[Kstars-devel] Proper Motion Corrections - The Right Way

[Akarsh Simha]

Hi

With James' great_circle_destination() routine, it was very easy to
get the right Proper Motion corrections. After some playing around
with the subroutine, things seem to be working out correctly.

I notice a very significant drop in the number of copies, and a drop
in the slope of the straight line that approximates the
scatterplot. Also, the scatterplot now looks more closer to a straight
line at high PM values. I don't know whether this is reasonable and
what the reasoning behind this might be, though. I'm hoping this is
reasonable because the cos( delta0 ) term in the old formula is now
gone, which could've caused the number of copies to come down.

Is there some way of verifying the validity of these results?

Please find a scatterplot of Copies vs. PM (milliarcseconds / yr)
attached. The green plus marks are for the old formula
(flat_trim.dat) and the red plus marks are for the new formula
(spherical.dat)

Regards
Akarsh
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