The nouthern hemisphere data are based on photographic data of the National Geographic Society Palomar Observatory Sky Survey (NGS-POSS) obtained using the Oschin Telescope on Palomar Mountain. The NGS-POSS was funded by a grant from the National Geographic Society to the California Institute of Technology.
The plates were processed into the present compressed digital form with
The Digitized Sky Survey was produced at the Space Telescope Science Institute under US Government grant NAG W-2166. Investigators using these scans are requested to include the above acknowledgements in any publications.