healpy/healpy — pull request #69 by PaulPrice (2012-12-06 19:47:45+00:00)
Title: Add python-level support for get_ring_info and pix2ring

Another one, pure-healpy this time. I fear this will conflict with #68 (because different code has been added in similar places), but the resolution should be straightforward (order of inclusion shouldn't matter).

Motivation: for Hyper Suprime-Cam, we want to represent the sky with tangent planes positioned on HEALPixels. The most space-efficient way of doing this is to rotate the tangent planes 45 degrees so they're oriented like actual HEALPixels. But it seems some astronomers are conditioned to expect that north is up, and in that case this becomes very inefficient. If we skip every other ring, however, we might be able to have the best of both worlds.