Release History for the AAO/UKST H-alpha survey of Southern Galactic Plane

• May 12th 2020 - a total of two scan lanes of data, one in Halpha field HAL0972 and one in short red field HAR0879 were found to be corrupt. These lanes have been replaced with blank values, 1 lane is about 4 % of a field.
• September 22nd 2003: penultimate release of the survey is now online. All astrometry has been rereduced using UCAC2 for the individual film distortion maps (but still using the Tycho-2 reference catalogue). Both the H-alpha and red scans in fields 0173 and 0273 have been replaced. All photometric zeropoints have been rederived to incorporate new field data; pre-existing photometry will have changed at the few percent level while fields adjacent to new fields may have changed at the 10 percent level. The Galactic plane survey is now complete with the exception of the red exposure in field 0598.
• January 23rd 2003: new release of the survey is now online. 202 Galactic plane fields are now present in Halpha and matching short red; furthermore the SSS I band data are now paired in and appear in the object catalogues derived using the interface. New default photometry is supplied at access time: the Halpha and I colours are corrected for systematic errors using the same procedure as for the SSS; in the object catalogue form there is a new option to switch this feature off if the old uncorrected photometry is required.
• August 23rd 2002: small bug fixed in object catalogue access codes (this bug sometimes resulted in missing data when catalogue queries traversed field boundaries).
• March 2002: First release of new SHS interface via direct modification of the SSS interface