[PIPE2D-816] Correct for fraction of light from a source entering a fibre Created: 20/Apr/21  Updated: 13/Jan/23

Status: Open
Project: DRP 2-D Pipeline
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: hassan Assignee: rhl
Resolution: Unresolved Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Story Points: 2
Sprint: 2DDRP-2021 A5, 2DDRP-2021 A 6, 2DDRP-2021 A 7, 2DDRP-2021 A 8

 Description   

As mentioned during the 2D DRP tech telecon 2021-04-12: while the 2D simulator takes into account vignetting, it does not take into account the limited fraction of light for a given source that goes down a given fibre.

Consequently, the flux for resolved sources entering a given fiber is overestimated by some 60%. Please fix.



 Comments   
Comment by rhl [ 20/Apr/21 ]

Looking at the ETC source code it'd be easy to port Chris Hirata's C to python; understanding why he did the calculation that way is out of scope. N.b. there's a typo in the manual to make things harder (should be zeta = 4/((1 - upsilon) D) on page 21).

https://github.com/Subaru-PFS/spt_ExposureTimeCalculator/blob/master/src/gsetc.c#L504

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