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ASI6200 problem

ZWO ASI6200MM Pro Equipment CMOS M16 Messier Objects
Uwe DeutermannAlexJérémieMin Xiewsg
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Uwe Deutermann avatar
Uwe Deutermann avatar
I researched on the internet and could not find any hint on what might be the problem with my new ASI6200. I did the first trial shoots, asked @Gary Imm about his settings (which he insanely fast replied to, thanks Gary!!) and took then in the morning hours a few images of M16 (I wanted to compare with the ASI1600 images that I recently took). And the result was not what I expected. Below the comparison of a single shot (please ignore the defocus with the 6200 for now, that one is a strange one too). Anybody with a suggestion what can be wrong? It almost looks like that it was still set at gain 0. I verified multiple times, at least SGP and APT said it was 100.
Jérémie avatar
Jérémie avatar
@Uwe Deutermann 
Hard to tell from pictures, without actual values : I understand one gives 16bits images and the other 12bits, so if your display normalize the values between 0 and 1, I guess the same number of photons per pixel may note give the same value once divided by the max dynamic range, don’t you think ?

Maybe you need to convert these values into photons / electrons in the same area and compare that ? Or a quick stretch to see if the data is there on the 16bit image.
Gary Imm avatar
Gary Imm avatar
Uwe, related to Jérémie's comment, could you explain how you processed these subs?  The same standard stretch?
Uwe Deutermann avatar
Uwe Deutermann avatar
Thanks @Jérémie for the quick response! I am not quite familiar with any calculations about the photons/electrons, but I do not think that this would make such a big difference. Especially knowing that other people with the 6200 do not run into this problem. Here a STF stretched comparison ... the data is just not there. I am doing right now some comparisons of darks using SGP and ASIImg that comes directly from ZWO. From what I can see (just got 3 so far, so very premature) is that the dark frames with the settings in SGP are darker than the ones taken with the ASIImg program set to High gain. Maybe for some reason SGP and APT do not set the gain correctly? THAT would be a shame, and by now I would have expected someone else running into this problem.
Here the second comparison, STF in PI. Left this time the 6200, on the right 1600. Same exposure lengths (5 min) with Ha
Uwe Deutermann avatar
Uwe Deutermann avatar
Gary Imm:
Uwe, related to Jérémie's comment, could you explain how you processed these subs?  The same standard stretch?

Hi @Gary Imm (so that you get a notice :-))! 

These are the original images downloaded from the cameras, just converted into .jpg (the .fit images look the same). I attached now an STF stretch comparison as well, which tells even more the story. I am now taking darks and compare them: one from SGP, one from ASIImg (set to High gain). Will post that one too soon.

Uwe
Min Xie avatar
Min Xie avatar
@Uwe, 

That's a little strange. I don't have the same experience with both of our 6200s. 
- Did you look into the FITS header to see if the parameters are actually what you set for testing? 
- Could it be the filter? 
- 300s Ha even at 6200's gain 0 has much stronger signal returned.

-Min
Jérémie avatar
Jérémie avatar
@Uwe Deutermann just as a test, in APT or Sharpcap, can you try to record the files on your ASI6200 in 12bits instead of the max 16bits. That way you will output files that are comparable in terms of dynamic range. If they looks similar that way, then it is just a stretching « problem » (ie. you will have to process differently, lowering more the blacks and stretching the mid tones more, to get the same nice contrast you have on your asi1600). If the problem persists, well, we’ll have to dig more :-)

And indeed, can you check the fits header in PI ?
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Uwe Deutermann avatar
Uwe Deutermann avatar
Thank you for checking @Min Xie  and @Jérémie !

Below the result of the FITS-Header, shows 100 as gain.

Jérémie, I can try this out in my next night session, which might take a while since clouds are in the forecast. In the meantime I experiment a bit with the darks, so far no luck.
Personally I do not think that this is a stretching problem, I actually processed the data that I obtained and there is no chance (ok, one never should say no ... but I am 99.99% confident) that I would get even close to the ASI1600 image. I can show this result as well ... 

