ASI 1600 Firt Light Reboot-M63

[Rodd]

Thanks to Vlaiv, I got to the bottom of my troubles--Bad calibration due to using optimization of dark frames (scaling) instead of leaving that box unchecked.  So, here is a red stack of M63 using the TOA 130  and ASI 1600mmcool pro, guided with AP Vario Guider and the Lodestar2.  The stack contains:

100 30sec subs and 70 2min subs, fully calibrated.  That sound like allot, but it is only 190min, or 3 hours 10 min.  About what I shoot for in RGB stacks using the KAF 8300 sensor.  Though at F7.7 I found that 3 hours was not enough.  Here as well, allot more data would really help.  This was shot during a 66% (or something like that) Moon, which did not help, but gradients did not bother me as much as I expected--in fact I did not use DBE on this image.  I tried it, but it was better without it.  Once I got calibration to wok--there was no need.

I still lost a bit of FOV (at bottom) due to poor framing, but the primary testing phase is now over, now that I know I can get it to work.  I still need to perfect it--but at least we're moving.   Rotating the camera will be my first step. 2 images are attached.  The natural framing, and a rotated image for viewing as per the norm.  The background appears dark--but the numbers are pretty close to what they should be.  Sky conditions were not great--it was hazy and the background suffers because of it.  I think with more data during better conditions, with no Moon, will allow me to pick up the tidal tail and faint structures known to be around m63.  There is still a problem with fine scale noise--a graininess that appears like black patches, which I minimized by not trying to lft as much of thenouter regions of M63. I think background conditions may be sky related.  

Edit:  Full resolution is a bit shaky still.  But I have run into that before.

 

 

 

[Allinthehead]

Nice start Rodd. First light is all about ironing out the gremlins

[Rodd]

3 minutes ago, Allinthehead said:

Nice start Rodd. First light is all about ironing out the gremlins

Thanks Richard.  We're getting there.

Rodd

[Allinthehead]

2 minutes ago, Rodd said:

Thanks Richard.  We're getting there.

Rodd

I'm gathering first light with my new scope as we speak small issues but making progress. That's the main thing.

[Rodd]

On ‎3‎/‎28‎/‎2018 at 18:00, Allinthehead said:

I'm gathering first light with my new scope as we speak small issues but making progress. That's the main thing.

I see the post--I will have a look.

[Rodd]

Just an update--I managed to collect 96 2 min lum last night.  This is all subs--some of which had high FWHM and eccentricity values and should have probably been left out.  While not a huge crop--a bit more than usual  due to framing issues.  Unity gain, fully calibrated.  Not in lower right corner there is a dark bubble that would not calibrate out.  I used flat darks too.  I shot the flats immediately after shooting the Lum subs and they worked great in al respects but this one thing.  Not sure what it s.

I find the background quite noisy in general with this camera--even when integrating 304 subs (red and lum together).  Could be my sky--but hat is why it is quite dark, because there is a fie scale graininess that I can't deal with n any other way.  Still, for a little over 3 hours, the depth is appreciable. Part of the tidal extensions are clearly seen.  Any suggestions ASI 600 folks?

Rodd

Rotated for normal viewing.  EDIT:  Background very poor.  Not sure its the sky conditions of something else.  FWHM and eccentricity did fluctuate, maybe being an indication of changing conditions.  I don't know.  All I know is there is not a smooth background and its frustrating.  

 

[Rodd]

Here's the best 71 subs of lum only.  FWHM values are noticeably better--stars are smaller.

EDIT:  Don't know if its because I am shooting at F7.7 and using 2 min subs, or what--but again, the background is very grainy--like a checkerboard.  I have seen this with the STT-8300 too but not as bad.  

[alexbb]

That's how the background looks with a CMOS sensor. More subs

And dither. And be careful with the flats. Try to expose to a bright source so that there will be no noticeable noise in the flats.

[Rodd]

3 hours ago, moise212 said:

That's how the background looks with a CMOS sensor. More subs

And dither. And be careful with the flats. Try to expose to a bright source so that there will be no noticeable noise in the flats.

Even with 304 it does not go away (I integrated the red and lum together).  Wow.

Rodd

[alexbb]

I duplicate the layer in GIMP, despeckle it (brightens the dark areas) and blend it as lighten only. That's when I stretch the image a lot.

