I'm parsing FITS files for a project based on data from a telescope. These files include 'DEC', 'RA' and lat long values. I understand roughly the concept of celestial coordinates and I assume that these values are sufficient to calculate the direction that the telescope is facing and the angle that it's at but my trigonometry is not up to the task.

I am using astropy for the project so any answers which reference that would be great.

  • $\begingroup$ What do you need to calculate? DEC and RA are the celestial coordinates, so they are "where" the telescope is pointing at. $\endgroup$
    – Envite
    Commented May 21, 2014 at 10:34
  • $\begingroup$ In order to determine the position of the telescope relative to the earth from RA and declination, you need to know the latitude and longitude of the telescope and the date and time. *** A new question by a different user, @ruadath, has appeared here astronomy.stackexchange.com/questions/2507/… . You might want to track that question. $\endgroup$ Commented May 21, 2014 at 19:32
  • $\begingroup$ Especially, if it is a space telescope, it is a mess :) you need much more than two coordinates. $\endgroup$
    – Py-ser
    Commented May 23, 2014 at 5:16

1 Answer 1


PyEphem will get you Alt, Az from RA, Dec, Lat, Lng, Date, Time, and Elevation http://rhodesmill.org/pyephem/


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .