2016 schedule


History and Observations of the Jewel Box: 1603 to 1983

Andrew James

Non-Affiliated Independent Amateur Astronomers (NAIAA)

One of the brightest and most interesting historical open star clusters in the southern skies is the small open star cluster coined as the Jewel Box or NGC 4755. This brilliant cluster was first appeared as a hazy star in Bayer’s ‘Uranometria’ in 1603, but its nature as an open star cluster was not established until Abbe Lacaillé in 1752.

In 1824-26, James Dunlop made one of the first detailed drawing, as did Sir John Herschel in 1834, and again, by H.C Russell in 1880. Tasmanian amateur Francis Abbott, in 1862, published his paper on this cluster, dramatically claiming, by his carefully comparison of Herschel’s and Dunlop’s drawings, presumably showing that many of the stars had changed in relative position by proper motion, and even suggested the number of stars or their colours differed. Open questions on this problem remained, solved after comparing several Sydney Observatory astrographic images obtained at throughout the 20th Century.

This poster paper shows much of the available early historical observations on the Jewel Box in Eastern Australia, and examines the reasoning and observations leading to Abbott’s proposition. Also discussed is what this controversy did to the reputation of Australian astronomy, and learn of this influence on studies into open clusters and stellar evolution. (This presentation is aligned with the planned visit to Sydney Observatory during NACAA 2016, which inspects the new East Dome and the recent public display of the old Melbourne astrograph.)