Alex avatar
Alex avatar
Hello Uwe,

I just received my ASI6200mm, and I only have a couple hours of experience using it.  That said I use APT, and the ASI6200mm seems to work fine with it.  I have not shot narrowband with it yet, and this is my first dedicated astro camera so I have nothing to compare against it.  This is a L sub in APT at 100 gain 50 offset.  My scope is f/4.7 with its reducer and 382mm focal length, so it's a little short for the Leo Triplets.  Really just commenting that to my inexperienced eye that the ASI6200mm seems to work with APT.

With the new camera, did you change your filter setup?  Did you perhaps have the wrong filter selected?  Or as Min Xie stated is there maybe a problem with the filter if it's new?


and the auto stretch preview in APT 
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Min Xie avatar
Min Xie avatar
Uwe, that's indeed strange. Could you try different filters for comparison purposes? For example, compare with either Lum or O3? The first test you posted with Ha filter feels like not much was passed through to the sensor. 

What are the filters for 6200mm and 1600mm?
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Uwe Deutermann avatar
Uwe Deutermann avatar
My "processed" image: well ... just the standard stretch routines, but I kept on going, resulting in an image that I do not want to show even here!!
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Min Xie:
Uwe, that's indeed strange. Could you try different filters for comparison purposes? For example, compare with either Lum or O3? The first test you posted with Ha filter feels like not much was passed through to the sensor. 

What are the filters for 6200mm and 1600mm?

Yeah, I thought first too, that might be the filter. They are the very same that I used with the ASI1600, I do have the Baader Set 2" filters now for more than 2 years. OIII and SII showed the same problems, not as exaggerated as in Hα. I will post one of those as well. Same filter wheel, just set up differently to accommodate the different thread sizes. Both focal distances are identical (55mm), which is the value the WO FLT132 needs with the flattener. Here 2 more examples, the first one M106 with the blue filter (ok, this one is new, from Astronomik, should be fine, used it also with the 1600 for a couple of times. I do not have a direct comparison for this image though, hence hard to judge if this is good enough. If you as me ... it is not. The second one is the OIII channel of M16. Not as obvious in OIII, but I think still very much visible (left:6200/right:1600).

Uwe Deutermann avatar
Uwe Deutermann avatar
Thank you Alex! Your image looks very much from what I expected. I have more and more the feeling that I got a bad 6200 …
Jérémie avatar
Jérémie avatar
This won’t help, but I already like this picture 😀
Seems « flat » : when doing image processing, 32bits images that are not recorded in sRGB (eg recorded « linearly », as the data shows up on the sensor) looks flat as well, and you need to adjust the gamma (equivalent to the midtones slider in the stretch we do in PI) to have them displayed coorectly. Or using Look up tables (LUT). That’s why I was focused on that bit depth problems.
Maybe an option in APT or SGP on what LUT / color space to apply to raw data prior to recording the fits ? Or maybe on the ascom drivers ? Somewhere you setup the camera ?
Maybe drivers issues as well ? I remember you need to install zwo drivers on the computer ? Maybe a specific one for this camera (though they have a one stop shop install if i remember correctly…smile.
Gary Imm avatar
Gary Imm avatar
Something definitely looks off.  Seems like either a driver or a camera issue.  Not much else I can think of, Uwe.  I am assuming you have installed the latest ZWO drivers, which will accommodate all of their models.
Uwe Deutermann avatar
Uwe Deutermann avatar
Jérémie:
This won’t help, but I already like this picture 😀
Seems « flat » : when doing image processing, 32bits images that are not recorded in sRGB (eg recorded « linearly », as the data shows up on the sensor) looks flat as well, and you need to adjust the gamma (equivalent to the midtones slider in the stretch we do in PI) to have them displayed coorectly. Or using Look up tables (LUT). That’s why I was focused on that bit depth problems.
Maybe an option in APT or SGP on what LUT / color space to apply to raw data prior to recording the fits ? Or maybe on the ascom drivers ? Somewhere you setup the camera ?
Maybe drivers issues as well ? I remember you need to install zwo drivers on the computer ? Maybe a specific one for this camera (though they have a one stop shop install if i remember correctly...).

