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Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.stsci.edu/ftp/documents/p2pi/HTMLjavahelpCy20/ch03_targ_fixed06.html
Дата изменения: Thu May 31 18:25:59 2012 Дата индексирования: Mon Apr 11 19:58:16 2016 Кодировка: |
| Space Telescope Science Institute |
| Cycle 20 Phase II Proposal Instructions |
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The year of the equator and equinox to which the coordinates are referred must be J2000 (Julian).It is not necessary to apply precession corrections to coordinates from positional catalogs. The Guide Star Catalog and the Hipparcos Input Catalogue both use the J2000 equinox. (Note, however, that the Hipparcos output catalogue is epoch 1991.25, which means proper motions can have significant effects if you are not careful.)
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