Central Bureau for Astronomical Telegrams
IAUC 2221: TRANSIT OF MERCURY; AGK2-AGK3
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Read IAUC 2222
Circular No. 2221
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
Western Union: RAPID SATELLITE CAMBMASS
TRANSIT OF MERCURY
P. M. Janiczek and A. D. Fiala communicate: "We request
observations of the transit of Mercury on May 9. The primary interest
is in series of photographs taken between second and third contacts,
bracketing the time of conjunction. Observations with equatorial
refractors and photoheliographs of focal length greater than
3 meters are especially encouraged. Times should be recorded to ls
(UT) or better, and the orientations of the images should be indicated
by wires or fiducial marks. We are prepared to measure and
reduce the plates. Meridian observations and visual timings of the
contacts are also of interest. The location of the instrument,
aperture used, focal length, and seeing conditions should be specified.
For questions on detail write to us at: U.S. Nautical Almanac
Office, U.S. Naval Observatory, Washington, D.C. 20390, U.S.A."
AGK2-AGK3
P. Lacroute and A. Valbousquet write: "L'Observatoire de
Strasbourg, 11 rue de l'Universite, Strasbourg, France, can prepare
magnetic tapes with the AGK2-AGK3 as determined at Hamburg and refined
at Strasbourg using overlapping plates. The data furnished
are: the AG and BD numbers, the coordinates at epochs 1930.0 and
1958.0 and their uncertainties, the proper motions and their
uncertainties, the magnitude, the spectral type and the number of
observations used in each mean. The tapes are in the IBM 360 operating
system. They can be in seven tracks at 800 b.p.i. or nine
tracks at 1600 b.p.i. The data available at present extend from
the north pole to +40o declination, inclusive. They can be contained
on one 1200-foot reel provided that it is: 1) in nine tracks
at 1600 b.p.i.; 2) in binary, IBM 360 system; 3) with a large block
size (of the order of 6000 to 7000). Shortly we shall be able to
furnish data for the exact mean epochs of observations. Then the
data will be extended toward lower declinations, when we have received
the material. Some plates, especially between declinations
+52o and +60o, are in the course of remeasurement at Hamburg; thus
the current solution is not completely definitive. Some chance
uncertainties will be somewhat diminished, but the system will not be
modified." [Translation from the French.]
1970 March 5 (2221) Brian G. Marsden
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