Wavelength 21 cm
Data sources Parkes Observatory
Data products HICAT, NHICAT

The HI Parkes All Sky Survey (HIPASS) was an astronomical survey for neutral atomic hydrogen (HI). Data was taken between 1997 and 2002 using the Parkes Observatory.[1] HIPASS covered 71% of the sky and identified 5317 sources emitting HI's signature wavelength.[2] Discoveries include the Leading Arm of the Magellanic Stream and gas clouds devoid of stars.


HIPASS observations had a redshift range of -1,280 to 12,700 km s-1.[3] HIPASS was the first blind HI survey to cover the entire southern sky.[4]

Southern Sky observations

Observations of the southern sky started in February 1997, and were completed in March 2000, consisting of 23020 eight-degree scans of each of 9 minutes duration.[3] HICAT, the catalogue of HIPASS, contains 4315 HI sources.[2][4] HIPASS scanned the entire southern sky five times.[5]

Northern Sky observations

Northern HIPASS extended the survey into the northern sky. The entire Virgo Cluster region was observed in Northern HIPASS.[2] NHICAT, the catalogue of the northern extension of HIPASS contains 1002 HI sources.[2]

Multibeam Receiver

Observations for HIPASS were taken using the Parkes 21 cm Multibeam Receiver.[6] The instrument consists of a Focal Plane Array of 13 individual receivers arranged in a hexagonal pattern.[6] Built in a collaboration between numerous institutions, it was funded by the Australian Research Council (ARC) and the Australia Telescope National Facility (ATNF) to undertake the HIPASS and ZOA surveys.[6]


Leading arm of Magellanic Stream

HIPASS discovered the Leading Arm of the Magellanic Stream.[5] This is an extension of the Magellanic Stream beyond the Magellanic clouds.[5] The existence of the Leading Arm is predicted by models of a tidal interaction between the Magellanic Clouds and the Milky Way.[5]

HIPASS J0731-69

HIPASS J0731-69 is a cloud of gas devoid of any stars.[7] It is associated with the asymmetric spiral galaxy NGC 2442.[7] It is likely that HIPASS J0731-69 was torn loose from NGC 2442 by a companion.[7]

HIPASS J1712-64

HIPASS J1712-64 is an isolated extragalactic cloud of neutral hydrogen with no associated stars.[8] The cloud is a binary system and is not dense enough to form stars.[8] HIPASS J1712-64 was probably ejected during an interaction between the Magellanic clouds and the Milky way.[8]

New galaxies in the Centaurus A/M83 Group

Ten new galaxies were identified in the Centaurus A/M83 Group, bringing the total (at the time) to 31 galaxies.[9]

See also