Hi everybody !
I use a QHY163M for LRGB/LRGBHa, and i am wondering if it is a good idea to upgrade to a 294MM cam.
Thanks a lot !
I use a QHY163M for LRGB/LRGBHa, and i am wondering if it is a good idea to upgrade to a 294MM cam.
Thanks a lot !
294MM vs 1600MM
Hi everybody !
I use a QHY163M for LRGB/LRGBHa, and i am wondering if it is a good idea to upgrade to a 294MM cam.
Thanks a lot !
I don't know, i have QHY163M, and i then bought/added ASI1600MM, and then i was planning to get QHY294MC but i got the mono version from the seller, i can't say i will get rid of QHY163M, but it shows a lot of issues or showing age or i didn't clean it since long time which means i will depend more on ASI1600 and the new one 294mono, but i won't give up my QHY163M yet, 294 mono is much better and worth the upgrade.
Hello !
It depends on the setup you have. Overall the 294M is a great camera.
There are two big difference : the QE and the pixel size.
- The quantum efficiency is a lot higher on the 294M, at about 90% vs 60% for the 1600, which is a 50% improvement so you are definitely going to feel it.
- The pixel size if smaller on the 294M at 2.3 vs 3.6. So if you have a wide scope or plan to do planetary it might suit you but if you have a long focal length you might have to binned it and you will lose some SNR compared to a camera with larger pixels. ( A quick note here, the 294M is sold as a 11Mp but it really is a 48Mp camera that is binned in 2x2. Because it is a CMOS, your SNR only improve by x2 when binning 4 pixels together compared to the x4 improvement on CCDs or on a camera that has two time bigger pixels. On the QHY294M you can access the 48Mp mode, I'm not sure about the ZWO)
- I'll will also add the amp glow that is not smooth compared to the 1600 but easily manageable with darks.
Hope this helps
It depends on the setup you have. Overall the 294M is a great camera.
There are two big difference : the QE and the pixel size.
- The quantum efficiency is a lot higher on the 294M, at about 90% vs 60% for the 1600, which is a 50% improvement so you are definitely going to feel it.
- The pixel size if smaller on the 294M at 2.3 vs 3.6. So if you have a wide scope or plan to do planetary it might suit you but if you have a long focal length you might have to binned it and you will lose some SNR compared to a camera with larger pixels. ( A quick note here, the 294M is sold as a 11Mp but it really is a 48Mp camera that is binned in 2x2. Because it is a CMOS, your SNR only improve by x2 when binning 4 pixels together compared to the x4 improvement on CCDs or on a camera that has two time bigger pixels. On the QHY294M you can access the 48Mp mode, I'm not sure about the ZWO)
- I'll will also add the amp glow that is not smooth compared to the 1600 but easily manageable with darks.
Hope this helps
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I have/used both ZWO camera versions, i.e. 1600MM & 294MM.
The ZWO asi294MM operate also in bin1.1-mode, at a resolution of 8288*5644 and pixel size of 2.3 um.
Right, there is amp glow in 294MM, but a master dark frame will take care of this issue.
A M51 5min Ha exposure is shown here before dark/flat calibration, the camera is in bin2.2 mode,
http://www.dl.dropboxusercontent.com/s/2hxhn5czkcm6cco/ObsRemoteDesktopLabtop1-7-4-2021.jpg?raw=1
The ZWO asi294MM operate also in bin1.1-mode, at a resolution of 8288*5644 and pixel size of 2.3 um.
Right, there is amp glow in 294MM, but a master dark frame will take care of this issue.
A M51 5min Ha exposure is shown here before dark/flat calibration, the camera is in bin2.2 mode,
http://www.dl.dropboxusercontent.com/s/2hxhn5czkcm6cco/ObsRemoteDesktopLabtop1-7-4-2021.jpg?raw=1
I am having serious difficulties working with focus, in canon or samyang lenses (135mm or 200mm), in asi294mm. The zwo adapter did not work, even with the extender. Any suggestion?
Thanks in advance.
Thanks in advance.
I tried to put the QHY294M with the ZWO filter on the Samyang 135/F2 but I couldn't because of the short backfocus, contrary to the standard 55mm backfocus, those on DLSR lenses are shorter, 46.5mm in my case with a Nikon mount. And if your backfocus is longuer, you can't focus to infinity.
ricardo leite:
I am having serious difficulties working with focus, in canon or samyang lenses (135mm or 200mm), in asi294mm. The zwo adapter did not work, even with the extender. Any suggestion?
Thanks in advance.
Have a look at the ASCOM Canon Lens Controllers from Astromechanics. Worked great for me.
