AAVSO: Possible Nova in Sgr

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Description of the Nova Sgr 2002 no.2 Spectrum

The spectrum of Nova Sgr 2002 No. 2 was taken on 09/17/2002 2:42 UT by Doug West in Mulvane, Kansas. The spectrum was produced by an non-objective slitless spectrometer. The spectrometer consists of a Rainbow Optics diffraction grating, a 0.2 m SCT, and a SBIG ST-9E CCD camera. The data reduction is accomplished using MIRA and custom software. The spectrum is flux calibrated relative to Vega. The "+C" term in the flux is due to the lack of correction for airmass. The slope of the line is correct but the flux value will have a constant offset. The exposure time was 30 seconds.

The spectrum shows a emission peak at the Hydrogen Alpha line (6562.8 Angstrom). This is typical for a nova a few days after the maximum. The Hydrogen Beta line (4861.3 Angstrom) is also in emission with much lower intensity than the Hydrogen Alpha. The peak at approximately 5100 Angstrom is due to contamination from a background star. The slope of the spectrum is consistent with a reddened object.

Alert Notice 296 Text

            THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
                  25 Birch Street, Cambridge, MA 02138 USA
                         INTERNET:  aavso@aavso.org
                  Tel. 617-354-0484       Fax 617-354-0665

                AAVSO ALERT NOTICE 296 (September 16, 2002)


Please note that we have modified the layout of the Alert Notice. We hope
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SUBJECT: 1756-25 NOVA SAGITTARII 2002 NO. 2 - POSSIBLE NOVA IN SAGITTARIUS

1756-25 NOVA SAGITTARII 2002 NO. 2

Event: Possible nova

Discovered By: William Liller, Vina del Mar, Chile

Discovery Magnitude: 8.5: photovisual (80-mm f/1.4 camera lens, orange
filter, and Kodak TP film; magnitude uncertain due to nearby moon)

Discovery Date: The 8.5: object appears on photographs taken on Sept
15.1102, 15.1227, and 15.1241 UT

R.A. (2000): 18h 02m 22s.07 +/- 0s.15
Decl. (2000): -25o 20' 30".4 +/- 1".5  (IAUC No. 7971)

AAVSO Chart(s): 'c' scale chart available at
http://www.aavso.org/charts/catalog/SGR/V4742_SGR/

Report Object to the AAVSO as: 1756-25 N SGR 02#2

Observations Reported to the AAVSO: September 16.007 UT, 8.13 CCDV, W.
Liller, Vina del Mar, Chile; 16.082, 8.0, R. King, Duluth, MN; 16.177, 8.1,
C. Puig, Santa Clara, CA (via IAUC No. 7971); 16.3035, 8.0, J. Bedient,
Honolulu, HI; 16.391, 7.9, M. Linnolt, Honolulu, HI

Spectra: Spectra taken by Liller reveal emission lines (he is still working
on the reduction)

Notes: For more information, see the announcement in International
Astronomical Union Circular (IAUC) No. 7971


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submission tool WebObs), or by email in AAVSO format to
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Many thanks for your valuable astronomical contributions and your efforts.

Good observing!

Kerriann H. Malatesta
Technical Assistant

On behalf of
Janet A. Mattei
Director

V4742 Sgr - Possible Nova in Sgr