13p 20230824 ahale

The recovery of Comet 13P/Olbers (short version):

I first began searching for Comet 13P in October 2022, utilizing the telescopes of the Las Cumbres Observatory (LCO) global network, where I’m a member of the Global Sky Partners. My attempts were all unsuccessful up through the time the comet entered conjunction with the sun earlier this year, then beginning in mid-June 2023 following its emergence into the morning sky I have been making additional attempts on roughly a biweekly basis.

On August 24.7 UT I took two 10-minute exposures with one of the 1.0-meter telescopes at LCO-Siding Spring. When examining these images I spotted a faint moving object a little over 5 arcminutes from the MPC’s ephemeris prediction, along the line of variation at roughly Delta_T ~ -0.73 day from that prediction. Armed with this information, I successfully detected images of the comet on exposures taken on August 13.1 UT from LCO-SAAO; these images are very weak, and I’m not surprised I failed to notice them at the time. Since then I have obtained follow-up images of the comet on several occasions using LCO telescopes at both facilities, the more recent ones being based on a post-recovery orbit privately communicated by Syuichi Nakano that utilized my recovery positions.

I’m attaching the recovery image(s) from August 24. This is a stack of the two exposures (combined exposure time 20 minutes); approximate field dimensions 3.5 x 3.5 arcminutes, standard orientation (north up, east left). The comet’s appearance in all images has been basically stellar, and its brightness is between 21st and 22nd magnitude.

Based upon its behavior during previous returns, Comet Olbers should reach a peak brightness near 7th magnitude when near perihelion next June.