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I/273 Extragalactic Reference Link Catalog (ERLcat) (de Vegt+, 2001)
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A catalog of faint reference stars in 398 fields of
extragalactic radio reference frame sources.
de Vegt C., Hindsley R., Zacharias N., Winter L.
<Astron. J. 121, 2815 (2001)>
=2001AJ....121.2815D
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ADC_Keywords: Fundamental catalog ; Positional data
Keywords: astrometry - catalogs
Description:
This is an astrometric catalog, providing positions of 89,422 stars in
398 selected fields of extragalactic reference frame sources. The
stars are mainly in the 11 to 14 magnitude range. The average
positional accuracy is about 50 mas per coordinate at the epoch of
observation, which is between 1976.2 and 1991.9. The observations are
based on photographic plates, taken with 2 telescopes which are:
- the Hamburg Zone astrograph (in the Northern Hemisphere)
- the USNO Twin astrograph at Black Birch (New Zealand)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
erlcat.dat 68 89422 Extragalactic Reference Link Catalog (ERLcat)
fields.dat 36 447 Summary of the fields observed
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See also:
http://ad.usno.navy.mil/erlcat/index.html : ERLcat home page
Byte-by-byte Description of file: erlcat.dat
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Bytes Format Units Label Explanations
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2- 10 I9 --- ERL Star number
12- 15 I4 0.01mag Pmag Photographic magnitude (filters OG515 or GG495)
17- 26 I10 mas RAmas Right ascension in ICRS, at Epoch (1)
28- 37 I10 mas DEmas Declination in ICRS, at Epoch (1)
39- 41 I3 mas e_RAmas Formal error in RA*cos(DE)
43- 45 I3 mas e_DEmas Formal error in DE
47- 48 I2 --- Nplates Number of plates used
50- 56 A7 --- Box Name of box (field) (2)
58- 66 F9.4 yr Epoch [1976.2,1993.4] Epoch of observation
68 A1 --- Tel [BZ] Telescope (G1)
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Note (1): The coordinates are on the Hipparcos System, thus on the ICRS,
which is consistent with the J2000 coordinate system.
Note (2): For several fields, multiple files (boxes) are provided.
These are observations of the same field made with different
telescopes and/or at widely separated epochs.
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Byte-by-byte Description of file: fields.dat
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Bytes Format Units Label Explanations
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2- 8 A7 --- Box Name of box
9- 16 A8 --- Field Field name (based on position)
19 A1 --- Tel [BZ] Telescope (G1)
23- 31 F9.4 yr Epoch [1976.2,1993.4] Observation date
33- 36 I4 --- Nst Number of stars in the field
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Global Notes:
Note (G1): the instrument are designated by:
Z = Hamburg Zone astrograph (geographic latitude +53.5{deg})
with filter OG515 close to focal plane
B = USNO Twin astrograph at Black Birch, New Zealand (-41.7{deg})
with filter GG495 integrated in lens
History:
Copied at http://ad.usno.navy.mil/erlcat/index.html
and merged the epoch into the main file.
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(End) James Marcout, Patricia Bauer [CDS] 30-Aug-2001