Master flats

[DarrenS]

I have captured some T shirt flats, testing new filters.
 
As the light was fading each exposure has slightly different levels, would normalization be required to compensate for this?

thanks
Darren

[Cleon_Wells]

Darren, check this link out that Juan posted in the PixInsight thread.
http://pixinsight.com/tutorials/master-frames/en.html

Here is an example of a MasterFlat I created this morning after sun up. 12-Canon T1i CR2 subs,  iso400 @ 1/125.

Cleon

[DarrenS]

thanks for that Cleon 

Suprised to see how much difference there is betwen the two flats.

Do the dark and bias calibration frames need to be matched to the flats in anyway?

Darren

[Cleon_Wells]

Darren, I would check out this post that Juan added to.

http://pixinsight.com/forum/index.php?topic=3240.0
and Vicent’s
http://pixinsight.com/tutorials/master-frames/en.html


I’m still trying to get a handle on IC and Enigma  and have tried many combinations. On July seventh I acquired more subs of M63 with the Moon lighting the way. 8>) The subs are all @ iso400 and 120sec with 35sec between shoots with the Canon T1i. The first subs were at 27 degrees C and with the IC dark scaling factors in the 0.5 range, 2 hours / 48 subs later the chip temp went up 5 degrees C and the IC dark scaling factors for this temp are in the 1.0 range. I had to increase the DSLR raw Brightness level to 2.5 before I ran IC to get these scaling factors, otherwise the scaling numbers were in the 0.2 range with the DSLR raw Brightness level at 1. I should try increasing the Brightness level to 3 or more and get the dark scaling range averaged around 1.0. Note ,I can increase my DSLR raw brightness level to 4 before I clip the subs because the Canon T1i creates a 14bit raw file which relates to a 0.25 fits camera clip point.

“Do the dark and bias calibration frames need to be matched to the flats in anyway?”

I try to use Darks with the same iso and time and temp, the temp is a moving target with the DSLR as my example show a 5 degree change over 2 hours. My Bias subs are at iso400 and 1/4000, my Flat subs are at iso400 and 1/125 for this last test. I assume my need to increase the DSLR raw Brightness level for IC is caused by my relative bright MasterFlat.

“”””Disclaimer, I don’t know what I’m doing….LOL””””
Cleon