I am currently concerned with automatic download & processing of SLSTR data products, so it would be useful for me to automatically distinguish night products from day products. I know there is a DAY mask in the list of masks available with the SLSTR data structure, but I would like to know if there is also a simple flag for it. I hope someone can help me @marpet
You can just check the adquisition time over your area of interest and check which products are during night. If you are over Europe in UTC zone you have it easier.
I hope this helps
Maybe the gropundTrackDirection metadata attribute is helpful: