Special Notice #138: Probable Nova in Sagittarius [V5580 Sgr, Nova Sgr 2008 No. 2]

AAVSO Special Notice #138

Probable Nova in Sagittarius
December 2, 2008

As announced in CBET 1591 (D.W.E. Green, editor), W. Liller of Vina del Mar, Chile announced the discovery of a probable nova in Sagittarius [V5580 Sgr, Nova Sgr 2008 No. 2] on 2008 November 29.040 (JD 2454799.540); the object was at an approximate magnitude of 8.0 on photographs taken with Tech Pan film with an orange filter.  A subsequent photograph taken on 2008 November 29.999 (JD 2454800.499) showed the object at a magnitude of 7.8 (orange filter).  The object was detected at magnitude 10.3 on 2008 November 23.037 (JD 2454793.537), but was fainter than magnitude 11.0 on 2008 November 20.035 (JD 2454790.535).  Subsequent objective grating spectrographs also by W. Liller indicate strong H-alpha emission with FWHM of approximately 2500 km/s, meaning this object is almost certainly a nova.  As reported in vsnet-alert 10774, the object was also detected by H. Maehara on 2008 Dec 2.36 (JD 2454802.86) at an approximate V magnitude of 8.76.

The photographic astrometry provided by Liller is accurate to approximately 1 arcminute, and the nova has not yet been precisely identified within the field.  Both photometry and astrometry are urgently requested at this time.  This object is very close to the horizon at sunset, and will soon be lost for the season.  Observations within the next few days are critical.  

Approximate (J2000) coordinates for this nova are:

RA: 18 22 00 , Dec: -28 03 00  (1+ arcmin)

Finder charts for this field may be plotted by entering the coordinates above into VSP: http://www.aavso.org/observing/charts/vsp/

Please report all observations to the AAVSO using the name "N SGR 08#2"; the AUID for this object is "000-BJJ-234". 

An AAVSO Alert Notice will be issued [no Alert Notice was issued] if and when precise astrometry is available, and the object will be added to VSX at that time.

This AAVSO Special Notice was prepared by Matthew Templeton.

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