(66146) 1998 TU3

This small solar system body belongs to the Earth-crossing Aten group of asteroids, which hence have some survival interest. In 2003 October it was well placed for observation, at around mag. 12-13, after a close opposition. A team of Australian amateur astronomers was formed to study it: Colin Bembrick, (Bathurst, NSW), Greg Bolt (Perth, WA), David Higgins (Canberra, ACT), and myself in Melbourne. Altogether we obtained eleven sets of time-series observations over ten nights in a two-week period. The full report of this study (Richards et al) appears in the Minor Planet Bulletin, 34:3 (2007 Jul-Sep). In summary, we found a period of 2.3779 ± 0.0004 h and an amplitude of 0.1 mag. Below are plots of the best sets of my data. More information, and tables of the photometric data are available on enquiry by email.
Instrumentation used at Woodridge Observatory was a 180 mm Astro-Physics refractor and an SBIG ST-7e CCD camera; integration times 30 s unfiltered. Photometry was by MaxIm and data analysis and plotting by Peranso.

Data plot of 2003-10-06. Woodridge Observatory. Late scatter is due to the low altitude of the target.The plot is bimodal (two peaks per rotation, as is normal.) Note the second higher peaks appear to have a small peak on the declining shoulder.