Central Bureau for Astronomical Telegrams
IAUC 3099: P/TSUCHINSHAN 1; HEAO-1 LAUNCH; Var X-RAY SOURCES; V1500 Cyg
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Read IAUC 3100
Circular No. 3099
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 Telex: 921428
Telephone: (617) 864-5758
PERIODIC COMET TSUCHINSHAN 1
The following ephemeris is from the predicted elements by G.
Sitarski (1975, Acta Astron. 25, 161). There is a very similar
prediction in Acta Astron. Sinica (1976) 17, 106.
For dT = +1d
1977/78 ET R. A. (1950) Decl. Delta r dR.A. dDecl. m2
Oct. 4 2 14.50 - 3 39.6 1.600 2.540 -1m44 - 8'5 21.1
14 2 07.07 - 4 42.7 -1.51 - 8.6
24 1 57.83 - 5 37.8 1.444 2.412 -1.53 - 8.5 20.6
Nov. 3 1 47.76 - 6 16.5 -1.52 - 8.2
13 1 38.11 - 6 31.4 1.390 2.283 -1.47 - 7.9 20.3
23 1 30.13 - 6 18.3 -1.39 - 7.6
Dec. 3 1 24.79 - 5 36.7 1.423 2.155 -1.30 - 7.4 20.1
13 1 22.63 - 4 28.9 -1.22 - 7.4
23 1 23.89 - 2 58.1 1.507 2.029 -1.15 - 7.5 20.0
Jan. 2 1 28.48 - 1 08.2 -1.10 - 7.7
12 1 36.21 + 0 57.2 1.609 1.909 -1.07 - 8.1 19.8
22 1 46.87 + 3 15.1 -1.07 - 8.5
Feb. 1 2 00.22 + 5 42.5 1.707 1.796 -1.08 - 8.9 19.7
11 2 16.10 + 8 16.7 -1.11 - 9.3
21 2 34.37 +10 54.8 1.792 1.694 -1.16 - 9.7 19.6
Mar. 3 2 54.96 +13 33.7 -1.23 - 9.9
13 3 17.82 +16 09.8 1.863 1.610 -1.31 -10.0 19.4
23 3 42.92 +18 39.2 -1.40 - 9.9
Apr 2 4 10.20 +20 57.3 1.926 1.546 -1.50 - 9.6 19.3
12 4 39.57 +22 59.4 -1.61 - 8.9
22 5 10.85 +24 40.4 1.988 1.508 -1.72 - 8.0 19.3
May 2 5 43.73 +25 55.8 -1.81 - 6.7
12 6 17.82 +26 41.9 2.061 1.500 -1.89 - 5.1 19.3
22 6 52.57 +26 56.4 -1.93 - 3.4
June 1 7 27.41 +26 38.7 2.153 1.522 -1.94 - 1.6 19.5
11 8 01.82 +25 50.0 -1.91 + 0.2
21 8 35.31 +24 33.3 2.268 1.572 -1.85 + 1.9 19.7
July 1 9 07.54 +22 52.7 -1.77 + 3.3
11 9 38.32 +20 53.0 2.408 1.646 -1.67 + 4.4 20.1
HEAO-1 LAUNCH
G. J. Fishman writes: "The HEAO-1 spacecraft (formerly HEAO-A)
was successfully launched into a near-circular orbit on Aug. 12.
The orbital period is 93 min and the inclination 22o.8. All spacecraft
systems appear to be operating normally. The four experiments
are currently undergoing checkout and activation operations.
During the first three months of the planned six-month operational
lifetime the spacecraft will scan a band of the sky 90o from the
sun. The width of this band is from 0o.5 to 20o, depending upon the
experiment module. Observers planning to perform coordinated
observations with HEAO-1 may obtain the operational status of the
spacecraft and experiments from C. Dailey, Code HA-01, Marshall
Space Flight Center, AL 35812, U.S.A. (telephone 205-453-1680)."
VARIABLE X-RAY SOURCES
L. J. Kaluzienski and S. S. Holt, Goddard Space Flight Center,
communicate the following:
(1) The Ariel 5 all-sky monitor has detected a flare from the
region centered on l = 357o.5 +/- 0o.5, b = -3o.2 +/- 2o.0 (R.A. = 17h49m,
Decl. = -32o.7, equinox 1950.0; 90-percent-confidence error box).
Observations in the instrument fine spatial resolution mode on the latter
half of Aug. 19 yield a source flux (3-6 kev; half-day averages) of
0.4 +/- 0.05 times that of the Crab Nebula and early on Aug. 22 of
0.6 +/- 0.1 times the Crab. Similar observations on Aug. 12 yield a
possible detection (0.1 +/- 0.1 times the Crab), while course-mode
observations show the possible presence of a source beginning Aug.
14 (although confusion with known nearby sources cannot be ruled
out). The derived position of the flare is consistent with that of
4U 1755-33 and, if due to this source, the flare represents an order
of magnitude increase above the peak level observed by Uhuru.
(2) Continued monitoring of the Norma-Circinus region has
revealed a decline in the average intensity of the flaring source 4U
1608-52 (IAUC 3090, 3094). Following the initial rapid rise phase
(half-day-average maximum flux at 3-6 keV ~ 1.0 times the Crab)
during July 5-10 the source maintained a relatively stable plateau
level of ~ 0.6 times the Crab through early August. During this
time no significant variations on timescales >~ 0.5 day were exhibited,
although orbit-to-orbit variability was observed. The average
intensity during Aug. 12-22 decreased to ~ 0.45 times the Crab,
and this may thus signal the commencement of the decline phase.
The duration of outburst is already considerably longer than that
of Nov. 1975 (IAUC 2859), which lasted less than one month.
(3) From additional observations of turn-offs in the 16.6-day
cycle of Cir X-1 (IAUC 2939) we have refined the ephemeris to T =
1977 May 28.618 (+/- 0.09) UT + 16.595 (+/- 0.004) E. T is the time of
abrupt transition from high to low flux, and errors are 3-sigma.
V1500 CYGNI
Recent visual magnitude estimates: May 23.12, 12.9 (J. Bortle,
Brooks Obs.); June 16.16, 12.8 (S. O'Meara, Harvard Obs.); July
9.10, 13.3 (Bortle); 24.11, 13.3 (Bortle); Aug. 2.12, 12.8 (O'Meara).
1977 August 29 (3099) Brian G. Marsden
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