[Rodd]

9 minutes ago, moise212 said:

I duplicate the layer in GIMP, despeckle it (brightens the dark areas) and blend it as lighten only. That's when I stretch the image a lot.

These sensors are supposed to be super clean......if this is how they are, I don't see the benefit

Rodd

[alexbb]

I don't think there's a big difference between the KAF CCD sensor or the Panasonic CMOS in terms of efficiency. The noise is more random in the CMOS, I believe. That's why you should benefit more with more dithering and more subs with the CMOS sensor. Shoot many calibration frames so the noise in them averages out until only the hot/cold pixels, the amp glow and the vignetting remain obvious. When I shot some flats in low light, I found that they added more noise to the final image. I could have shot some darks to calibrate them, but I applied some noise reduction and blur to them and the final calibrated image came out much smoother. Luckily, I had no dust on the optics so there was only vignetting.

What I observed is that a lot of signal is recorded and it's well above the background noise. You can then compress the lower part of the histogram after you stretched it enough to bring out the faint details.

I don't and didn't own a KAF8300 CCD based camera, but I processed some images. Indeed, the stacks seemed much clearer, but I don't think they contained more signal than a similar stack shot with an ASI1600.

Perhaps you will need to adjust your processing to match the CMOS noise.

[Rodd]

2 minutes ago, moise212 said:

WI don't think there's a big difference between the KAF CCD sensor or the Panasonic CMOS in terms of efficiency. The noise is more random in the CMOS, I believe. That's why you should benefit more with more dithering and more subs with the CMOS sensor. Shoot many calibration frames so the noise in them averages out until only the hot/cold pixels, the amp glow and the vignetting remain obvious. When I shot some flats in low light, I found that they added more noise to the final image. I could have shot some darks to calibrate them, but I applied some noise reduction and blur to them and the final calibrated image came out much smoother. Luckily, I had no dust on the optics so there was only vignetting.

What I observed is that a lot of signal is recorded and it's well above the background noise. You can then compress the lower part of the histogram after you stretched it enough to bring out the faint details.

I don't and didn't own a KAF8300 CCD based camera, but I processed some images. Indeed, the stacks seemed much clearer, but I don't think they contained more signal than a similar stack shot with an ASI1600.

Perhaps you will need to adjust your processing to match the CMOS noise.

Well...I need to finish an image and see I guess.  This is only part of the lum and part of the red! Still, so far I have my doubts.  But another problem is presented in the images below.  There are 3--a calibrated lum directly after integration, a non calibrated lum directly after integration, and a master flat.  It looks to me like the master flat is pretty good and accounts for all the dust bunnies and blemishes.  Why then is there an artifact at lower left that won't calibrate out?  This master flat consists of 60 flats and 60 flat darks.  The histogram is at about 50%

Calibrated lum, 71 2min subs-note blemish at lower left.

Ubcalibrated lum-

Master Flat

[alexbb]

Whoa, I've never had flats so dusty. Maybe one dust speck moved a bit between the lights and the flats?! When I move the camera from one scope to another, I always clean all the filters, the sensor and the last piece of optics as much as I can. After putting all the pieces together, I never take them apart until I'm done with the target I'm shooting. Most of the times, I have no dust bunnies between the sensor and the correcting element and I use the same flats for all the nights.

If I were you, I would clean all the optics before the next session, shoot loads of subs and rely on sigma clipping to reduce the effect of that dust speck in the final stack.

[Rodd]

23 minutes ago, moise212 said:

Whoa, I've never had flats so dusty. Maybe one dust speck moved a bit between the lights and the flats?! When I move the camera from one scope to another, I always clean all the filters, the sensor and the last piece of optics as much as I can. After putting all the pieces together, I never take them apart until I'm done with the target I'm shooting. Most of the times, I have no dust bunnies between the sensor and the correcting element and I use the same flats for all the nights.

If I were you, I would clean all the optics before the next session, shoot loads of subs and rely on sigma clipping to reduce the effect of that dust speck in the final stack.

I do all that too--If you look carefully--all the dust motes line up exatly--even the one in question--it is part of the intersection of several.  Its like it did not fully remove it--but it lines up.  Weird.

[alexbb]

I'm away and only have a dumb laptop with me. I'm afraid I can't do more than just guessing at the moment.

There's one area even darker just a bit above and to the right and that one seems to calibrate out well. My bet would still be that something moved slightly between shooting the flats and the lights, but I don't know how you could accurately check that.

[Rodd]

22 minutes ago, moise212 said:

I'm away and only have a dumb laptop with me. I'm afraid I can't do more than just guessing at the moment.

There's one area even darker just a bit above and to the right and that one seems to calibrate out well. My bet would still be that something moved slightly between shooting the flats and the lights, but I don't know how you could accurately check that.

I shot the flats immediately after the lum....without a filter change.  If that is the case--the data is useless.  If what ever it is moved, I cannot now reshoot the flats.

[Adam J]

That's what it looks like when the dust moves alright. Just crop it out, you can also see if it's only some of the subs it could be that you only lose the early ones as it moved part through the session. The more dust you have the more likely something will move...I have never had anything close to that much dust. 

[Rodd]

9 minutes ago, Adam J said:

That's what it looks like when the dust moves alright. Just crop it out, you can also see if it's only some of the subs it could be that you only lose the early ones as it moved part through the session. The more dust you have the more likely something will move...I have never had anything close to that much dust. 

I just put the camera on and cleaned the filters too.  I had cleaned the filters.  I know I can crop it out (or clone stamp it out more aptly), but the former changes the native resolution as well as reduces the FOV, and the latter is nigh on blasphemy.

[Rodd]

Well--I was finally able to get Mure Denoise to work properly (I had my gain settings incorrect).  this coupled with integrating 304 subs (96 lum and the rest red), I think the background irregularities are becoming less pronounced.  I had to work much less to obtain a smooth dark background while keeping the tidal extensions visible. The test will come after I add 4-5 more hours of lum 92 min subs).  If 8 hours of lum is not enough....the benefits of the 1600 become questionable.

[Rodd]

To end...here is a luminance stack processed as a stand alone mono image.  186 2min subs.  I am having trouble with flat calibration--hopefully I can solve this before going to colored images.  Other than the calibration issue, I am finding this camera to be pretty cool.

Edit:  I added the non rotated image as the rotated one is displayed way too big under full resolution--I don't know if that's the camera or the rotation.  We'll see when I check this out after I post it. 

2nd Edit:  Still to big!  The image looks OK under regular viewing, but at full resolution viewing its just way too much.  I have always used full resolution as a way to check to see if I am processing well, but maybe with this camera that is not applicable.  Don't know.  All I know is full resolution mode is terrible

[Adam J]

Rodd, 

I just purchased a ASI1600mm-pro from FLO a week or two back....if it ever comes back into stock I may even receive it one day. 

My research says that its important to use a pedestal with this camera or you can get black clipping. 

It may be a processing artifact but you do seem to have a scattering of black pixels. Why not post a dark frame?

Cheers, 

Adam

[Rodd]

4 minutes ago, Adam J said:

Rodd, 

I just purchased a ASI1600mm-pro from FLO a week or two back....if it ever comes back into stock I may even receive it one day. 

My research says that its important to use a pedestal with this camera or you can get black clipping. 

It may be a processing artifact but you do seem to have a scattering of black pixels. Why not post a dark frame?

Cheers, 

Adam

How do you use a pedestal?

[Adam J]

12 minutes ago, Rodd said:

How do you use a pedestal?

Well that indeed is the question, I cant say I have ever done this myself as I don't have the camera yet, its something Jon Rista on cloudy nights recommends and involves telling Pixinsight / APP to increase the value of all pixels by a fixed amount prior to integration to prevent them from being black clipped following calibration. 

Here is a link:

https://pixinsight.com/forum/index.php?topic=2182.0

You don't say what gain you are using?

[Rodd]

3 minutes ago, Adam J said:

Well that indeed is the question, I cant say I have ever done this myself as I don't have the camera yet, its something Jon Rista on cloudy nights recommends and involves telling Pixinsight / APP to increase the value of all pixels by a fixed amount prior to integration to prevent them from being black clipped following calibration. 

Here is a link:

https://pixinsight.com/forum/index.php?topic=2182.0

 

I don't think the pedestal issue is what is wrong with my flats.  I need to fix that first before I try something a drastic as this.  It would be good to here some input from some more experienced ASi1600 users before I start to tinker in this way.

Rodd