Central Bureau for Astronomical Telegrams
IAUC 5482: 1991h1; SW UMa; N Cyg 1992
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Circular No. 5482
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
COMET MUELLER (1991h1)
R. D. Gehrz, University of Minnesota, reports that infrared
observations by T. J. Jones, G. Lawrence, E. Ney and himself on
Mar. 24.8 UT failed to record this comet. Spiral scans, using
beam diameters of 15" at Mt. Lemmon (AZ) and 20" at the O'Brien
Observatory (MN), at rates of 1 beam diameter per second and with
a mesh of 1 beam diameter, were made out to a distance of 5' from
the comet's predicted position. Upper limits (3 sigma,
integration time 1 second) on the detection were L = +1.5, M =
0.0, N = -2.5. From a comparison with other comets for which
there have been infrared detections, it appears that comet 1991h1
must currently be at least 2 mag fainter than predicted on IAUC 5464.
SW URSAE MAJORIS
Recent visual magnitude estimates, in part submitted by the
AAVSO, indicate that this object (cf. IAUC 5199, 5206) is in outburst:
Mar. 18.94 UT, [12.5 (P. Schmeer, Bischmisheim, Germany); 19.86, 11.4 (H.
Dahle, Oslo, Norway); 19.88, 11.4 (O. Midtskogen, Tranby, Norway); 21.15,
10.5 (R. Stewart, W. Paterson, NJ); 21.79, 11.0 (Schmeer); 22.06, 11.4 (P.
Dombrowski, Glastonbury, CT); 22.08, 10.6 (G. Dyck, Assonet, MA); 22.14,
10.6 (J. Griese, Rock Hill, CT); 22.18, 10.9 (P. Abbott, Leduc, Alberta,
Canada); 23.86, 11.2 (Schmeer); 24.09, 11.5 (P. Sventek, Houston, TX).
NOVA CYGNI 1992
A. Piersimoni and A. Di Paolantonio, Collurania Observatory,
Teramo, provide the following photometry, obtained using a 0.50-m
reflector with a photon-counting system: Feb. 26.65 UT, V = 4.84 +/-
0.01, B-V = +0.37 +/- 0.02, U-B = -0.71 +/- 0.02; 29.64, 5.46 +/- 0.02,
+0.27 +/- 0.01, -0.83 +/- 0.02; Mar. 4.63, 5.92 +/- 0.02, +0.27 +/- 0.02,
-0.82 +/- 0.02; 19.61, 6.92 +/- 0.03, +0.10 +/- 0.01, -0.81 +/- 0.02.
Further visual magnitude estimates: Mar. 23.12 UT, 6.8 (A. Pereira,
Cabo da Roca, Portugal); 23.46, 6.9 (W. Dillon, Missouri City, TX);
24.34, 7.0 (J. McKenna, Upper Montclair, NJ).
Corrigenda. On IAUC 5479, the spectroscopic observations
reported by M. Kidger for Mar. 4 should have been given as Mar. 5, and
the resolution was 20 nm, not 55 nm.
1992 March 25 (5482) Brian G. Marsden
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