Central Bureau for Astronomical Telegrams
IAUC 2989: HD 5980; V1500 Cyg; GU Sgr
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Read IAUC 2990
Circular No. 2989
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK
Western Union: RAPID SATELLITE CAMBMASS
HD 5980
T. Schmidt-Kaler, Ruhr Astronomical Institute, Bochum University,
reports: "R. Rudolph communicates that the object HD 5980 =
R14, described by Feast et al. (1960, Monthly Notices Roy. Astron.
Soc. 121, 337) as a Wp star of V = 11.6 and considered by us as the
nucleus of the SMC, now has V = 15.0 and appears double with a
nebulous wisp."
V1500 CYGNI
G. J. Ferland, J. Tomkin and J. H. Woodman, Department of Astronomy,
University of Texas at Austin, write: "Low-noise, 0.8-A-resolution,
time-resolved (10 moin) observations of [O III] 4959 A
and 5007 A in V1500 Cyg were obtained during Aug. 21-23 with a Reticon
at the coude focus of the McDonald Observatory's 270-cm telescope.
A 90-min set of observations shows no profile variations
greater than 5 percent. Subsequent H-beta wide-filter observations
(whose flux is dominated by [O III] with H-beta making a moderate
contribution) show the intensity of the emission line to be constant
to 2 percent. Photometric observations with a y filter (which our
spectroscopic observation shows to be clear of emission lines) on
the 76-cm telescope reveal variations of 0.4 magnitude, indicating
that the continuum is the source of the photometric activity
reported by other observers. Future photometry should strive to
avoid the constant emission lines (the strongest being [O III]
4959 A and 5007 A and [N II] 6548 A and 6584 A) and concentrate on the
continuum. The U filter is fairly clear of strong emission (O III,
[Ne III] and [Ne V] contributing weakly). Another excellent bandpass
would be a blue-sensitive photocathode (1P21 or bialkaline)
combined with a blue-cutoff (cutoff past 5100 A) filter."
Selected recent visual magnitude estimates: July 20.88 UT,
11.9 (R. Lukas, Wilhelm Foerster Observatory); 28.89, 12.0 (Lukas);
Aug. 4.19, 11.6 (S. O'Meara, Harvard College Observatory); 11.23,
11.7 (O'Meara); 19.82, 12.2 (Lukas); 26.21, 11.7 (O'Meara).
GU SAGITTARII
J. Bortle, Brooks Observatory, provides the following visual
magnitude estimates of this R CrB-type variable (cf. IAUC 2980):
Aug. 3.1 UT, 12.0; 18.1, 12.0; 25.1, 11.6; 31.1, 11.4.
1976 September 23 (2989) Brian G. Marsden
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