Update of COLORTYP

[Gary Hawkins]

I've been using ASTAP to extract R, G, B colors from a file captured with a color CMOS camera. When the extracted file is created, the COLORTYP remains as RGGB. Should this not be updated to "", indicating a monochrome file?

[han.k]

Hi Gary,

I was not aware such keyword exists. Which program write this keyword into the header? I tried to follow this standard:
https://cdn.diffractionlimited.com/help/maximdl/FITS_File_Header_Definitions.htm

The type of image is defined with keyword Naxis and Naxis3. For three colours Naxis changes fr om2 to 3 and Naxis3 from 1 to 3. something like this

NAXIS = 3 / Number of dimensions
NAXIS1 = 4048 / length of x axis
NAXIS2 = 2764 / length of y axis
NAXIS3 = 3 / length of z axis (mostly colors)

So the three dimensions are length (1..4048) , width (1..2764) and color (1..3)

But for green extraction the image should always be a raw image. Which is a in principle a gray image. This raw image has an header like this:

NAXIS = 2 / number of data axes
NAXIS1 = 4144 / length of data axis 1
NAXIS2 = 2822 / length of data axis 2

Han

[Gary Hawkins]

Hi Han,

Thanks for this information.

I'll look further into the definitions and get back to you with questions. Thanks for the great work on ASTAP.

Happy Holidays,

Gary