Re: [comets-ml] comet C/2012 S1 ISON today
- An interesting (and continuing) aspect of c2012 S1 is that it is not changing much at
all, morphologically speaking.
At close to the same time this image was taken we measured (12 measurements, April 29
and April 30 UT) the comet (Arkansas Sky Observatories, H45), using diaphragm
adjusted aperture via CCD and UCAC-4 star calibration, at still only 15.9-16.0 (m1);
the measurements were slightly variable since the comet is now so low in the NW skies
and subject to refractive interference from moment to moment.
Thus, in terms of brightness, the comet reached a plateau back in early March of 15.8
to 16.0 and pretty much remains there. Likewise the overall diameter and tail extent
remains unchanged as well.
The coma overall is still measured at a fairly consistent 10-11" arc with about an
18" length tail, these measurements virtually unchanged and non-increasing during the
past five weeks or more. A more pronounced stellar condensation is now seen within
the small coma, but other than that the tail, coma and brightness characteristics
remain unchanged in a very long period of time.
Based on current elements, the comet should have a total brightness of about 14.9;
This lack of physical development can be only partially attributable to orbital angle
and phase considerations.....the comet is simply not developing as hoped at this
Dr. P. Clay Sherrod
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
----- Original Message -----
From: "ligustri rolando" <rolando.ligustri@...>
To: "cometas" <Observadores_cometas@yahoogroups.com>; "comet images"
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Sent: Tuesday, April 30, 2013 1:34 PM
Subject: [comets-ml] comet C/2012 S1 ISON today
> Rolando Ligustri
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