2016 schedule

Sat 11:00-11:30
Theatre 106

The Parramatta Star Catalogue: A New Perspective

Andrew James

Non-Affiliated Independent Amateur Astronomers (NAIAA)

The Parramatta Star Catalogue (PSC), made during the 1820s, was the first serious attempt to produce a useable and accurate catalogue of southern stars down to eighth magnitude. It was originally instigated by Sir Thomas Brisbane as a private concern, involving the creation of Parramatta Observatory in Australia, furnishing its astronomical equipment, and hiring the observers, Charles Rümker and James Dunlop. Completed on 2nd March 1822, they began setting up the 5 1/2-foot Troughton Transit Telescope and 2-foot Mural Circle.

Nearly continuous astrometric observations were made from 2nd May 1822 to 1824, becoming more sporadic until they ended on 2nd March 1826. Although the final catalogue is in Brisbane’s name, most of these measures were made by James Dunlop. They were later officially reduced at Royal Observatory, Greenwich, by William Richardson, from the recorded manuscript, then finally published in 1835. At first, the 7385 catalogued stars were heralded as a most significant achievement, but careful examination of the results showed many flaws or significant and inexplicable errors. These were mostly attributed to equipment damage, though others consider that the instrumentation was adjusted too much and that these changes were not properly recorded, or that the observers were not diligent enough and lacked support.

Perhaps the greatest problem of this whole work was the inexcusable large number of missing stars that exist well above the stated catalogue magnitude limit. The presenter has recently created and released a new digital version of this catalogue, that is usefully cross referenced to modern sources. This will be the author's first presentation regarding some new insights in its astrometric weaknesses, development and overall completeness. (During the NACAA, the author hopes to discuss the upcoming bicentennial of the creation of Parramatta Observatory, and the possibility of an organised special astronomical conference to celebrate the event in 2021 or 2022.)