I am trying to decide on a camera to mate to my 9.25 for galaxies and have narrowed it down to the the 294 mm and the 2400 mc. Not that much difference in price when filters are factored in. Would the better specifications of the 2400 out-weight the inherent advantage of the mono 294 ? thanks
dennis michels
The OSC option is the easiest to deal with and the mono is the more performing at the expense of added complexities. I deeply doubt the largish field afforded by the 2400 is any use with galaxies unless you plan to use FR (highly recommended) so that the 294 still has a respectable FOV. If you ask me I'll go with the OSC option any day.
Thanks andres, I do plan to use a .70 reducer (at least some times) with the 9.25. I did not even think in terms of FOV when considering this camera choice. These two cameras both have big pixels, low read noise, deep wells and a large FOV. Do you see that last thing a draw-back.
Big field with small galaxies isn't the best rendering fro them, if you ask me. You'd want the galaxies to stand out, not lost in a large field of sparse stars. You can always crop for sure, but if the camera is just dedicated for that it would be a waste of money. In the end is your choice. Just make sure you don't oversample your typical seeing, as I see so many do.
Thanks andres, I do plan to use a .70 reducer (at least some times) with the 9.25. I did not even think in terms of FOV when considering this camera choice. These two cameras both have big pixels, low read noise, deep wells and a large FOV. Do you see that last thing a draw-back.
The 294 doesn't have big pixels, it is binned 2x2 by default to make for the advertised 4,63 µm pixel but they really are 2.3µm.
Hello Pablo, I see that ZWO is marketing the 294mm as having a pixel size of 4.63 that is for sure. Is the binning information in the fine print? This would seem to put the 294 as quite average for galaxies however on Astrobin it seems to be the camera of choice. The waters are getting murky.
2400 mc 294 mm
pixel size 5.94 4.63
resolution 6072x4042 4144x2822
full well 100Ke 66Ke
read noise 1.2-6.4 e 1.2-7.3
qe 80% qe 90%
2400 mc 294 mm
pixel size 5.94 4.63
resolution 6072x4042 4144x2822
full well 100Ke 66Ke
read noise 1.2-6.4 e 1.2-7.3
qe 80% qe 90%
Hola andres, So if I don't want to oversample I should not get a camera with small pixels for a scope with a native FL of 2500. If Pablo is correct that the 294 is actually 2.3 then it is oversampling compared to the 2400. Your other point seems to be that i should not spend money on sensor size not needed for Galaxies, who would argue with that. So what camera should I get for the 9.25, the 2400 in spite of the waisted sensor size?
The 294 is fine at its default settings of 4.63 microns. That additional mode (2.31 microns) is in reality aimed at the planetary imaging concerns. You should really simply ignore it. As I would do (I have the colour version of the 294). You should really looking at the correct sampling for your seeing (and only you can answer the question but use the 3 px per FWHM rule) and the second is the field width, so that at your native FL you get to field width what you want. If it fits M101 with some room to spare then probably it is going to be all right in the day. Just make sure that the field you are covering is well corrected. No point in throwing money at poor field coverage. I might also suggest you look at the ASI533 and see how this one would fit your needs.
Thanks andrea, I will be using this set-up in the back country of Wyoming at 7000' asl my bortal is around 2 and seeing is great except for the wind. Correct me if I am wrong on this, the higher the FL the bigger the pixel, but the better the seeing the more you can reduce that FL driven pixel size. If this is correct then I think that the perfect pixel size is around 9. So unless I go with a CCD any CMOS is going to be a over sampling compromise to some degree. Seems to me if the 2400 came in a mono version then it would, on paper, be the best CMOS camera ( zwo offers) for faint small objects using a FL of 2350. I am not factoring in cost with this opinion. Since the 2400 only comes in color then it would be reasonable to say it is the best color camera for this type of fig. If this can be agreed on then is the 294 the best mono for this same purpose.
Hello Pablo, I see that ZWO is marketing the 294mm as having a pixel size of 4.63 that is for sure. Is the binning information in the fine print? This would seem to put the 294 as quite average for galaxies however on Astrobin it seems to be the camera of choice. The waters are getting murky.
2400 mc 294 mm
pixel size 5.94 4.63
resolution 6072x4042 4144x2822
full well 100Ke 66Ke
read noise 1.2-6.4 e 1.2-7.3
qe 80% qe 90%
Hello Denis, yes what I meant is that the sensor on the 294MM is a 47Mp pixels with 2.3µm pixels, but by default when you plug the camera it gives you a binned output to make it for the 4.63µm.
On the QHY294M you can acces the 47Mp mode and I think you can also now on the ZWO with their latest driver.
I'm not completly sure why they do that but I think I remember reading somewhere that there was no mono sensor available from sony that had the same pixels size and resolution as the 294MC so they took this one that has exactly 4x more pixels, binned it and advertised it as a mono version of the 294MC.
Now what I think is important here is that being a binned 4.63µm pixel, and because it is a CMOS, you will have more read noise and less SNR than if it was a native 4.6µm.
So if you don't plan at all to use the 47Mp mode, maybe this is not the right camera for you.
That said, I own a QHY294M and I am very pleased with it, I use the two reading modes depending on what i'm imaging and I think it's a very versatile camera.
Hope this help
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Thanks andrea, I will be using this set-up in the back country of Wyoming at 7000' asl my bortal is around 2 and seeing is great except for the wind. Correct me if I am wrong on this, the higher the FL the bigger the pixel, but the better the seeing the more you can reduce that FL driven pixel size. If this is correct then I think that the perfect pixel size is around 9. So unless I go with a CCD any CMOS is going to be a over sampling compromise to some degree. Seems to me if the 2400 came in a mono version then it would, on paper, be the best CMOS camera ( zwo offers) for faint small objects using a FL of 2350. I am not factoring in cost with this opinion. Since the 2400 only comes in color then it would be reasonable to say it is the best color camera for this type of fig. If this can be agreed on then is the 294 the best mono for this same purpose.
If I were you I would go for the 2400 option in bin2 mode most of the times and when the seeing is really great (I mean below 1.6-1.8") then switch to bin1 mode, if the subject is bright enough.
Thanks Guys for the thoughtful replies. We all use many sources for information and of course Astrobin is one of them. When i look at the best imaging using a rig similar to mine i see that by far the ZWO294 mm is the most used camera. Could this just mean that this was perceived as the best camera by the best astrophotographers 2 years ago when that decision was made and not indicative of what these folks would choose today.
When i spot someone on Astrobin who is doing what i am aspiring to do can i just ask them for advice? I guess i will look into that.
When i spot someone on Astrobin who is doing what i am aspiring to do can i just ask them for advice? I guess i will look into that.
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