HEALPix, nested, res 8 (Nside=256)
Original Data Source
The Wisconsin H-Alpha Mapper (WHAM) made a survey of H alpha intensity over the full sky with a 1 degree beam and velocity resolution of 12 km/s. The WHAM public data release DR1 includes a data product containing H alpha intensity integrated between -80 and +80 km/s LSR velocity for each observed sky position. The Centre d'Analyse de Données Etendues group used these data to form an all-sky HEALPix format map following the method described in Appendix A of Paradis et al. 2012, A&A, 543, 103, ADS. Their HEALPix map is provided here. LAMBDA made a new version of their FITS file with minor changes to the headers to make them compliant with FITS standards.
From the WHAM public data release website:
When using the survey data, please add an acknowledgment to the effect of:
The Wisconsin Hα Mapper and its Hα Sky Survey have been funded primarily by the National Science Foundation. The facility was designed and built with the help of the University of Wisconsin Graduate School, Physical Sciences Lab, and Space Astronomy Lab. NOAO staff at Kitt Peak and Cerro Tololo provided on-site support for its remote operation.
More details can be found in:
"Early Results from the Wisconsin H-Alpha Mapper Southern Sky Survey", Haffner, L. M., Reynolds, R. J., Madsen, G. J., et al. 2010, in The Dynamic Interstellar Medium: A Celebration of the Canadian Galactic Plane Survey, ASP Conference Series, Vol. 438, p. 388, ADS
"The Wisconsin H Alpha Mapper Northern Sky Survey", Haffner, L. M., Reynolds, R. J., Tufte, S. L., et al. 2003, ApJS, 149, 405, ADS