P/2012 T1 (PANSTARRS) was discovered by the PAN-STARRS survey on 2012, Oct. 06.53 with a 1.8-m reflector + CCD located at Haleakala, HI, USA.
Richard Wainscoat, Henry Hsieh and Larry Denneau described the object to have a PSF larger than stars nearby (1.5″ vs 1.07″). The object was posted on the NEO Confirmation Page under the temprary designation P104kFN.
Apart from their internal confirmation team from Hawaii (Dave Tholen, Marco Micheli and Garrett T. Elliott using the UoH 2.24-m reflector), observatories from the “T3 project” were the only ones to confirm it as a comet.
The first who reported to us cometary activity was Hidetaka Sato, using a 0.43-m remotely from New Mexico on Oct. 10.3, noted that “P104kFN is a potential comet with a round coma of 10″ in diameter. A tail was 12″ toward PA 250 degree.”
After his observation I managed to observe it under a clear sky the following night (the first after three weeks of bad weather in northern Italy!), confirming its clear cometary appearance: in a stack of 56 minutes of total exposure time in good conditions, it has a diffuse aspect, with a coma 10″ wide elongated in PA 253° for at least 15″.
Also H21-ARI confirmed it with a 0.61-m f/4 astrograph from Westfield, IL, USA, on Oct. 11.29: round 12″ coma and a tail 15″ long toward PA 240 degrees.
Also Lulin Observatory from Taiwan confirmed it with the LOT 1.0-m f/8 telescope, but for some reasons they were not included in the circular.
Results were published in CBET 3252 (subscription required) and astrometry, together with elliptical orbital elements, in MPEC 2012-T55. Gareth Williams found prediscovery observations from PAN-STARRS back to 2011, Jul. 28, so the orbit is already pretty solid.
With a semimajor axis of 3.05 AU, low eccentricity and inclination and a Tj parameter of 3.18, P/2012 T1 belongs to the Main-Belt Comets group.
In all the images, visible below, it’s clear the faint and diffuse tail.
H06 (H. Sato) image: