THE ASTRONOMER Electronic Circular No 397 1990 Mar 27 18.27UT
Microlink:MAG60138 JANET:GMH at UK.AC.RO-GREENWICH.STARLINK
Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke,
Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074
Telex: 94082518 Answerback: TAGUY
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DWARF NOVAE ALERT
Professional astronomers at Oxford University have approached us
asking if we will participate in a joint venture next week
whilst they monitor dwarf novae with the IUE. They wish to receive
early warning of ANY dwarf nova which starts to rise towards
maximum so that they can plan observations. The top priority
night is April 3/4 but I would suggest we mount an intensive
observing campaign from April 2-6.
On each evening please start observing as early as possible and
report your estimates of ALL dwarf novae, regardless of outburst
phase, by 10pm BST (21.00UT) at the latest to the Editor. Any
estimates after this deadline should be reported early the
following evening. No calls are needed after 10pm as this is
the deadline for collation and re-routing to Oxford for IUE
scheduling.
Transmission of results can be by telex, e-mail (to RGVAD unless
down) or, failing this, by telephone.
We need extensive help by overseas observers to help beat
weather difficulties, and those on e-mail can perhaps enlist
a group of observers in their country to help.
Please let me know as soon as possible if you intend to
participate.
SUPERNOVA 1990G IN IC 2735
Jean Mueller reports her discovery of a supernova in IC 2735
(UGC 6364; R.A. = 11h18m22s.2, Decl. = +34 37'04", equinox 1950.0);
the object, at mpg about 15 and located 34".6 west and 13".3 north
of the galaxy's centre, was found on a plate taken Mar. 19 UT in
the course of the second Palomar Sky Survey with the 1.2-m Oschin
Schmidt Telescope. R. Kirshner and B. Leibundgut, Center for
Astrophysics, report the independent discovery of this object by
Ann I. Zabludoff, CfA, using the TV guider of the 1.5-m Tillinghast
reflector at Mount Hopkins on Mar. 20; the supernova's position is
R.A. = 11h18m19s.4, Decl. = +34 37'18" (equinox 1950.0; 34" west,
14" north of the galaxy's nucleus). R. Schild, CfA, estimated mag
R about 16.3 on the same night with the 0.61-m telescope (+ CCD);
C. Smith, CfA, obtained a spectrum with the Multiple Mirror
Telescope, indicating a type-Ia supernova about 1-2 weeks past
maximum and showing a deep absorption at 635 nm. The CfA redshift
survey gives a radial velocity of about 10 400 km/s for IC 2735.
IAUC 4982
CATACLYSMIC VARIABLE IN CORVUS
D. H. Levy, Tucson, AZ, communicates the discovery by C. W.
Tombaugh of a cataclysmic variable in Corvus on a plate taken 1931
Mar. 23 with the 0.33-m A. Lawrence Lowell astrograph at Lowell
Observatory, when the star's magnitude was about 12. A search by
Levy through 260 plates in Harvard College Observatory's archives
revealed 9 other maxima on the following dates: 1932 Mar. 2, 1940
Feb. 12, 1941 Feb. 5, 1952 Apr. 21, 1971 Apr. 20, 1983 Feb. 22, 1985
Mar. 15, 1987 Mar. 6, and 1988 May 21. Levy reports another outburst
on 1990 Mar. 23.270 UT, with the star at mv = 13.6. Precise posi-
tions measured by B. Skiff, Lowell Observatory (equinox 1950.0):
discovery plate, R.A. = 12h17m48s.38, Decl. = -18 10'27".4; Palomar
Sky Survey O exposure, 1954 Mar. 7, R.A. = 12h17m48s.64, Decl. =
-18 10'22".7 (estimated blue mag about 17-18, red mag about 19).
IAUC 4983
Guy M Hurst