My 1st run with the Asi 1600mm pro / mini5 efw lrgbHa

[stepping beyond]

This is an awesome edition to my arsenal but, it's going to take a lil' while to get used to framing my targets to get the most out of it.  Orion nebula in different colors yall 's thoughts to improve on this?

[vlaiv]

53 minutes ago, stepping beyond said:

Orion nebula in different colors yall 's thoughts to improve on this?

Most basic way of doing this would be:

In daylight take a piece of white paper and place it some distance away from telescope so you can aim your telescope at it and reach reasonable focus (does not need to be 100% accurate focus - just enough so you know what is the paper and that you are aiming at it). Pick a sunny day but don't let paper be in direct sunlight - but rather in shade.

Shoot R, G and B images of this paper with same settings - exposure time needs to be the same. Make sure you don't clip any of images (like when shooting flats). Measure average ADU in each image.

Record following values:  mean_G_adu_value / mean_B_adu_value - we will call that B_scale and

mean_G_adu_value / mean_R_adu_value  - we will call that R_scale

Now that you have B_scale and R_scale - each time you shoot a target after you stack your data but before you start processing it - multiply R channel with R_scale and B channel with B_scale to get color balanced image.

Another approach would be to use color checker chart - and shoot that instead and derive color transform matrix, but that is a bit more involved.

[stepping beyond]

Thank you Vlaiv, when I do shoot my flats doesn't need to be perfect focus right ? I've not really had any success adding the flats I took with my Asi174mm cool but, darks an bias performed in CCDstack 2 maybe do to not clipping in curves and levels in PhotoShop cs I really need to learn this flats process and my images will improve immensely in theory. I shoot my flats in my basement  {cave section that has black plastic over the windows blocking all stray light  using a T-shirt doubled up and a  15" light panel sitting in a chair somewhere from 2 feet away,  I focus until I start getting  get dust donuts . I remove the camera from the scope every night and it's never been in the same position even with marks and focus every channel each time I'm out . 2020 and so far this year haven't been good for imaging but, I'm taking this time for advancement in astro image processing  These do not have any calibration added , 2nd and 3rd have been stretched to the oblivion . I use Sgp for all my  equipment and Dso aquisition . I'll work on this hopefully with alot of luck . Ronnie

Edited March 20, 2021 by stepping beyond

[vlaiv]

23 minutes ago, stepping beyond said:

Thank you Vlaiv, when I do shoot my flats doesn't need to be perfect focus right ? I've not really had any success adding the flats I took with my Asi174mm cool but, darks an bias performed in CCDstack 2 maybe do to not clipping in curves and levels in PhotoShop cs I really need to learn this flats process and my images will improve immensely in theory. I shoot my flats in my basement  {cave section that has black plastic over the windows blocking all stray light  using a T-shirt doubled up and a  15" light panel sitting in a chair somewhere from 2 feet away,  I focus until I start getting  get dust donuts . I remove the camera from the scope every night and it's never been in the same position even with marks and focus every channel each time I'm out . 2020 and so far this year haven't been good for imaging but, I'm taking this time for advancement in astro image processing  These do not have any calibration added , 2nd and 3rd have been stretched to the oblivion . I use Sgp for all my  equipment and Dso aquisition . I'll work on this hopefully with alot of luck . Ronnie

For flats you really need to keep infinity focus that you used when shooting lights.

Best way to take flats is to do it at the end of the session before you strip down everything. Just take flats without changing anything to setup after you finish collecting the data (hopefully mini EFW is reliably repeatable).

It might be worth investing into proper flat panel? Diy solutions are not that expensive - you need LED strip and piece of mat acrylic window to act as diffuser.

Alternatively - you can purchase ready made unit. I'm using one of these:

It is no longer made in that shape - they have new model now:

https://www.teleskop-express.de/shop/product_info.php/info/p8241_Lacerta-LED-Flatfield-Box-with-240-mm-usable-Diameter.html

(however, it is now much more expensive - in reality it is something like $10 worth of parts put together and that is why DIY is so much cheaper).

If you search google for DIY flat field light box - you'll get a lot of interesting suggestions - like this one:

http://www.astrosurf.com/comolli/flatfield2.htm