Dark File Woes from Altair Hypercam 183CProTec

[CThody]

Hi

I've been trying Pixinsight for three days now and cannot get it to remove the starburst from my images (created by the amp glow in my 183C). I read that others are having similar problems - would appreciate any advice! The attached image is from my latest attempt, after following a few different tutorials to use the batch preprocessing, integration and then removing the background colout. The starburst is still present on the right of the images :-(

Any ideas most welcome!! Thanks in anticipation.

[pfile]

make sure your dark durations match the light durations exactly, and don't check "optimize" in the master dark section of BPP (or the ImageCalibration process, if you are using that)

rob

[CThody]

Hi. Thanks - do you mean the exposure time of each frame or the total number of dark frames should also match total number of lights?

[pfile]

sorry - i was talking about the light/dark subexposure duration. the total exposure time of the dark does not necessarily have to equal the total exposure time of the lights... you just need enough darks so that the SNR of the master dark frame is strong.

also i forgot to mention that since you won't be optimizing (scaling) the master dark, you don't need bias frames.

rob

[CThody]

Thanks Rob. It still doesn't work :-(

[pfile]

are you sure the gain is the same between the darks and the lights?

how about the offset?

rob

[CThody]

All settings are identical.

[txo]

The same problem here. I tried everything. When optimization and calibration is turned off it only helps a bit. Doesn't remove the starburst completely however. I tried it just with darks and lights. exposure time, gain, temperature was the same.

[Geoff]

I doubt that amp glow is the cause. Looks more like the flare from an out of field star—probably one of the belt stars. In which case darks won’t do anything.
Geoff

[pfile]

some cmos sensors do exhibit this weird starburst thing at the edge of the field - if it's in the darks that's what it is.

but there's no reason why it should not calibrate out, so in this case maybe it is a flare? impossible to know without seeing the darks.

rob

[txo]

I doubt that amp glow is the cause. Looks more like the flare from an out of field star—probably one of the belt stars. In which case darks won’t do anything.
Geoff

No it's not. It is real cmos starburst. And it looks like there is a problem in pixinsigth or my workflow. But I can't even find any new relevant switches I haven't tried already.

It would be nice if someone from inside pleiades astrophoto took a look on this. This is not only my problem judging from other posts on the internet. Common advices are do not use PixInsight...

[STEVE333]

It is real cmos starburst. And it looks like there is a problem in pixinsigth or my workflow. But I can't even find any new relevant switches I haven't tried already.

It would be nice if someone from inside pleiades astrophoto took a look on this. This is not only my problem judging from other posts on the internet. Common advices are do not use PixInsight...

If this is a real cmos starburst problem, then, I would expect it to be present no matter which image processing program you are using.

Are you saying that you have processed the same data with another image processing program (not PI) and the starburst is not present?

If I understand your explanation , this sounds like a data problem not a PI problem. I'm not defending PI. Just trying to understand your problem.

Am I missing something?

Steve

[Juan Conejero]

As always: We cannot help without a sample of the data where problems can be reproduced, analyzed and described. Sorry, we don't have crystal balls. So if you want to help us solve an issue related to specific data, or possibly a bug (damn, I am not perfect, sorry), then we need the specific data. Or a crystal ball, at your option.

Let's try the first option first. Can you upload a complete and sufficient data set where this problem can be reproduced consistently (dropbox, etc)? Thank you so much in advance.