Taking flat images for color cameras

[Astrofriend (Lars)]

Just a few days before Christmas, today I felt it was a good day to do something about my flat images. It has always been a problem. With color cameras there is a need to have the three color channels at the same signal level as the camera sensor see it. If not it can be that one color channel oversaturate and another one get too low and get noisy.

I have used a monitor where I can adjust the color and other stuff, no one was easy to use. Now I building one with a RGB LED stripe with some extra control of the colors.

Interesting ? You have photos and text about my DIY here:

http://www.astrofriend.eu/astronomy/...libration.html

This is the one that worked best yet. But I have to develope it more now when I know I can use it. The 3D-printer will come in use again.

Merry Chrstmas to all of you !

/Lars

[Astrofriend (Lars)]

I had some problem with my 3D-printer and this DIY Flat frame box fell asleep. Now I started it again and have got some very promising result. The key to it is the LED stripe which can be fine adjusted in its color.

Note:
This is only interesting for color cameras. like my DSLR camera.

Here are the details of the project with text and photos:
http://www.astrofriend.eu/astronomy/...alibrator.html

It's working now but I 3D-print some new details that correct the small details.

/Lars

[bojan]

I am taking flats in BW on sky before photo-session.. no problems with that (and DSS).

[Astrofriend (Lars)]

Hi Bojan,
Yes that was what I did earlier too, it worked well. But now I want to take it to a higher level. No variations of the level from image to image. Sky flats have a tilted background which I want to eliminate. Most important, have the same level of each color, no one saturate and no one at too low level.

Most of my astrophotos is taken from a heavy ligth polluted sky. It's much easier to process these images if I do a flat calibration of a high quality. Then I separate what's caused by the optic and by the light pollution.

When I process my images I background subtract each sub image. It works better if the vignetting is eliminated before. Background=subtract, Vignetting=division.

Why make life easy when it can be done much more complicated. :-)

Bojan, which Borte Class do you have at your place ?

/Lars

[bojan]

Originally Posted by Astrofriend

... which Borte Class do you have at your place ?

/Lars

In Ballarat (Mt Pleasant) it is now ~6, Melbourne (Mt Waverley) is close to 8...

[Astrofriend (Lars)]

Hi Bojan,
That's better than I have, Bortle Class 9 where I live. But if I take the car and drive 40 minutes to the coast I have a relative dark view to the East, Bortle Class 4 at best.

/Lars