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AAVSO Special Notice #68

PROBABLE SUPERNOVA IN NGC 5530
September 13, 2007

The Central Bureau for Astronomical Telegrams announced in CBET 1065 (Daniel W. E. Green, ed.) the visual discovery by Robert Evans, Hazelbrook, NSW, Australia, of a ~13.5-magnitude bright probable supernova on Sept. 13.44 UT in NGC 5530 (Lupus). To quote from CBET 1065, the object is "located about 24" west and 25" north of the nucleus of the galaxy NGC 5530 (R.A. = 14h18m.5, Decl. = -43o24', equinox 2000.0) -- not to be confused with a bright foreground star on the northeast edge of the nucleus. Nothing is visible at this location on the ESO "B" survey or in the photograph of this galaxy in Vickers and Wassilief's *Deep Space CCD Atlas: South*, although a very faint knot appears in the position of the star in the blue survey. The existence of the new star was confirmed visually within a few minutes by D. Nitschki, using the same telescope, and within 20 minutes by S. Quirk using his 0.31-m reflector (+ Gstar-ex CCD, 2-min unfiltered exposure); a measurement of the variable via Astrometrica software yields red mag 14.3 and R.A. = 14h18m25s.6, Decl. = -43o22'54"."

More information will be forthcoming as it becomes available. For now, please report observations to the AAVSO as 1412-42 SN NGC5530 and be sure to indicate what stars were used as comparisons. The field may be plotted by entering the coordinates into VSP: http://www.aavso.org/observing/charts/vsp/ [4] . Put a checkmark in the box labeled "Use DSS Image" to see the field including the galaxy itself.

Congratulations to Bob on his latest VISUAL discovery!

This AAVSO Special Notice was compiled by: Elizabeth O. Waagen

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