Re: Tycho 2 catalog astrometry

[hjohnson@pluto.njcc.com (Herbert R Johnson)]

On Fri, 30 Jun 2000 11:21:36 -0400, Stupendous Man <richmond@a188-l009.rit.edu> wrote:
*>
*>  Andrew Bennett discovered that Tycho-2 produces better astrometry
*>with Mark IV images than Tycho-1:
*>
*>> This makes quite a big difference. For example, for
*>> file H3R1659.840 (CD15) my program using Tycho:
*>> Matched 235, accepted 215 sd 0.918 pe 0.745 arc sec
*>> For Tycho 2:
*>> Matched 352, accepted 324 sd 0.686 pe 0.541 arc sec
*>
*>  I followed his example and ran astrometric routines on the
*>same image, H3R1659.840 (the image containing M5).  The results
*>follow his ... under one condition:

[snip]
*>
*>  Now, I need to find enough disk space here to hold the Tycho-2
*>catalog ....
*>
*>                                                  Michael Richmond

FOr those of us who are not a part of the professional astronomical
community AND also do not have access to fast Internet connections;
perhaps Michael or Andrew can suggest ways we can also obtain the
Tycho-2 catalog. If distribution rights allow, perhaps a CD-ROM or
two can be constructed for TASS members if necessary. A Tech Note
with these recent findings and appropriate references would be appreciated.

How "complete" is the new catalog? That is, at what magnitude does it,
include, say, 95% of all stars (or whatever metric is convenient for
completness)?

Herb Johnson

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