I upgraded to a 294mm from a 1600mm. It’s a definite but small “upgrade” and it’s not without its flaws, contrary to the hype others might have for it. It exhibits strong banding in narrowband, the darks also overcompensate. 4 people in my group and 6 294mm cameras and we can all agree with this. If I were to “upgrade” again I would go to the 2600mm instead. Currently not worth it for me. All in all it’s a good camera but it’s not great. Also something to note, the native pixel size is 2.315, the pixel size of 4.63um is basically software binning so when people talk about pixel size… you can 2x bin a 183 or a 1600mm if you want bigger pixels which will effectively give you a bigger well and higher dynamic range. No different than what a lot of these bigger pixel cmos are doing. They get you excited about well depth and quantum efficiency but that’s what binning will do for you. All of that drops when you go to the native pixel size
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It exhibits strong banding in narrowband, the darks also overcompensate. 4 people in my group and 6 294mm cameras and we can all agree with this.
I am using an ASI294MM Pro for half a year now and I noticed none of these problems.
Well Written
I'm in agreement with Matt… The 294mm is better than the 1600 in my experience but not without some issues. In my case, I'm having a little bit of trouble with flat calibration and that has never been an issue with the 1600.
I have not used this at the unlocked bin 1x1 mode as of yet because I am currently working at longer focal lengths. I do intend to use bin 1x1 with HyperStar and a short refractor in the coming months.
I have not used this at the unlocked bin 1x1 mode as of yet because I am currently working at longer focal lengths. I do intend to use bin 1x1 with HyperStar and a short refractor in the coming months.
Olaf Fritsche:It exhibits strong banding in narrowband, the darks also overcompensate. 4 people in my group and 6 294mm cameras and we can all agree with this.
I am using an ASI294MM Pro for half a year now and I noticed none of these problems.
You probably wouldn’t know it to see it.
I had 4 1600mm and sold them for 4 294mm. Regretted it almost immediately. All 4 of my 294 experienced pretty severe horizontal banding in narrowband. Nothing I did was able to prevent it. In addition, the amp glow never calibrated out cleanly. Everyone I know who has the 294mm has the banding issue to some degree and imo is unacceptable for a camera that is so expensive. The 1600mm on the other had is a proven camera and never gave me a single issue. For that reason I can never recommend the 294mm to anyone.
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Thank you very much for your answers. 
I think i will keep my QHY163M. The ASI 2600MM seems to be a great cam. Unfortunately, the price is definitely not the same.
In fact, i need the 4/3 version of the ASI 2600MM. Such a sensor does not exist, i imagine.
Clear sky !!!
I think i will keep my QHY163M. The ASI 2600MM seems to be a great cam. Unfortunately, the price is definitely not the same.
In fact, i need the 4/3 version of the ASI 2600MM. Such a sensor does not exist, i imagine.
Clear sky !!!
I would imagine a 4/3 mono version will happen eventually. Tbh, I traded my 4 294mm for 2 IMX571 (2600mm and 26m) and it was the best decision I ever made. If I were you I would consider doing whatever possible to save up for one of those you won't regret it.
These banding issues are concerning to hear about. I just moved from a 1600MM to the 294MM. I've only been able to take about 15 test frames in HA 3nm, didn't notice any banding in that limited test but probably didn't stretch really hard either. The amp glow was frightening compared to the 1600 but it did calibrate out fine with darks so I was relieved. No issues with flats on the HA filter but the flats are more mottled looking than what I'm used to. They seem to work fine though with my lights.
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These banding issues are concerning to hear about. I just moved from a 1600MM to the 294MM. I've only been able to take about 15 test frames in HA 3nm, didn't notice any banding in that limited test but probably didn't stretch really hard either. The amp glow was frightening compared to the 1600 but it did calibrate out fine with darks so I was relieved. No issues with flats on the HA filter but the flats are more mottled looking than what I'm used to. They seem to work fine though with my lights.
In my research I found that it doesn't effect all units but definitely a number of them. ZWO hasn't acknowledged the problem but QHY did. However, QHY claimed it was only an issue at low gains and if you use unity gain or higher its fine but that's definitely not true as everyone I know who has the problem was already using unity gain or higher including myself. I think it's just a bad batch of sensors personally.
i cant compare the 294mm to the 1600 as it's my first mono camera. I'm Very happy with the results. It has more amp glow than other cameras I've used, but i find nothing that doesnt calibrate out with simple flats. darks and bias. I've used it exclusively in narrowband (3.5nm) and no issues at least when using it in 2x2 bin mode and using exposures long enough to really swamp any pattern/read noise... 300s seems to do the trick. I think there's a lot of fiddliness than can add to variable experience and reports... i had a day scratching my head with some rubbish stacks when I realised that my flats (from NINA) had defaulted to 1x1 bin...that's something to watch for. Anyway proof is in the pudding ...here's a few from the last month.
https://astrob.in/5pkch9/B/
https://astrob.in/5te3pk/0/
https://astrob.in/t0wg2k/0/
https://astrob.in/qzgch0/0/
https://astrob.in/5pkch9/B/
https://astrob.in/5te3pk/0/
https://astrob.in/t0wg2k/0/
https://astrob.in/qzgch0/0/
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My thoughts are one's success with the 294MM in narrowband may have much to do with the type of telescope you are using. I hit a wall with my C925Edge HD when trying to do SII lights and flats (master flat attached). This may have to do with the intensity of light from the secondary, but I could never find a way to soften the flats by lower exposure time, lowering ADU from 30K down to 2K, or by trying other binning levels. I also tried a number of light panel adaptations with several layers of cloth, etc. Whatever I tried there was a bright disc in the center of the SII flats and they were not useable to calibrate the lights. How the 294MM may work with refractors or Newtonians, I do not know. My LRGB flats and lights were basically OK. Ha and OIII showed some sensor mottling patterns, but I could work with them with some difficulty.
