Circular No. 5407
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET    MARSDEN or GREEN@CFAPS2.SPAN
 
 
PERIODIC COMET KOWAL 2 (1991f1)
     Ephemeris from the orbital elements on IAUC 5406:
 
     1991 ET      R.A. (1950) Decl.     Delta      r       m1
     Dec. 10     8 31.62    + 0 39.2    0.756    1.546    14.3
          15     8 32.92    - 1 27.5
          20     8 33.07    - 3 26.2    0.739    1.574    14.3
          25     8 32.13    - 5 14.8
          30     8 30.20    - 6 51.4    0.736    1.608    14.4
 
 
LB 1800
     R. Baptista, Instituto Astronomico e Geofisico, Sao Paulo; and
D. Cieslinski, Instituto Nacional de Pesquisas Espaciais/SECT, San
Jose dos Campos, communicate:  "We have discovered that the ephemer-
is of Buckley et al. (1990, Ap.J. 355, 617) for the timings of mini-
mum light in the eclipsing cataclysmic variable LB 1800 has accumu-
lated an error which now amounts to +0.26 cycles.  We used the
FOTRAP photometer at the 0.6-m telescope at CNPq/Laboratorio Naci-
onal de Astrofisica, Brazil, to obtain high speed (10-s) UBVRI pho-
tometry of this object.  The data comprise three observed eclipses,
on 1991 Jan. 13, Dec. 4, and Dec. 5.  We determined the times of
minimum by adjusting a parabola and a cubic function to the points
during eclipse and calculating their minimum, and by employing bi-
sected chords to find the average of the mean point from a group of
chords at different depth levels.  We list below the measured tim-
ings, the corresponding cycle, and O--C values with respect to the
new ephemeris (the uncertainties quoted in parentheses are the er-
rors of the mean of the determinations from the methods employed):
HJD 2448269.63136(15), 6177, +0.0024; HJD 2448595.73325(11), 7583,
+0.0015; HJD 2448596.66022(09), 7587, -0.0018.  Together with the
original 9 timings of Buckley et al., this gives the new ephemeris
Tmin = HJD 2446836.96176(25) + 0.231936060(35)E, with a correspond-
ing dispersion of 0.00636 cycles for the 12 timings used."
 
 
PERIODIC COMET FAYE (1991n)
     Total visual magnitude estimates (cf. IAUC 5382) by A. Hale,
Las Cruces, NM (B = 10x50 binoculars; L = 0.41-m reflector):  Nov.
27.21 UT, 9.7 (B); Dec. 4.27, 9.9 (L); 13.29, 10.3 (L).
 
 
1991 December 17                                  Daniel W. E. Green