smudges on post processed image

[squreshi786]

Hi
I have a canon dslr and use PI to calibrate with lights/darks/bias and flats. Unfortunately my end results has smudges on it and can't get rid off.
I take flats using either backyard eos or sgpro, don't know if I am taking wrong flats. Take with IPAD and using Backyard eos I go for half or 1/3rd histogram from left. If using SGPro, I have tried a mean ADU of 8800, 12456 and 25698 but the smudges are always in the same spot with no change. Could anyone advise.

Thanks

[ngc1535]

Generally the issue with flats is the handling of the bias.
If your camera has a bias level- then you need to subtract the bias from the flats.  (presumably your data was calibrated with your darks... and these had the bias it).
All of this before debayering of course. In the past BPP has done a good job for me on OSC files. However, I haven't done any super long exposures with my Canon DSLR.

(no one else was answering this thread... so I am throwing something out there)

[bulrichl]

Just one idea: you mentioned different image acquisition software, BYE and SGP. Please make sure that you use always the same file format for the raw frames, in case of a Canon camera, preferably CR2.

FIT format is not well standardized. I know that SGP (when you choose FIT format) scales the intensity data. I don't know what BYE does. Mixing frames in FIT format from different image acquisition software might give rise to problems.

Bernd
 

[squreshi786]

Thanks

But the reason I mentioned about BYE and SGPro is because i was struggling to get rid of these black smudges which i initially though were dust and put it down to issues with flat. i was using supra for its flat calibration tool to work out the correct exposure length but recently used the FLAT COU=NTOUR PANEL SCRIPT which showed me that it doesn't coincide with the black dead areas. So I don't know what are these ? dead pixels??

Saqib