I hear what you are saying Jérémie, but I do not think that this is the main problem. The image itself is pretty bad, and there is no chance to make it even close to this one: https://www.astrobin.com/edgen3/E/?nc=user.
I am not even sure if you can adjust SGP the way you describe, I am just downloading the image and copy it over to PI. I also cannot see why with other settings the data are suddenly appearing. If I would be the first one testing the camera, yeah, I would dig into those specific problems as well, but there are by now many people who use the 6200 and do not experience anything like that, which makes me very suspicious. There is something wrong with the camera I would say, I will contact the dealer today.
Good conversation!!!
Uwe Deutermann avatar
Uwe Deutermann avatar
Gary Imm:
Something definitely looks off.  Seems like either a driver or a camera issue.  Not much else I can think of, Uwe.  I am assuming you have installed the latest ZWO drivers, which will accommodate all of their models.

One never knows when it comes to things like that, I agree, it COULD be a driver issue. I needed to download the newest drivers from ZWO, otherwise SGP would not even detect the camera. And while I was on it I updated the ASCOM platform completely as well. So my feeling is that the camera is defective, at least I do not have any other answer right now. I will contact the dealer today via email and refer to this forum chain.
Min Xie avatar
Min Xie avatar
Uwe, also give a try with NINA. SGP + 6200mm ASCOM driver gave me enough headache (the download stuck issue). SGP won't take ZWO native driver - only ASCOM. NINA takes both.
andrea tasselli avatar
andrea tasselli avatar
It seems to me the a quick way to see what is what is to measure the integrated flus of the same star across the two sets, given that otherwise everything else is (or seems) the same. If the integrated flus is any different from the expected proportions given the differences in QE of the two sensor than something is gone amiss.
Uwe Deutermann avatar
Uwe Deutermann avatar
Min Xie:
Uwe, also give a try with NINA. SGP + 6200mm ASCOM driver gave me enough headache (the download stuck issue). SGP won't take ZWO native driver - only ASCOM. NINA takes both.

Funny that you recommend that, I was already planning to do so. With SGP now asking for a monthly fee I am anyway half way out of the door, just have to see if this program is as good as SGP. I had to install the newest ASCOM driver so that the computer could even recognize the camera, which then worked very well. And ... I am pretty sure that other people (i.e. @Gary Imm ) do not use NINA and have no problems. And the fit image said gain 100 as well, so it cannot be a setup problem. And what about the ASIImg program, that should use at least the ZWO driver, or? Well ... I will find out sooner or later (probably later ...), I contacted already the seller, maybe they have an idea.
Thanks Min for caring, really appreciate it!!
Uwe
Uwe Deutermann avatar
Uwe Deutermann avatar
andrea tasselli:
It seems to me the a quick way to see what is what is to measure the integrated flus of the same star across the two sets, given that otherwise everything else is (or seems) the same. If the integrated flus is any different from the expected proportions given the differences in QE of the two sensor than something is gone amiss.

Thanks Andrea to follow up on this!! As I passed already to Jeremie, I would do all those things if I would be the only user of the 6200, but there are plenty out here by now who should have the same problems, and they do not seem to have it, i.e. Gary, who loves this camera. The difference between the "old" 1600 image and the one of the 6200 is just way too big, the 6200 does not even come close to the 1600 performance. Signal is signal, the processing cannot be a reason, and actually, I tried to do it because I thought that it might be different. So let's see what the seller will say to this, I will not accept the camera as is right now, just have to prove what the problem is.
wsg avatar
wsg avatar
Uwe, I know nothing about narrow band as you know but I just wanted to chime in with my limited experience with my 6200MC.  My camera operated out of the box the same as my 533 and 2600, but there certainly has been discussion about ZWO native gain settings not matching settings on other capture platforms.  However I suspect a gain of 100 should have been a perfectly adequate setting.  Uwe is your comparison to your 1600 results from the same night?  Is it possible your 6200 seeing was very bad?  Sorry if I missed this some where.

scott
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Uwe Deutermann avatar
Uwe Deutermann avatar
Hi Scott!
The images are from 2 different nights, and I agree, this might be a problem with the conditions. ALTHOUGH … this much difference? Never seen this with the 1600, hence I am jumping. I had bad days with the 1600, there is still way more signal than what I see so far with the 6200. 
The M106 image was taken for sure under perfect conditions, and the result was also not encouraging, although … I did not stack the images yet, which I will actually do now. 
Another aspect as well which I did not yet tackle is the focus routine, this resulted in a miserable focus, which I have not seen either so far. Since it was so early in the morning I was not present when that happened, I will definitely look out for this one as well.
Let's see what HPS will say … I still think that there is something wrong with the camera, cannot be such a difference.
The "adventure" is beginning, $4000 and this, yikes, I am a bit frustrated. I am currently setting up NINA to see if this is helping, took already 1 dark file and it does look the same as it did for SGP and ASIImg. 
Thanks for checking in on this Scott!!
wsg avatar
wsg avatar
I have a lot of trouble initiating new gear, especially when it interrupts an image train it took 2 weeks to get right!  I absolutely agree you do not have a processing problem.  The 6200 as well as the other new backlit cameras do have a darker result in the subs that is quite noticeable and is unique but gain 100 and 50 offset are totally normal standards with these new ZWO's in my experience, so you may be right about the camera.

scott
Uwe Deutermann avatar
Uwe Deutermann avatar
Here the newest update, and I will be honest, this is all on me! But it is great to see how many people tried to help, this alone was a good thing about this "nightmare", makes one not feel alone, and we all know, it can be quite lonely under the stars, not many appreciating the wonders of the universe!
So what was wrong, what could have happened that the images of the 6200 were so bad? I took several advices from this thread and tried them out, went all the way into NINA (not bad!!) to use the native driver from ZWO (one never knows), measured some ranges, etc. etc.
This all on Tuesday night where I had a window of a few hours before the clouds came back. Targeted then M51, knowing that I just collected several Hα images of it with the 1600. Making sure everything was set correctly and that the sky was good, since I wanted to pass those bad images to High Point Scientific (they responded within less than a day, nice!) to prove that the camera was faulty.
Got the first images, download them to the desktop (takes now forever with the monster sizes of the 6200), import into PI, star aligned with old 1600 ... and ... identical!!???!! Ok, do the same with some BB filters ... identical!! Sooooo ... the camera could not have been the bad boy, and i was more than happy.
Now the riddle ... what could have "destroyed" the M16 images? Bad weather? No, my guiding is pretty sensitive to clouds, and I would have noticed cutouts then. So the guiding was fine, so must have been not the weather. High clouds? No ... cannot be such a game changer, no way! Had them before and yes, it is worse, but not like that! 
Well ... still not knowing what happened but happy that at least the camera was not the culprit I kept on going. Needed some flats, and since i recently bought a flat panel I did them right away, were anyway clouds. Point the scope to the zenith, put the panel on the lens shade (or whatever this is called) and wanted to start the session when I noticed ... dang ... the shade is retracted!! Well ... yeah, the flat panel is quite heavy and pushed it back. And then I had the answer what was wrong!!! My heating strip is around the lens shade, and when it retracted ... oh yes ... i warmed up nicely the interior of the scope, but NOT the lens!! And of course, when I took the M16 images in the early morning with the greatest dew accumulation and on the first day of  super high humidity in Florida, THAT is the answer. The main scope lens was full of dew, hence the guiding was perfect, hence the image was catastrophic! Slapped several times the back and front of my head, OMG ... and I made so many people think about this, for my stupid mistake. So big apologies for wasting your time, still ... I am very grateful that many were so helpful, something that I do and will not forget!
So: Thank you so much for being there: @Jérémie​, ​@Gary Imm , @Min Xie , @Alex , @andrea tasselli and @wsg !!! You made a difference!
I will post soon my first light, dedicated to all of you!
Uwe

And before I forget: @Vitali , @Iñigo Gamarra gave me advices not through the forum!!!