Hi L2 - Update how full spin helio frame maps are produced

[subagonsouth]

Algorithm Description:

From Dan's email:

Hi All,

I agree with Sungjun’s summary below, and I’ll note that it applies to L2 as well. I went over the Lo CG algorithm and realized that it doesn’t explicitly discuss the case of combining data from ram and antiram parts of the sky, because this is not something that the Lo team plans to do (they only make ram maps). I should have caught this when reviewing for Hi, so my apologies for not catching that. We can discuss this at the meeting, but I believe we will need to make sure that we first create CG-corrected ram and antiram maps separately and then combine them. I can think of at least two reasons:
A key step in the CG correction is finding the mean spacecraft frame (SF) energy to associate with the PSET bins that contribute to a heliospheric frame (HF) map pixel for a given HF energy Eh. This makes sense as long as the PSET bins are generally close in angle wrt the SC velocity vector (and therefore close in Es). However, if combining PSET bins from the ram and antiram directions in the same pixel, then the values Es will be quite different. In particular, for the ram bins Es > Eh and for the antiram bins, Es < Eh. Thus, using the mean value for these violates the assumption that is close in energy to the individual Es values.
As I argued for the L3 combinations, in general the ram observations have better stats for viewing a given part of the sky than the antiram observations, even if the exposure time is the same, just because we collect more counts. Thus, w should combine these after building ram- and antiram-only maps using uncertainty weighting.

Therefore, the Hi HF map construction will need to be modified some. Sorry Tim!!

Regards,
Dan