[vsnet-chat 2175] Matching CoD and CPD stars

[Mati Morel <morel@ozemail.com.au>]

        Years ago, when the CoD and CPD catalogues were the only reasonably
complete
sources of stars down to mag. 11, I did lot of matching of stars. I
generally started
off by compiling a list of CoD stars (as I wanted to produce a chart for visual
observers), and then went through the list by eye, comparing each star with CPD
entries, so as to improve the accuracy of as many positions as possible. The
Vizier
utility mentioned by Brian Skiff has only become available in recent times.
I did notice that "missing" stars tended to occur much more frequently in
the CoD
than the CPD. In fact, I can hardly recall any examples of missing CPD
stars, perhaps
only one or two over the last twenty years. This reflects the methods used
to compile
the two catalogues. The CoD was compiled mostly by Juan M. Thome, at the Cordoba
Observatory in Argentina, much of it singlehanded. Unlike Argelander at
Bonn, who
had younger assistants to do the actual observing, Thome had to do much of
the observing himself, with little assistance, as well as the data
reduction, in 
zones which frequently had four times as many stars as the corresponding
northern
zones.  Anyone who has tried observing a fixed spot through an optical 'scope,
for prolonged periods of time, will understand how physically taxing it becomes.
Thome's untiring efforts over 23-year period (till his death in 1908) inspired
awe among friendly Argentines, while knowing nothing of astronomy, they looked
upon him "as a combination of wizard and long distance runner". (J. Hodge 1971).

Bibliography:
1. Morel, M. 1990. "A New Lease of Life for Some Old Star Catalogues",
Contr. to Proceedings of NACAA XIV, p.47 (Melbourne, April 13-16, 1990).
2. Hodge, J.E. 1971. "Juan M. Thome, Argentine Astronomer from the Quaker
State",
Journal of Inter-American Studies and World Affairs 13, 215-229 (1971 April).
[An excellent biographical treatment of Thome's life and work].  
/Mati

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