2010G2/＜ Hill 彗星＞

＊　ヒル彗星がよいの北東の空に！　＊ Discovery COMET C/2010 G2 (HILL) R. E. Hill reports his discovery of a comet on Catalina Sky Survey CCD images taken with the 0.68-m Schmidt telescope (discovery observation tabulated below); four co-added 40-s exposures taken in 2"-3" seeing during Apr. 10.45-10.47 UT show a diffuse coma about 6"-8" across with a broad, diffuse tail about 8"-10" long in p.a. 200 deg. Four co-added 60-s follow-up images by R. A. Kowalski and G. M. Hupe with the Mt. Lemmon 1.5-m reflector on Apr. 10.5 also show the faint, broad, straight tail in p.a. about 200 deg; additional images with the same telescope by S. M. Larson on Apr. 11.44-11.46 show a 20" tail in p.a. 200 deg. After posting on the Minor Planet Center's 'NEOCP' webpage, other cometary astrometrists have also commented on this object's cometary appearance during Apr. 11.2-11.7. A. Novichonok and D. Chestnov (remotely with a 36-cm Maksutov-Newtonian telescope at Tzec Maun Observatory near Cloudcroft, NM, U.S.A.) found an obvious faint coma with diameter 0'.2 and no tail. W. H. Ryan and E. V. Ryan (Magdalena Ridge Observatory, 2.4-m reflector) find a coma and a faint tail in p.a. about 200 deg on R-band images. E. Guido and G. Sostero (remotely using a 0.25-m reflector at the RAS Observatory, Mayhill, NM) report that eighteen co-added 120-s unfiltered exposures reveal a diffuse coma nearly 10" in diameter; H. Sato, Ota-ku, Tokyo, Japan (also remotely using a 0.25-m reflector at the same site) measures a 15" coma. R. Ligustri, Udine, Italy (remotely using a 0.40-m reflector at the RAS Observatory, Moorook, Australia) writes that eleven 180-s co-added images show a faint 20" tail in p.a. 235 deg.

from　IAU Central Bureau for Astronomical Telegrams
http://www.cbat.eps.harvard.edu/iauc/09100/09134.html