I believe I found the problem. Raw recording was set to High efficiency (star). I changed it to Lossless compression and it works fine.
Thank you for the quick reply! Here's a link to the RAW file: https://drive.google.com/file/d/18W4ZTnrBdipIN92cDaEFY1tF05vEOq2P/view
I tried stacking RAW files taken with my Nikon Z8 running firmware 3.10. Under Stack method, Raw conversion is set to LibRaw (full active area). I add my lights (NEF file format) and click Analyse and organise images. It appears to work fine, but then the result column fills with No FiTS! and the bottom output section says Converting <file path=""> to FITS file format.</file> I gave full disk access to astap (MacOS) and ran the program with administrative rights (Windows 11), but the result is the...