Simulating the grid lines in Stellarium

Asked by Deven Patel on 2017-05-25


We're working on a project that has led us to simulating the grid lines in Stellarium (Alt/Azi and RA/Dec) in MATLAB. To date, we haven't had much success, we've been trying various spherical equations, but they only seem to work for specific coordinates when we compare it to Stellarium. Are there a set of equations that Stellarium uses to simulate these grid lines?

Thank you!

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gzotti (georg-zotti) said : #1

The appearance of the grids depends on the projection. You may need to implement projections in Matlab.

Deven Patel (deven.patel) said : #2

Yes, exactly, I'm trying to find equations that will return the appearance of the grids for all angles of altitude from 0 to 90 degrees; it hasn't worked so far.

Alexander Wolf (alexwolf) said : #3

Rendering grids for any coordinate system is not sense without the projection.

gzotti (georg-zotti) said : #4

I don't understand the difficulty. Open a math/geometry textbook, or google for e.g. "Sinusoidal Projection" (or whichever projection you want to work with) and the first hit likely is the Wikipedia article about it which usually comes with the relevant equations. Astronomical coordinate conversion (Equatorial/ecliptical/azimuthal) is available from basic astronomical computing literature or likewise Wikipedia. Stellarium's developer team did not invent those projections.

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