Hi Greg,
PixInsight is able to read and write virtually any valid FITS file.
Supported features include:
- 8-bit unsigned integers.
- 16 and 32-bit signed and unsigned integers.
- 32 and 64-bit IEEE floating point.
- Grayscale and RGB color images.
- Unlimited number of alpha channels.
- Embedded ICC profiles, metadata, color space and resolution data.
I would like to see one of these FITS files that you cannot open in PixInsight. Could you please upload some of them to a website and post the address here? Also, what error message(s) are you getting when you try to open them?
Thank you.