I'm developing a planetarium software and I need the R.A. and DEC that represents every constellation area in the sky. I think I only need R.A. and DEC for each vertex.

Where can I find it?

I'm searching on Internet and I can't find it. Maybe because I'm not doing the right search.

  • 1
    $\begingroup$ I think is here: iau.org/public/themes/constellations. There is a TXT for each constellation with vertex's R.A. and DEC. $\endgroup$
    – VansFannel
    May 29, 2016 at 15:52
  • $\begingroup$ That should be expanded into an answer. $\endgroup$
    – James K
    May 31, 2016 at 16:48

2 Answers 2


James Kilfiger has suggested me to expand my comment as answer, and here it is:

Searching I have found the data in the international astronomical union website. In http://iau.org/public/themes/constellations you can find a TXT for each constellation with vertex's R.A. and DEC.

At the end of that page there is an explanation about the fields on that text files. Their coordinates are J2000.


They are defined on the coordinate grid of 1875; precession has shifted and rotated them since then, and a map for the present epoch must account for that. In addition to the vertices, you may need to interpolate a few points along the edges. Davenhall and Leggett 1989 provide boundary coordinates for epochs 1875 and 2000. For determining which constellation contains a given point, Roman 1987 provides regions and lookup code.


You must log in to answer this question.

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