don’t have? We’re literally comparing a color camera to a mono camera. The Bayer matrix dropping the QE is exactly why the mono camera has better QE.

If you want to play that game - the integrated area under a Bayer array is greater than the integrated area under a comparable mono sensor with RGB filters. OSCs are actually a bit more efficient at capturing pure RGB color data than mono. It is a myth that mono is better at color data. OSCs can capture more complex hues than mono - for example, an OSC can capture correctly white light split into its spectral components (like a rainbow); a mono, which lacks band overlap will not. See John Upton's detailed calculations on the topic It is the addition of "L" that improves the mono performance.

Thank you all

I live in a bortle 3/4 area.

I am not too worried about the ampglow stuff and calibration images on the 294. Also I have have the filterwheel so collecting RGB with the 2600 is just a matter of programming the ASI AIR. And I don’t have a problem with the extra processing steps that a mono introduces. And not overly concerned with oversampling/undersampling.

I think they are both good camera’s and if I would not own the 2600 already, I am sure that I would be VERY happy with the 294.

I wonder that if I sell it, I would get more than 60-70% of the price in a shop. If so, then it makes sense to consider selling it. If not then it makes sense to keep it and play with it, perhaps even setting up a second rig.

I am not in a hurry so I can give selling it for the right price a try.

But ….. I think I already know where this is going: I will get not much for this camera, despite it being completely new. And it will end up in my collection after all. And I will learn for which type of targets I will prefer one camera over the oher 😉

Again: thank you all for your reactions.

I would sell the 294MC Pro and buy a 533MC Pro instead. Taking flats with the 294MC isn’t an enjoyable experience, and some of these sensors have uneven light sensitivity, which can cause strange gradients in your images. I had this issue with mine and tried everything I could during the two years I owned it, but after switching to the 533MC Pro, I haven’t had a single problem.

I also have a 2600MC, which has been completely trouble free.

Arun H · Nov 6, 2025, 04:17 AM
If you want to play that game

I’m not sure what game you’re referring to. I gave my opinion and was very careful to say more than once that it all depends on personal preference. Upton’s calculations are correct. But they also only apply to acquisition. Those gains get canceled out during the Bayer interpolation step. There are nuances to everything. And it’s all personal preference. If your main concern is color, go with whichever one you think gives you the best color. If your main concern is SNR, stick with the mono. If your main concern is sampling, stick with the one that gives you the best sampling for your setup and skies. I love a good learning opportunity and to discuss people’s personal preferences. But to argue for the sake of arguing or to “play that game” doesn’t really help anything. And it seems the OP has made a decision. So, it’s a moot point. Clear skies to all!

Arun H · Nov 6, 2025 at 03:52 AM
Jaymz Bondurant:
To clarify, I will admit the spec sheets even on ZWO’s own website give conflicting information for the 294. That being said, the QEs I pulled showed 75% for the 294 and 91% for the 2600. Full well was also something like 17k versus 50k and read noise was more than double on the 294. They were extremely massive differences. Of course, this also makes me question the spec sheets from the dealers as they typically just copy it off the ZWO website. Even the pixel size is different on ZWO’s site depending on which link you click on.

You have to compare the QEs of the mono to mono sensor. Or color to color. Addition of a color Bayer array drops the QE due to the absorption by the pigments in the Bayer array and it will be roughly the same in both cases. The mono to mono sensor comparison shows both at around 90%.

Comparing full well capacity should be done very carefully too. The FWC of the 294MM is nominally lower because the pixels are smaller (2.3 vs. 3.76 micron). A smaller pixel will, of course, naturally have smaller FWC. Normalized to the same area, both have identical or near identical FWC. Similarly, the noise numbers need to be compared with care as well - the pixel sizes are different.

That’s if you shoot the 294mm in bin1, the colour version doesn’t have that option and bin 2 gives a pixel size around 4.6 and full well of 63700.

That’s if you shoot the 294mm in bin1, the colour version doesn’t have that option and bin 2 gives a pixel size around 4.6 and full well of 63700.

Yes, this is the point I was trying to get across. Comparing full well capacity is not meaningful without taking into account the difference in pixel size. As you note, normalized to a common pixel dimension - the FWC of the two sensors are very close. We need to remember that photon incidence per square sensor area will be determined by the optics. For similar optics, both cameras would display similar pixel saturation behavior.

The other poster made a statement to the effect that Bayer interpolation loses the gains from increased photon capture due to the larger bandwidth of the Bayer filters; I have no idea what he is basing this statement on - but the easiest way to show that this makes little sense is to see that Bayer interpolation is not needed at all. Modern stacking software uses CFA drizzle at 1:1 which, given that the color matrix undersamples, will recover the lost resolution and give images in all three channels that do not have Bayer interpolation artifacts, and have SNR properties that are in line with the photons captured, which will, for RGB, be actually greater with a color camera.

In the end, the OP received good, balanced advice. The biggest advantage he has is that he is in a B3-4 zone. Both his cameras will give him very good results.

Ardje · Nov 5, 2025, 04:22 PM
Hi all,
I have the ASI2600MM Pro with 7 filters (SII, OIII, Ha, L, R, G, B). I use it with my Skywatcher Esprit 80ED and my Explore Scientific ED127 CF.
Now after some issues with a vendor (won’t bother you with that), I just received a brand-new ASI294MC Pro. Question is: why should I keep it? I already have a great camera (the 2600M) that can work with true color images. using the LRGB filters. It also has better specs (perhaps except for the resolution).
So is there any reason to not sell the 294?
Thanks for your advice!
KR

Ard
PS I realise that all of us would like to have these kind of problems :-)

I'm in the exact same situation: I have the 2600MM with a filter wheel and I also have the 294MC Pro. And... I'm keeping it!

The reason is simple for me: I use them for completely different purposes.

The 2600MM (Mono) is the camera I use from home, from my "fixed" setup. It's the obvious choice for long projects where I can dedicate multiple nights to collecting data (one night for L, one for Ha, one for RGB, etc.) for maximum quality.
The 294MC (OSC), on the other hand, is my "travel" camera or for "single nights."

The key point for me is efficiency. If I go to a dark site and have only one night available, I don't want to risk it.

With the Mono, if I shoot a nebula (L-R-G-B) and clouds roll in after 3 hours, maybe I finished L and R, but I'm missing G and B. I go home with an incomplete image.

With the OSC, I set it up and hit start. Every single frame contains all the RGB data. If clouds roll in after 3 hours, I still have 3 hours of complete color data and a finished image.

So yeah, I'm keeping it precisely for its efficiency in those "grab-and-go" sessions.

(And honestly... I'll keep it until I decide to swap it for a 2600MC!)

Yeah, tough problem to have. 😀

I would keep it for two reasons. One, you have a spare camera. Two, you can set up one widefield rig and one medium focal length rig and be able to image all of that real estate in RGB and narrowband: buy a uv-ir filter and complementary Dual-band filters (Ha-Oiii and Sii-Oiii) and use it with the 80mm. Keep the full mono rig on the 127mm. Best of widefield and longer focal length at a reasonable price. Works best if you have a second mount, but depending on your current mount’s capability, you could piggyback.

The 294 does have its issues as noted but it is quite a capable camera. Also as noted, you aren’t going to recoup the full cost of it selling it and then what? Spend more when you really don’t need to?

That’s an interesting thought: piggy backing. I have n iOptron CEM70 mount which can carry almost 32kg. I thought that for astro imaging it is recommended to stay at roughly half the maximum capacity so that would mean 16 kg. Quick calculation tells me that combining the 127 and 80 and cameras and guide scope and EAF, would add up to ca 18 kg so I guess that should be fine.

I wonder if the images of the 80 and the 127 would be combinable in stacking? Or otherwise ‘manually’ in postprocessing but I guess that this will not be a huge problem.

Interesting. The 294 is for sale now, but if I ‘need to keep it’, I’ll definitely have a closer look at this option.

Thanks for the advice.

I wonder if the images of the 80 and the 127 would be combinable in stacking? Or otherwise ‘manually’ in postprocessing but I guess that this will not be a huge problem.

Yes this is possible and many people do it. You can use the 294MC for RGB and 2600MM for luminance as an example and PI will have no problem combining them. You can piggyback or do side by side as long as your mount has the capacity. You would need to use synchronized dithering, which is available in NINA or Voyager.

Ardje · Nov 5, 2025, 04:22 PM
So is there any reason to not sell the 294?
Thanks for your advice!

The 2600MM is a great cam, but there is also a need to have a OSC cam as well. Mono cams are great in the winter when you have time to capture a series of filters. OSC cams are more handy in mid summer when there is not time collect a lot of data and multiple channels. OSC is also great for capturing comets as you get all RGB channels in every subframe, whereas the comet will move position between filter changes and it’s harder to process later.

That said, I despise the 294MM and 294MC. The spikey amp glow does not always calibrate away, and correct flats can be hard to obtain. I’d sell that 294MC and get another good OSC, like the 071MC, 585MC or the 2600MC - you’ll be much happier with other choices.