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MAST
Catalogs and Surveys Group |
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Quick
Fact Sheet on GSC versions
Note
- always use the most recent version of GSC 2 (currently
2.3.2) for HST target coordinates!
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GSC 1.1
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GSC
2.3.2
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| Total Objects |
18,819,291
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945,592,683
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| Mean
epoch of catalog positions |
1981.8
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1992.5
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| Magnitude limit |
15.5
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20.5 F, 21.5 J, 19 N
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| Complete
to magnitude limit |
No
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Yes*
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| Bandpass:
North |
V
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F,
J, N, O, E, V
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| Bandpass:
South |
J**
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F,
J**, N, O***, E***
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| Digitization resolution |
1.7 arcsec
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1
arcsec****
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| Source for bright stars |
Hipparchos Input Catalog
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Tycho
2
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| Astrometry: |
-
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-
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Reference frame
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FK4
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ICRF
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Reference catalogs
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AGK3, SAO: 10^2 calibrators
per plate
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ACT,
Tycho2: 10^3 calibrators per plate
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Projection
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Gnomonic
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Equidistant
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Systematic error correction
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None
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mask,
refraction precorrection
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Errors:
typical
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0.5"
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0.3"
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Errors:
worst case
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1.2"
near plate edges
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0.35" -
0.75"
near plate edges
for mag > 16
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| Photometry: |
-
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Reference catalogs
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GSPC1: 6 calibrators
per plate
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GSPC2:
10^2 calibrators per plate
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Errors
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0.5 mag
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0.2
- 0.25 mag
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* Except for the most difficult areas such
as around bright stars, globular clusters, etc
** 93 short exposure V plates replace
the deep J plates in the galactic plane
*** POSS-I southern extension down to -24degrees
**** Approximately half the southern
J plates are included at the original 1.7" resolution
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Last Modified:
2016-06-20 14:42
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