Haslam 408 MHz Data ProductsThe first file listed below contains HEALPix format data stored in a binary table extension, and its FITS header is linked to in the File Info column. The HPX file contains the same HEALPix data stored as a 2D primary image array in HPX projection (Calabretta and Roukema 2007), and may be displayed with SAOImage DS9. For the convenience of users who do not require the capabilities that HEALPix offers, we also provide the maps in two projected image formats: Mollweide and Zenith Equal Area (ZEA). These files contain the string "_mollweide" and "_zea" respectively, and may be displayed with standard astronomical display software such as DS9 and SAOImage. Note that the Mollweide and ZEA image pixels typically over-sample the HEALPix pixels, thus some amount of data replication will be present in the image data. As a result, care must be taken when using the image data in a regime where the noise properties are important since the statistical weight per pixel will also be replicated. The HPX files are celestial maps with a FITS-standard HPX coordinate system. The process is described in "Mapping on the HEALPix Grid" by Mark Calabretta and Boud Roukema; see http://www.atnf.csiro.au/people/Mark.Calabretta Recommended download procedure for '.fits' or '.tar.gz' files:
| |||||||||||||||||||||||||||||||||||||||||
