Astroart Forum

I've been successfully using AA5 to process FIT file images from my SXV-H9C. I recently purchased AA6 and cannot get my raw images to properly color combine using the "Preprocessing" routine. I've spent several hours trying to figure out which "Options" settings to use... and all I get are garishly colored blue, red or yellow combined FIT files!

In particular, when I check "Demosiac RGB" in the options section, AA6 does not display any preferred selection in the "Pattern" box of the "RGB Demosaic" window. It simply shows all 4 pattern options with a 25% setting on each. Although I can apparently highlight any of the 4 options, I cannot change the 25% setting. According to the AA6 Help file section explaining the "RGB demosaic" options, AA6 should automatically select the correct option and setting for my SXV-H9C... Right?

Can someone please tell me how to properly designate and set the appropriate "Pattern" option in the "RGB demosaic" window within the Preprocessing "Options" section? I would also appreciate receiving advice on which "Color synthesis Algorithm" to apply. At this point, I see no value in upgrading to AA6. Thanks for any help.
Dave M.

Hello, just like in AA5 before enabling the "Color Synthesis" in Preprocessing, you should (only one time) setup the parameters manually, opening an image and clicking Menu Color / RGB demosaic. The realtime preview will allow to setup the parameters correctly. The parameters will be automatically saved to disk, then it will be possible to use the Demosaic in Preprocessing without setting them.
The 25/25/25/25 likehood means that it's not possible to find out the correct X/Y offsets from the Preprocessing window (since there is not an image), in AA5 this is shown graphically as 4/8 gray squares in the "Image" panel.

To emulate the basic White Balance option in the Astroart 5 Color Synthesis, use:

White Balance:
-Algorithm: None (*)
-Bias: RGB

(*) later, change this to make a even better white balance.

Thank you for your responses to my query. I did as you advised and applied RGB demosaic to a single raw FIT frame. The procedure generated a new FIT file with a C prefix, which I saved to my raw FIT folder for the object. When I went back to Preprocessing and selected all my raw image frames and dark frames, the "Demosiac RGB" option did not display the settings generated by my separate processing of the FIT file with the C prefix. This leads me to 2 additional questions:

1) When I generate the RGB demosaic of the single frame, which "gray" shades in the 4 pattern boxes (i.e. light gray, mid gray & dark gray) equate to R, G & B. I assumed that light gray = blue, mid gray = green and dark gray = red... is this correct?
2) Must I generate a separate RGB demosaic file with a C prefix for each of my raw FIT files and then use these as my selected image files in preprocessing?

What I would really like to find is a U-Tube video or printed document that explains how to fully process my raw images from the SXV-H9C (or similar OSC camera) using AA6. Is there such a video or document available? Thank you again for the advice you have given and any additional advice you might offer.
Regards,
Dave M.

1) Hello, not exactly, just like in AA5 they are only a hint to find the correct X/Y offset for unknown images. Sometimes the red is darker than blue. In AA6 the X/Y offset are represented by the four buttons. In all my H9C images the correct button is the upper-right (it may be different only if the images were saved vertically flipped).

2) No, that would be time consuming and would not take advantage of the automatic proprocessing.

3) Actually the procedure is very simple, just setup the Preprocessing like a grayscale image (dark/flat/align etc.) and enable the option RGB demosaic, for all my H9C images I simply use:

X/Y Offset buttons: The upper-right one.
Color synthesis: 1x1 bilinear, any other is good.
White balance: Algorithm None.
White balance: Bias RGB

Actually the only important option is the correct X/Y button.
All the other options can be set more or less randomly, since after the Preprocessing it's required to open the window "Color Curves" anyway to tune the color channels.
So, the other options are just useful to get a nice-looking image after the Preprocessing, but this is not required to obtain a correct result, since the Color Curves allow to fix the bias and stretch of the channels in all cases.