SII_30K_Master_Flat.jpg
SII_30K_Master_Flat.jpg
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I agree that its a small upgrade… but the difference is noticeable.
In regards to banding with narrowband.. in my case it was resolved by exposing longer. 10 min NB subs at gain 120 in my bortle 4 skies yielded no banding. The banding was present with 6 and 7 min subs.
In regards to banding with narrowband.. in my case it was resolved by exposing longer. 10 min NB subs at gain 120 in my bortle 4 skies yielded no banding. The banding was present with 6 and 7 min subs.
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James is that with 1x1 or 2x2 binning? I find 5min enough with narrowband and 2x2 to flatten any noise. But probably depends on speed of system. That's at f4.5. And I'm more light polluted at 6/7 so that probably helps.
I tried up to 10 min subs and it made no difference on any of the 4 I had.
This now will turn to another thread of 294 mono banding issue, i didn't test mine, and even if it has whatever issues there i will not give up it or return it because i got it new at very cheap price, same price of a color, so i will live with it then, and i do have QHY163M and ASI1600 and later will buy APS-C color, means i shouldn't just use 294 mono for everything and anything, and if it is a narrowbanding that is the problem then i will use it at lower gain then, but who know, i have to test and use it more and see.
James is that with 1x1 or 2x2 binning? I find 5min enough with narrowband and 2x2 to flatten any noise. But probably depends on speed of system. That's at f4.5. And I'm more light polluted at 6/7 so that probably helps.
2x2 binning.
Yea.. results will vary on a lot of variables. In this case I'm at F7 in a bortle 4.
I'm using it with my Edge 8 so I'm not planning to run it at 1x1... unless I move the camera to a different scope.
Tareq Abdulla:
This now will turn to another thread of 294 mono banding issue, i didn't test mine, and even if it has whatever issues there i will not give up it or return it because i got it new at very cheap price, same price of a color, so i will live with it then, and i do have QHY163M and ASI1600 and later will buy APS-C color, means i shouldn't just use 294 mono for everything and anything, and if it is a narrowbanding that is the problem then i will use it at lower gain then, but who know, i have to test and use it more and see.
"Another" That implies something to say the least.
You can live with something and acknowledge its flaws, see marriage.
We should be trying to remedy it or ditching them for better sensors.
I have no attachment to any brand, I'm in this to do the damn best I can do and I'll throw something in the garbage in a heartbeat and move on if its getting in my way of that.
Tareq Abdulla:
This now will turn to another thread of 294 mono banding issue, i didn't test mine, and even if it has whatever issues there i will not give up it or return it because i got it new at very cheap price, same price of a color, so i will live with it then, and i do have QHY163M and ASI1600 and later will buy APS-C color, means i shouldn't just use 294 mono for everything and anything, and if it is a narrowbanding that is the problem then i will use it at lower gain then, but who know, i have to test and use it more and see.
"Another" That implies something to say the least.
You can live with something and acknowledge its flaws, see marriage.
We should be trying to remedy it or ditching them for better sensors.
I have no attachment to any brand, I'm in this to do the damn best I can do and I'll throw something in the garbage in a heartbeat and move on if its getting in my way of that.
It is same when that ASI1600MM and equivalent cameras such as QHY and Atik versions with Panasonic sensor resulting into that microlensing issue, i saw few people who gave up on those cameras and went back to CCD, so i know how people always react with any issue or defect or wrong with any item, be it a camera or a mount or a telescope, i am not that kind of people who just give up, i know we all looking for perfect items or perfectionism, but that doesn't mean i have to damn an item model somehow, many talked about Takahashi scopes and some of them are just crap or not perfect parts they came with, so it makes me feel like Takahashi doesn't care to make all of their models as top quality because of the brand name.
Bottom line is, if any model has flaws and we throw it away it means we don't gave those manufacturers any chance to improve, or to fix things, so if that 294 mono is bad for you then you tell others to get something else if they have to stay away, what else they can get then? ASI1600 is an old outdated model, and something like 2600MM/268M are expensive for others at $2000, so it is like you forcing people either to spend that much or stay with an old model, or you just put them at difficult situation about acknowledging the issue of this camera model, i can't get APS-C mono, and i have Panasonic sensor cameras, so if i should go with those what else mono there to get? 183 i don't like much.
I got the camera before knowing about that issue, and i don't feel like i have to always get rid of my things because i find out later or late that it has issues, as i said, i have to test it first, if i can't solve the issue at all then i have two three options, one is to use it with filters not presenting the issues which means LRGB i think, two is to live with the issue, and last three is to get rid of the camera completely and losing my money, i don't know what another options are there for me or others to follow who are in same my situations and can't afford larger sensor mono camera.