Central Bureau for Astronomical Telegrams
IAUC 3252: OPTICAL/X-RAY Obs IN 1979; MPC 4391-4424
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Read IAUC 3253
Circular No. 3252
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
OPTICAL/X-RAY OBSERVATIONS IN 1979
The SAS-3 Group of the Massachusetts Institute of Technology
has reserved "dark time" in 1979 for simultaneous optical and x-ray
observations of x-ray sources with faint optical counterparts. The
periods are 1979 Apr. 19-May 3, May 19-June 3, June 18-July 2 and
July 17-Aug. 1. The second period will be devoted only to northern-hemisphere
objects, the other three to southern-hemisphere objects.
At present it is expected that the three optically identified x-ray
burst sources will be studied intensively; these are MXB1636-53,
1659-29, 1735-44 (IAUC 3084, 3088 and 3229) and 1837+05 (identification
less certain: IAUC 2824 and 3246). Participation by optical
observers is invited. Large telescopes (aperture >~ 150 cm) are
needed because the optical counterparts are faint {mv > 17). Recently
an optical burst was observed simultaneously with an x-ray
burst from MXB 1735-44 (IAUC 3230). Astronomers who are interested
in participating should contact W. Lewin (telephone 617-253-4282;
telex 92-1473 MIT CAM; TWX 710-320-0058 MIT CAM) as soon as possible
for more information.
MPC 4391-4424
MPC (Minor Planet Circulars/Minor Planets and Comets) 4391-4424,
dated Aug. 1, were mailed to subscribers yesterday. They include
information about faint comets that would in the past have
been published on the IAU Circulars. As noted on IAUC 3205, regular
(billed) subscriptions to the MPCs cost 8c per issue, and bills
will be sent annually following an initial payment of approximately
$24.00 (for 300 issues). Special (unbilled) subscriptions cost 5c
per issue, and special subscribers can keep track of their accounts
by noting that the last four figures of the 12-figure number on
their address label give the MPC number up to which they have paid.
Special subscribers should make appropriate payments ($5.00 for 100
issues, $10.00 for 200, etc.) when necessary. Enquiries and payments
can be made either to the Central Telegram Bureau or to the
Minor Planet Center at the Smithsonian Astrophysical Observatory,
60 Garden Street, Cambridge, MA 02138, U.S.A. It is expected that
the next batch of MPCs will be issued on or about Sept. 1.
1978 August 8 (3252) Brian G. Marsden
Read IAUC 3253
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