ctools

So far the csviscube only has a Sun constraint. A moon constraint should be added.

In the CTA scheduler, Pep Colomé mentioned that they take into account the sky brightness as a function of Moon altitude, Moon-target distance, and Moon phase.

So far there exists a moonzenith parameter that is however not yet used. It looks like a parameter that limits the sky brightness would be more appropriate. A moon model can for example be found in Britzger, D. (2009) (studies of the Influence of Moonlight on Observations with the MAGIC Telescope. Diploma thesis Universitat München. https://magicold.mpp.mpg.de/publications/theses/DBritzger.pdf). An alternative an simpler moon model can be found in 1991PASP__103_1033K.pdf.

According to https://arxiv.org/pdf/1704.00906.pdf, MAGIC observations are typically done up to 12 times NSB_dark, where NSB_dark are the NSB conditions towards the Crab with no moon in the sky.

A much more simple scheme is used in SSTillumination.pdf. Here, the fractional lunar illumination (FLI) is used, which is fraction of the lunar disk that is illuminated at local civil midnight. In ESO standards, lunar dark time is when FLI < 0.4. Nevertheless, even if the moon illumination is small, a minimum distance to the moon should probably be respected (the MAGIC paper speaks about 20 deg). Hence it would make sense to add to more parameters to csviscube:
- moondist: the minimum distance from the moon
- flimax: the maximum allowed FLI