How can the Solar Azimuth Ground be calculated from NAC footprints information?


This might be a stupid question but I would like to calculate automatically the Solar Azimuth Ground from information contain in the NAC footprints ( a bit as it is done in PILOT, if you open the information tab of a specific NAC image. I see that there are some information about the incidence, emission, phase, subsolar azimuth angles, subsolar latitude and longitude, and more in the thumbnails (but no solar azimuth ground). Can somebody point me in the right direction in how this is calculated (equations)? I tried to have a look at PILOT’s GitHub repo but I can not find it anymore on the USGS GitHub.

Thanks for your help,
Best regards,
Nils Prieur

Found some information in an old post (at and

This values are computed from the unprojected imagery. You can find the exact math in the ISIS sensor model code

There is a more basic reference in the glossary USGS Isis: Glossary

Thanks for your help, I will check those resources :slight_smile: