Detailed Integration Documentation

[Cleon_Wells]

For those that haven't gone to    http://pixinsight.com/doc/tools/    , like me, check out
Juan's Reference Documentation on ImageIntegration.
Why doesn't the statement  "Normalization is an absolutely necessary previous step to pixel rejection" apply to calibrated dark subs?
Cleon

[astropixel]

Hi Cleon. Normalisation of flats is automatic as far as I know. Can you educate me as to the reason for normaliziing darks?

[Cleon_Wells]

Rowland, I don't have any answers all I have are questions...8>)
Remember when I had to put an Output pedestal (DN) of 10 in Calibration to get a set of 15 DSLR Dark subs calibrated  and then integrated into a MasterDark with out Pixel Rejection Normalization to work  properly. I found I could get these 15 Dark subs to work with a Calibration Output pedestal (DN) of 0 if I used Scale+Zero offset Normalization in Pixel Rejection.
It could be that the read noise of the 120sec iso400 Dark subs  was to low and after MasterBias subtraction the Calibrated Dark sub level was to close to 0, maybe..........
These same 15 Dark subs converted to  .fit and integrated with No Normalization create a unCalibrated MasterDark, this MasterDark with the (cal box) check in Image Calibration works, go figure....
Cleon

[astropixel]

These same 15 Dark subs converted to  .fit and integrated with No Normalization create a unCalibrated MasterDark, this MasterDark with the (cal box) check in Image Calibration works, go figure....

Had the same problem a while back and fixed it the same way - associated with darks of ~60 - 120 seconds. It drove me nuts not to mention anyone who was unfortunate enough to reply to my posts. In the end, it came down to lots more frames. I don't know what PI does in these cases. Hence, my catch cry - take more darks... Yet I have used as few as 3 darks (of 30 seconds), bias and flat frames and they worked fine ...as you say, go figure...?

I keep coming back to the conditions under which calibration frames are taken and recency to light frame acquisition - temperature differences...

[Cleon_Wells]

Rowland

If you are interested here is a camera I'm in the process of butchering aka modifying - perhaps it will take better darks. Can't wait to run few through PI. BTW I have installed an Astrodon Inside filter in this camera too - waiting to take some shots and see what gives calibration wise.

Be careful with the pc board mounted ribbon connectors, make sure you have released the lock bar on each connector. I had some issues with one of mine when I wanted to see (under the hood) so to speak, I almost broke one of these mini ribbon connectors.....
Also there's an issue with getting the CMOS sensor  square with the OTA optics, I just tighten all three screws down against  their support springs and hoped for the best.
I'll start a new thread concerning this Dark sub calibration issue.
Cleon

[astropixel]

Stay with this one. I've removed the superfluous comments. Didn't mean to hijacked the thread.