Take the tour ×  How does one draw a star chart like this?  I
have:    1. a star database with coordinates (right ascension -
RA, declination - DEC),   2. observer coordinates (latitude,
longitude) and   3. time of observation.  I need a formula which
considers these parameters (mapping star coordinates to a 2D
image). e.g.  starX = (90-abs(DEC)) * cos(RA)  starY =
(90-abs(DEC)) * sin(RA)  share|improve this question add comment
1 Answer  Try starting with this page from the US Naval
Observatory. The formulas are pretty simple and give you azimuth
and elevation. The star chart you linked is basically a polar
plot then, with the azimuth being the angle of the plot and (90
- elevation) being the radius.  share|improve this answer add
comment  Your Answer