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Messages - Starcruiser

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1
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 October 02 16:40:56 »
Quote from: Starcruiser
Well my last ditch attempt as an experiment was to acquire all new -10C darks last night and make a fresh master from those and see how that goes running it on a group of just three lights and see of the problem is gone with ImageCalibration module.
And what was the result?
Were the lights at -10C?

Hi, thanks for checking in.  Went ahead and reacquired a new set of -10C darks and bias, made the new masters from them and applied them to several of the earlier problematic -10C lights.  All appears to be in order.  Not sure what caused my earlier difficulties but we seem to be good to go.--Thanks.

2
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 29 14:17:07 »
Well my last ditch attempt as an experiment was to acquire all new -10C darks last night and make a fresh master from those and see how that goes running it on a group of just three lights and see of the problem is gone with ImageCalibration module.



3
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 28 13:14:49 »
something must have changed - is it a new dark master you are working with?

no correlation means that IC scaled the dark down incrementally and repeatedly subtracted the scaled dark from the light, and found no minimum in noise. this usually happens when the lights are so short that they exhibit almost no dark signal. what is the duration relationship between the lights and dark in your case?

rob

Thanks.  I am using 10 min lights with 10 min darks.  Over two days I have made several new dark 10 min. masters, the problem only gets fixed in CCDStack for the calibration phase and extract the color channels.  After that I bring it all back over to PI so I can get something done on this job.  I am starting to wonder if something has gone sour with my ImageCalibration tool.

4
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 28 13:06:51 »
Quote
Because after calibration the subs are covered with the identical hot pixels

Sometimes yes, but ImageIntegration (rejection algorithms) usually takes care of them. Try WinsorizedSigmaClipping.

HTH.

Best regards,

Enzo.

Thanks, but thats what I have been using.

5
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 28 08:53:20 »
For a CMOS camera you probably want to turn off dark optimization.

Cheers,
Rick.

Thanks but I tried that earlier in the game.  Did not fix any of this.

6
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 28 08:52:04 »
Quote from: Starcruiser
Second screen shot:

What makes you think the calibration refuses to apply the dark?
If I understand those screenshots correctly, scaling factors of around 0.94-0.95 are being applied to the dark.  That is almost 1.0 i.e. very similar to a straightforward subtraction of the whole dark.
The bit to look for in the Process Console or the log file is where it mentions the dark scaling factor:
e.g.
Dark scaling factors:
t0 = 0.939

Mark

Because after calibration the subs are covered with the identical hot pixels which match up similarly to the dark master.  When calibrated in CCDStack this does not occur.  This behavior did not happen until after the first time I got this message a couple days ago: "** Warning: No correlation between the master dark and target frames" and those subs likewise were full of hot pixels as it is my understanding the master is ignored in such a case.

Now I don't get the warning and everything is as shown in my screen shots and the subs are not worth integrating after calibration.  Yes I see what you mentioned about the scaling factors being applied but the results sure don't show it.  After spending hours over two days doing this over and over I gave up and did the calibration in CCDStack.  I don't remember having this issue with PI in the past until now.

Thanks for your response.

7
General / Re: Image Calib Refuses To Apply Dark
« on: 2018 September 27 12:45:50 »
Second screen shot:

8
General / Image Calib Refuses To Apply Dark
« on: 2018 September 27 12:43:51 »
Been trying to get to the bottom of this for two days.  Gave up and did Preprocessing in CCDStack.  Acts as if the dark is ignored in PI.  Here are two screen shots of my settings.

9
General / Re: Mouse Over Info
« on: 2018 March 29 07:48:05 »
Hi Bernd,

Ah I see now.  Seems my mistake was hovering over the pulldown window instead of hovering over the pulldown window label side.

Thanks,
Bill

10
General / Mouse Over Info
« on: 2018 March 28 12:51:12 »
Is there a way to increase the mouse over info panel where all the help information can be read?  A lot of it is clipped at the bottom and cannot be seen.  At least I have not discovered it.

Thanks,
Bill

11
General / Re: GREEN Channel Vertical Banding
« on: 2018 March 26 07:23:34 »
The effect that Rob decribed is not confined to narrow band filters and can occur with RGB filters or OSC cameras as well. Did you check the calibrated frames as I suggested? If clipping is the cause, it will be obvious in the histograms (of the green channels).

Bernd

Green did have an odd weak histogram so I ended up restarting at the beginning and all looks well.

Thanks,
Bill

12
General / Re: GREEN Channel Vertical Banding
« on: 2018 March 26 05:04:51 »
For "The Pacman Nebula" image no narrow band filters were used. Did the current problems occur with the use of narrow band filters?

Take a look at the histograms of the calibrated frames (monochrome camera) and the calibrated, debayered and channel-extracted frames (OSC camera). Compare red and blue vs. green channel. If the green channel of one camera is clipped severely, Rob will be right. In this case a wrong calibration (e.g. pre-calibration of the dark frames or the MasterDark) may be the cause. However, if the calibration was well, the measures that Rob suggested will put things right.

Bernd

Hi Bernd,

I am not using narrowband filters with this run either.  It looks at this point I may very well be better off starting out from the beginning and hopefully things will fall into place.  Don't want to tie folks up chasing one gremlin that may very well be operator error.  With the lousy conditions for image acquisition over the previous year I get infrequent use of PI, so it seems I am always starting over but I have had some successes with it.  Dual rig imaging does complicate things a bit but it does increase the yield for the available sessions.

Thanks for the input from  all.

Regards,
Bill

13
General / Re: GREEN Channel Vertical Banding
« on: 2018 March 26 04:47:02 »
the moire pattern / crosshatching effect in narrowband images can be due to the lack of background signal in narrowband images. the background is too near the dark signal and during calibration some pixels would be negative after calibration, and so are clamped at 0.

that can be avoided either by making longer exposures, or adding a pedestal to the calibrated files such that there are no negative values and thus no 0 values in the calibrated frames.

rob

No narrowband was used.  The OSC calibrated and debayered files were likewise combined with the RGB files of the mono camera albeit different image scales in StarAlign.  Exposures for both cameras was 300 secs.  Only the Green debayered channel acts up when aligned and scaled with the mono camera green channel.  Red and Blue do fine, so it is unexplainable at this point why Green cannot do as well with the same process.

Thank you for your input,

Bill

14
General / Re: GREEN Channel Vertical Banding
« on: 2018 March 25 15:25:09 »
Just for an experiment, try aligning the green subs WITHOUT calibrating them first.  I know that sounds crazy but I bet it "fixes" the problem.  If it does then we have a different direction to investigate.  I sometimes run into just this problem with narrowband images and simply have to do a work around of ImageCalibration by cleaning up the subs/image with CosmeticCorrection, ImageIntegration, and DBE.

Let me know if that helps at all.

Jim

I can certainly  try that but I am so used to calibrating the OSC prior to debayering so I am not sure where that will lead us.


15
General / Re: GREEN Channel Vertical Banding
« on: 2018 March 25 15:22:40 »
I am sorry, then I have no idea what goes wrong here. Hope that Jim's suggestion will be helpful.

Bernd


Yep this doesn't make any sense for me either.  Why can't PI process the Green just like it did Red and Blue instead of messing it up?

It worked great for this run:

http://www.kd0npt-astro.net/images/ngc281-lrgb_1435x1080_dualrig.html

Only difference now is I am using a QHY168C in place of the STF8300C on the 80mm scope.  Should only be a difference in the scaling calculations to me.


Thanks for the attempt!

Bill
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