Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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|cite|improve this question

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|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.