[Stellarium-pubdevel] How to implement alternate lat/lon grid?

[Shriramana S. <sa...@gm...>]

Hello. I'm a student/researcher of traditional Indian astronomy where
the longitudes of bodies are given w.r.t. a zero point diametrically
opposite Spica i.e. so that the longitude of Spica is fixed at 180°.

I would like to use Stellarium to illustrate the movement of the
planets with this grid of reference displayed as an alternate to the
ecliptic of date. I realize I will have to tweak the precession code
for this (IIUC).

Please guide as to where in the code I should dig to find this. I have
downloaded the 0.16.1 tarball.

Thank you!

-- 
Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा