Central Bureau for Astronomical Telegrams
IAUC 6736: Notice
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Circular No. 6736
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)
NOTICE TO CONTRIBUTORS
Over the course of twelve hours on Sept. 6 UT the Central Bureau
received two reports---purportedly independent---of the CCD discovery of an
alleged supernova in NGC 772. Each indicated that the object was
of mag 15-16, but the first was offset some 2' northeast
and the second some 2' northwest of the center of the galaxy;
the first observer did not record the observation time, but this image was
evidently obtained some 26 hr before the second observer's image was
obtained. Each observer noted that the alleged supernova was not present
on images from earlier nights and that it did not move over the course of
an hour or two; furthermore, the first observer remarked that two different
checks for known minor planets in the vicinity did not reveal a match.
The second observer indicated that this report had also been sent to
selected other observers, with a note that "spectroscopic
confirmation was requested". On receipt of the information from the first
observer, a check at the Central Bureau immediately revealed that,
although the observation time had not been specified, the alleged
supernova northeast of the galaxy was probably minor planet (5240), then
very close to its morning stationary point and in fact still moving very
slowly eastward. This information was relayed to the observer.
Nevertheless, within six hours of this (i.e., still two hours before
the second observer's image was obtained), a copy of the first observer's
image was present in the World Wide Web, together with the mention
(though without details) of an apparent confirmation by the webmaster.
Measurement of the WWW image at the Central Bureau clearly confirmed
the indicated identity of the "supernova" with (5240) and allowed the
observation time to be specified. In the Bureau's message to the first
observer, it was also mentioned that minor planet (1887), comparable to
(5240) in brightness, was near the galaxy. Examination of the WWW image
showed that (1887) would have been just off the southern edge at the time
of observation. Nevertheless, (1887) was moving northward at five times
the rate of (5240), and it had already begun its westward motion. On
receipt of the second report of an alleged supernova, with the
indication that it was 125" west and 75" north of the center of
the galaxy, it was then immediately clear that this observation in fact
referred to (1887).
The above account is given in some detail because it allows several
points to be made. These will be discussed on IAUC 6737, together
with a proposed remedy for the problem.
(C) Copyright 1997 CBAT
1997 September 6 (6736) Brian G. Marsden
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