Account for Earth's occultation

[israelmcmc]

Currently out algorithms do not account for the Earth's occultations, blocking a fraction of our FoV. It might not be critical for DC2, since the instrument is pointing at zenith, but once you include rocking then e.g. 2 same SC attitude direction do not give you the same response across the field of view

[israelmcmc]

Notes from cosipy meeting:

• @hiyoneda : We first need to update the SpacecraftFile class to return the SC location in Earth coordinates (#215)
• @hiyoneda points out that for DC3 we can also use another workaround. Since the orbit will be Equatorial, and the SC will point at discrete directions —e.g. +-20° from the orbital plan, the Earth will only occult a discrete set of areas in the FoV
• @lommler Jan pointed out that this might actually be close the real scenario. Need to determine how much it deviates if the orbit is perfectly equatorial
• @israelmcmc : leave as a last resource option

[israelmcmc]

• By the October meeting:
  • Have a way to account for Earth occultation, even if it is slow
  • We mainly need to go back to use time bins instead of scatt bins.
• For DC3:
  • Attempt to make it as efficient as possible. Maybe there’s a nice trick?
  • We should retain scatt bins to some capacity. Still useful to reduce some trigonometric operations.