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Topics - andyc67

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General / Saturated areas
« on: 2017 August 31 13:22:52 »
While processing images from the recent eclipse I noticed something interesting:
The frame in question is a single 1/2s frame at ISO 200 f7.1 of the corona. There is a large area that is saturated as expected.
What I don't quite understand are the following stats of a sample of the saturated areas.

CR2 file no calibration:

count (%)   100.00000
count (px)  107500
mean        65535.0
median      65535.0
avgDev      0.0
MAD         0.0
minimum     65535.0
maximum     65535.0
No surprise there

CR2 file flat corrected only:

count (%)   100.00000
count (px)  107500
mean        56112.135
median      57724.291
avgDev      5694.467
MAD         7432.285
minimum     42047.808
maximum     65535.000

CR2 file flat corrected and bias subtracted:

count (%)   100.00000
count (px)  107500
mean        52290.342
median      54383.518
avgDev      6557.315
MAD         6051.540
minimum     36215.576
maximum     65377.991

So it looks like some of the pixels that have no information because they are saturated, after calibration have an actual value that is below saturation. That is not real information of course.
Can this potentially throw off HDR composition?

General / Deblooming, what am I doing wrong?
« on: 2015 October 24 15:56:49 »
I tried a few times now with no success.
I understand that to remove blooms I have to use HDR techniques. Here is an example of an HDR composition of a stack of 5min subs and a stack of 30s subs. The 30 s subs are not bloomed. This is the best I get. What is the correct way to get rid of blooms?

General / Moving files from CCD Stack to PI
« on: 2015 October 23 17:14:04 »
This has been marginally discussed before. I am trying to debloom my FITs first with CCD stack and then calibrate/process as usual with PI. I have no idea how CCD Stack saves FIT files but I can not make PI work with the output from CCD Stack.
It will work if I save the files in 16 bit TIFF format.
Rather than dealing with figuring out how the FITs are saved I prefer this route. However, are there any downsides to doing this?



General / Max number of subs for image integration?
« on: 2015 August 14 10:28:09 »
Is there a max number of frames for image integration?
If so what is it?


General / Image calibration question
« on: 2015 February 12 08:42:44 »
I see in the image calibration tool for darks flats and bias there is a box that says "calibrate". I am confused on when and if I should check it. Can someone explain to me what the calibrate option actually does?


Pages: [1]