Annual Report to Council (2004)

Deep-Sky Observing Section annual report

The year under review has seen a marked increase in activity in the work of the Section.

Magda Streicher of Pietersburg has continued to document southern sky splendours, sketching upwards of 120 objects. She re-visited the Bennett catalogue, observed the 23 obscure Hogg open clusters, and initiated her own project on star chains.

The Bloemfontein Centre Deepsky Group, under the capable leadership of Gerrit Penning, has established their own observation program for the year, consisting of 20 deep sky logs. The logs are considered a great method for recording observation history and to serve as a future reference point. In addition, the logs also contain other observation exercises (e.g. navigational) and contain guidance for the observation of satellites, planets etc. On 28 February 2004, observations officially started as members were introduced to the activity plan for the year. The deep sky group consists of about 12 highly motivated members. Observation evenings are organized twice a month as the moon and clouds allow. It usually takes place from members’ homes in the city. One reason why the Centre considers its deep sky group to be effective is the use of binoculars during such evenings and the fact that ordinary backyard astronomy is done. A dedicated deep sky webpage was also constructed for the Deep Sky group.

The Director has continued work on open cluster remnants, and is well-along with the development of software to extract data from various catalogs (currently, the UCAC2 and 2MASS catalogues) in order to analyse cluster stars in terms of proper motion, photometric membership, etc. The software is able to generate and partially interpret colour-magnitude and two-colour diagrams using isochrones, radial density profiles and vector point diagrams. It is intended that these routines will eventually be used to automatically search for clusters in large stellar databases. Analysis of various star-groupings is underway, including those groupings listed by Loden, Isserstedt and Uranova, as well as those presented by the director at the previous ASSA Symposium.

Auke Slotegraaf