Hello everyone,
I have looked at several datasets from Pier 14.
I have the same problem with all datasets. The flats have overcorrected.
So far I have always been able to solve this problem by doing a DBE.
Does anyone else have this problem, or am I doing something wrong?
CS
Darius
Hi Darius,
Yes we have been working on this issue and have managed to figure out the cause and a solution.
The cause is down to the gain settings we were trialling on Pier 14. We set them to the values suggested for Deepsky by ZWO. It does work but then creates a much more noticeable variation in the bias pixel values, the variation is inherent in CMOS cameras.....
The short answer there is pretty easy fix, this can be done in two ways by adding a pixel value to your Master Flats in Pixel Maths or when calibrating your flats before stacking to create your master, simply add a Pedestal value of 200 or above. Both methods will reduce the over correction of your light frames.
In truth the values are quite low and can be easily resolved with DBE as you suggested.
The long term fix it to set the Gain value back to our standard dynamic gain setting and will be implementing this in the coming weeks. We have paused the new jobs in the job queue to allow the ones that have already started to finish, there are only a few jobs to complete now and once done we will change to the new gain setting and do some fresh calibration frames.
Hope this answers this for you.
regards
Peter