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IAUC 4801: Occn OF 28 Sgr BY TITAN

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                                                 Circular No. 4801
Central Bureau for Astronomical Telegrams
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

     Numerous observations of this event (cf. IAUC 4761) have been
received.  In addition to those tabulated below, positive reports
have been received from observers in Naples, Italy; Barcelona,
Spain; and the Canary Islands (M. Kidger reports that at Tenerife
the atmospheric occultation, or fading, was longer than the disk,
or total, occultation).  Below is a list of available timings
(given as UT + July 3d22h); t1 and t4 are the beginning and end
times of the star's fading, and t2 and t3 are the beginning and
end times of the total occultation.  Some observers noted a central
flash of light.  S. Boyle states that the Mill Hill estimates
are +/- 1 s, those observers noting that 28 Sgr changed in color
from orange to blue-white during the fade in brightness.

Observer           t1           t2        flash        t3          t4
Appleby          39m0s        40m00s
Brierley                      39 59.0    42m09.9     44m18.6
Debehogne                                            44 21.1
Geyer            38 52        39 43      41 36       43 44       44m43s
Griffen          39 31        40 10                  44 05       44 48
Hurst            39 29        40 00      42 08       44 14       45 05
Schlyter         38 20        38 50      41 00       43 05       43 45
Smalley          39 22                               43 50       44 55
Smith            39 19                                           44 49
Wonnacott        39 24                                           44 56

G. Appleby (Royal Greenwich Observatory).  Satellite Laser Ranger
  Telescope, Herstmonceux.  Central brightening of about 1 mag
  lasted about 10 s.
D. Brierley (Malvern, England).  Long. = -2.3264 deg, Lat. =
  +52.1358 deg, h = 70 m.  0.07-m telescope.
H. Debehogne and A. Dekersgieter (Observatoire Royal de Belgique,
E. H. Geyer and M. Hoffmann (Hoher List Observatory).  1.06-m
  telescope.  Second central flash at 41m40s.
I. Griffin, B. Smalley, K. C. Smith, and D. Wonnacott (U. of
  London Obs., Mill Hill).  0.61-m f/11 refractor (268x), 0.20-m
  f/10 reflector (167x), 0.15-m f/11 refr. (66x), and 0.20-m f/10
  refl. (111x), respectively.
G. M. Hurst and M. Hurst (Basingstoke, England).  15x80
  binoculars.  Flickering noted during pre-occultation fading
  and at 44m47s.
P. Schlyter (Stockholm).  Central flash was 'probable'.

1989 July 5                    (4801)             Daniel W. E. Green

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