All STScI domains will be unavailable Saturday, 30 January, 2021, 7:30 AM EST - 4:00 PM EST (12:30 - 21:00 UTC) for network maintenance.
Holwerda et al. examined 32 HST/WFPC2 archival fields of 29 spiral galaxies (Sab and later) for their paper The Opacity of Spiral Galaxy Disks. IV. Radial Extinction Profiles from Counts of Distant Galaxies Seen through Foreground Disks (2005, AJ,129:1396-1411).
The majority of the data are from the Cepheid distance scale Key Project.
The explicit goal was to provide deep mosaics in both V- and I-band with a
better sampling in order to identify background galaxies through the foreground disk.
For more information about these data please see the readme file.