The 3rd Ariel-V SSI Catalog contains a list of X-ray sources detected by the University of Leicester's Sky Survey Instrument (SSI) on the Ariel-V satellite, and published (in 2 papers) as the Ariel-V (3A) Catalog: Warwick et al. 1981, MNRAS, 197, 865 (the low galactic latitude sources) and McHardy et al. 1981, MNRAS, 197, 893 (the high galactic latitude sources). The catalog is based on observations extending over a 5.5 year period from 1974 October until 1980 March. The SSI had a field of view of 0.75 by 10.6 degrees (FWHM) and had an energy range from 2 to 18 keV. A detailed description of the SSI is given by Villa et al. 1976, MNRAS, 176, 609. For a more detailed discussion of how the 3A Catalog was created, please refer to the Warwick et al. (1981) and McHardy et al. (1981) papers. This online catalog was created by the HEASARC in March 2003 based on the merger of two original tables originally obtained from the ADC website (<a href="https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/ariel3a/hilat.dat">https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/ariel3a/hilat.dat</a>; and <a href="https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/ariel3a/lowlat.dat">https://heasarc.gsfc.nasa.gov/FTP/heasarc/dbase/misc_files/ariel3a/lowlat.dat</a>;). This is a service provided by NASA HEASARC .