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RE : http://www.fer3.com/arc/m2.aspx?i=116505
[NavList] Re: Any "on line" Star Position Computation available ?
From: navigationalalgorithms---com
Date: 13 Jun 2011 09:05

Hello Andr�s,

Yes it looks like there might be no on-line full accuracy Star Apparent Position Web site. I would still not give up looking up and searching ...

*******

You mentioned the FK6 Catalog, and it brings me to the following point :

Since the first HIPPARCOS Catalog in 1997, EASA published in 2007 a (higly) improved HIPPARCOS Catalog.

See :

http://heasarc.gsfc.nasa.gov/W3Browse/all/hipnewcat.html ,and also :

http://cds.aanda.org/index.php?Itemid=129&option=com_article&access=bibcode&bibcode=2007A%25252526A...474..653V

where you can get the following very interesting free access article :

A&A 474, 653-664 (2007)
DOI: 10.1051/0004-6361:20078357
Validation of the new Hipparcos reduction
F. van Leeuwen

Given the high accuracy achieved by the 2007 Improved Hipparcos Catalog, which to the best of my kowlegde is a main current data source for ICRS, I am no longer sure that FK6 can still be claimed to be the most accurate Star Catalog. Maybe FK6 still remains the best one for proper motions, but I would think that for plain 2000.0 RA & Dec values, HIPNEWCAT (i.e. Hipparcos 2007 Improved Catalog) probably gives us the very best data available to-day.

Any "expert advice" on my previous thoughts here about this HIPNEWCAT / FK6 comparison ?

and again ... any way to perform on-line super accurate Stars Apparent Positions computations ???

Best Regards to all

Kermit

Antoine M. "Kermit" Cou�tte

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