A discovery by Brian Skiff at the Lowell
Observatory, on images taken starting at 08:08UT on 16 May 2005 was recognised as a comet
by him and reported to the Minor Planet Center. It was drifting
slowly west at a high northern declination in Draco and well placed
in the northern hemisphere soon after evening twilight.
It appeared on the NEO Confirmation Page 15 hours later at
23:08UT on 16 May and was picked up and reported to the MPC from the
Powell
Observatory in Kansas just after 06:00UT on 17 May. The NEO
Confirmation page was updated at 13:27UT on 17 May with the
adjustments to the ephemeris prediction that the Powell observations
provided.
At Great Shefford skies were good during the day on the 17th but towards
evening cloud started to increase. By the time it was dark the object was still on the NEO
Confirmation page and was already at an altitude of 54º but the Sun
was just 13º below the horizon. 24 images were obtained starting 21:43UT
and as the first handful of images were downloaded they were stacked
to make sure the object was visible. It was immediately obvious with
just 5 images combined that it was a comet, with very noticable coma
and indications of a tail. An hour later the skies had clouded
up and no further work could be done.
Brian Skiff reported the object as having a 16" diameter
moderately condensed coma, with a narrow fan-shaped tail about
90" long tail in p.a. 325º. At Powell, Richard Trentman
described a coma extended by 1.3' (~80") in p.a. 305º and from
the images taken at Great Shefford the comet was described as having
a moderately condensed 12" diameter coma and a 20" long
broad tail in p.a. 320º, possibly extending to 50".
The initial orbit calculated by Brian Marsden at the Minor Planet
Center published on MPEC
2005-K15 at 22:49UT on 17 May shows the comet to be distant,
about 4.3 AU from Earth and 4.5 AU from Sun at discovery, in an
orbit highly inclined to the ecliptic (i = 80º) with a perihelion
distance of 4.2 AU expected to be reached in November 2005.
However, with observations spanning less than 38 hours and
movement on the sky of less than ¼º the orbit is flagged as being
'very uncertain' and it is to be expected that substantial revisions
will be made in the days and weeks to follow as further observations
are reported.
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