Friday, 7 September 2007

2007 August notes: 2007 QA1

August saw a rash of new main belt objects picked up from Great Shefford and as I write this four have very good, secure orbits, three others are OK with several weeks of observations and one I only managed to record on two nights and so is effectively lost.

2007 QA1 was another new object I picked up on the night of Aug 16 at mag +19.0 which turned out to be interesting - it was heading almost due south (in p.a. 195 deg) though was not moving unusually fast. I could not identify it with any known object on the MPCs Minor Planet Checker web page. I also checked it against the MPCs NEO rating page to see if it had any chance of being a NEO and that came back with a very low rating of 3% (50%+ is required to get an object placed on the NEO Confirmation Page). I held onto the positions to try and get a second night but the next night was cloudy.

Later that day the MPC added it to the NEOCP, having received positions from the Lowell Observatory. Although it did not end up being a NEO (perihelion distance was just greater than the 1.3 AU limit) it was a Mars crosser and having appeared on the NEOCP from Lowell it was effectively lost to me as a discovery - the first observatory reporting even a single night of observations will be granted discovery credit if it appears on the NEOCP, unlike normal Main Belt objects where it is generally the first observatory to report two nights of positions that gets discovery credit.

Lesson learned: Don't rely on the NEO rating page to decide if an object is interesting! In fact it's motion was very unusual, of the 1794 minor planets that were mag +23 or brighter within 5 degrees of 2007 QA1, only one other was moving in a direction with a p.a. less than 209 degrees. Next time(and I hope there is one!) if another potentially interesting object turns up I will submit a single night of positions to the MPC and let them decide whether it is interesting enough to put on the NEOCP...