The WHAM Sky Survey is available as two datasets. The first is a kinematic release containing more than 49,000 spectra covering the whole sky revealing Galactic Hα emission between roughly -100 to +100 km/s (LSR) with 12 km/s velocity resolution. The second dataset contains only the velocity-integrated (-80 to +80 km/s LSR) intensities of these pointings. As a convenience, the kinematic release contains the integrated dataset in separate fields.

You can browse a sample of the WHAM-SS through a set of pre-generated figures. These are suitable for use in presentations or posters with proper attribution.

Release Versions

Public releases are tagged with a major label (DR#), a survey version (YYMMDD), and a revision date (YYMMDD). The initial release is labeled DR1. Using these designations, the base name for public survey files follows: wham-ss-LABEL-vVERSION-RELEASE. For example, wham-ss-DR1-v161116-170111 is a file generated on 01/11/2017 from the DR1 survey base version 161116. See the documentation below for more details.


This document describes the WHAM-SS and the format of the data. Each data file also includes a README in the header or in an IDL variable. Please read them carefully before contacting us with questions.

Kinematic Survey (DR1-v161116-170912)

  • IDL SAVE [89 MB]
  • FITS Binary Table [87 M]
  • FITS Cube [gzip, 359 M] (Interpolated, Regular Grid)
  • *** NOTE: The FITS cube (only, not the IDL or FITS binary table) from the 170317 release was missing a final scaling factor (from instrument units to Rayleighs). Intensities derived from that cube need to be divided by 22.8 for the units to be in Rayleighs. Or, rerun analysis using the newer releases above.***

Integrated Survey (DR1-v161116-170912)

Release History

DR1-v161116-170111 : Initial public release.

DR1-v161116-170222 : Add integrated survey release in FITS image format. Tweak data file header documentation.

DR1-v161116-170317 : Add kinematic survey release in FITS cube format. No changes to other formats.

DR1-v161116-170912 : Fix scaling in FITS cube format. No changes to other formats.

(The original northern-only survey release (NSS) is still available but is superseded by this release. It will no longer be updated and will be retired soon.)


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