Circular No. 6898
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
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Phone 617-495-7244/7440/7444 (for emergency use only)


SUPERNOVA 1998bt
     L. Germany reports that the Mount Stromlo Abell Cluster
Supernova Search Team (cf. IAUC 6639, 6893) has discovered an
apparent supernova (V = 19.7), presumably associated with the Abell
cluster 1736, on V and R CCD images taken on Mar. 10 with the Mount
Stromlo 1.27-m telescope (+ Macho Camera).  No background host
galaxy has been identified for the object, which is located at R.A.
= 13h25m41s.93, Decl. = -26o46'55".7 (equinox 2000.0).  SN 1998bt
is present on images taken on Feb. 23 and Apr. 6, 18, and 30, with
limiting V magnitudes of 21.0, 21.0, 21.5, and 21.5, respectively.
The object increased in brightness by > 1.5 mag between Feb. 23
and Apr. 6, and has faded by about half a magnitude since then.
The star was not present on an image taken on Jan. 27 (limiting mag
V = 21.5).


SUPERNOVA 1998Z IN ANONYMOUS GALAXY
     Germany also writes: "I obtained a spectrum (range 380-750 nm)
of SN 1998Z (cf. IAUC 6850) with the Mount Stromlo 2.3-m telescope
(+ DBS) on Apr. 1.  The spectrum confirms this object to be a
type-Ia supernova within a week of maximum light."


GRB 980425
     P. M. Vreeswijk, University of Amsterdam, writes that he
provided the wrong position for the optical position of the
suspected supernova in ESO 184-G82 on IAUC 6895, lines 7-8; the
correct position should read R.A. = 19h35m03s.17, Decl. =
-52o50'46".1 (equinox 2000.0).


SAX J1808.4-3658 = XTE J1808-369
     A. V. Filippenko adds that the spectra reported on IAUC 6897
were obtained on May 2 UT.


SUPERNOVA 1998aq IN NGC 3982
     CCD V photometry: Apr. 20.904 UT, 12.67 (D. Hanzl, Brno, Czech
Republic); 25.911, 12.25 (Hanzl); 26.957, 12.22 (Hanzl); 27.15,
12.14 +/- 0.14 (D. B. Caton, Dark Sky Observatory, Appalachian
State University); 28.027, 12.18 (Hanzl); 30.886, 12.20 (Hanzl);
May 2.956, 12.23 (Hanzl); 5.947, 12.36 (Hanzl).
On Apr. 20.904, Hanzl also reported B-V = +0.02.

                      (C) Copyright 1998 CBAT
1998 May 8                     (6898)            Daniel W. E. Green