Below is a table of FITS files; each file contains a 'skymap' of the latitude and longitude (in degrees) of the center of each HEALPix pixel. The coordinates for each pixel were computed in Galactic coordinates and converted into J2000 Ecliptic and Celestial coordinates; the underlying projection of these maps still assume Galactic reference frame regardless of the coordinate system reported.
The skymaps supplied below assume a Galactic coordinate projection (matching the skymaps provided by the WMAP team). If your skymap was created assuming a native projection in a different coordinate system, use the Galactic coordinate maps below to retrieve the longitude and latitude of each pixel in that coordinate system.
The recommended download procedure for FITS files is to right click on the file name and select save. Left-clicking on a filename may result in the FITS file being displayed in the browser in an unreadable form.
Coordinates are supplied for seven resolution indices: 4--10. HEALPix supports two pixel ordering systems: nested and ring; coordinate maps for both are provided. A table describing the pixel characteristics at each resolution follows.
The number of pixels in a file is computed from its resolution index (Res).
nside | = 2res | : The number of pixels per side. |
npix | = 12 nside2 | : The total number of pixels in the map. |
HEALPix Pixel Information | ||||
---|---|---|---|---|
Res | NSide | NPixels | Mean Spacing (deg) |
Area (sterad) |
0 | 1 | 12 | 58.6323 | 1.0471976 X 10+00 |
1 | 2 | 48 | 29.3162 | 2.6179939 X 10-01 |
2 | 4 | 192 | 14.6581 | 6.5449847 X 10-02 |
3 | 8 | 768 | 7.3290 | 1.6362462 X 10-02 |
4 | 16 | 3072 | 3.6645 | 4.0906154 X 10-03 |
5 | 32 | 12288 | 1.8323 | 1.0226539 X 10-03 |
6 | 64 | 49152 | 0.9161 | 2.5566346 X 10-04 |
7 | 128 | 196608 | 0.4581 | 6.3915866 X 10-05 |
8 | 256 | 786432 | 0.2290 | 1.5978967 X 10-05 |
9 | 512 | 3145728 | 0.1145 | 3.9947416 X 10-06 |
10 | 1024 | 12582912 | 0.0573 | 9.9868541 X 10-07 |