I/263 ACR catalog around Celestial Equator (Stone+, 1999)
Improved astrometric calibration regions along the celestial equator.
Stone R.C., Pier J.R., Monet D.G.
<Astron. J. 118, 2488 (1999)>
=1999AJ....118.2488S 1999AJ....118.2488S
ADC_Keywords: Fundamental catalog ; Positional data ; Proper motions ;
Magnitudes
Keywords: astrometry - stars: general
Abstract:
We present improved and highly accurate International Celestial
Reference System (ICRS) equatorial positions for 1,268,732 stars in 16
astrometric calibration regions located around the celestial equator.
Each region is about 7.6°x3.2° in area (∼24.3 deg2),
contains a large number of stars (18,767 to 263,810), has stellar
densities ranging from 765 to 10,772 stars deg-2, covers a wide
range in magnitude (9.5<R<17.8, or equivalently 10.0<V<18.3), and is
complete to magnitude R∼17.2 (V∼17.7). All of the observations were
taken in 1994-1998 (mean epoch J1996.0) with the Flagstaff Astrometric
Scanning Transit Telescope. Furthermore, each region was observed many
times with overlapped CCD strip scans, and these data were reduced to
star positions using differential reductions. The reference-star
positions were taken from the ACT catalog of accurate star positions
and proper motions. The star positions presented herein are typically
accurate to ±26mas (±12mas precision) in both right ascension and
declination, except for the faintest stars, whose errors are about 2
times larger. Similarly, magnitudes were determined for the
astrometric calibration stars using standard photometric reductions,
and accuracies of ±18mmag (±10mmag precisions) were achieved
(about ±46mmag for the faintest stars)
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
acr_a.dat 121 19168 ACR catalog, region A (around 00h46 +00)
acr_b.dat 121 18767 ACR catalog, region B (around 01h37 +00)
acr_c.dat 121 26378 ACR catalog, region C (around 03h38 +00)
acr_d.dat 121 39411 ACR catalog, region D (around 04h29 +00)
acr_e.dat 121 263810 ACR catalog, region E (around 07h14 +00)
acr_f.dat 121 109250 ACR catalog, region F (around 08h05 +00)
acr_g.dat 121 26162 ACR catalog, region G (around 10h15 +00)
acr_h.dat 121 22309 ACR catalog, region H (around 11h06 +00)
acr_i.dat 121 22106 ACR catalog, region I (around 12h38 +00)
acr_j.dat 121 24948 ACR catalog, region J (around 13h29 +00)
acr_k.dat 121 47371 ACR catalog, region K (around 15h22 +00)
acr_l.dat 121 65773 ACR catalog, region L (around 16h13 +00)
acr_m.dat 121 246334 ACR catalog, region M (around 17h57 +00)
acr_n.dat 121 261362 ACR catalog, region N (around 18h47 +00)
acr_o.dat 121 45731 ACR catalog, region O (around 21h51 +00)
acr_p.dat 121 29881 ACR catalog, region P (around 22h42 +00)
table1.dat 83 16 Astrometric calibration regions
table8.dat 39 17 Internal and true accuracies of ACR star
positions and magnitudes at epochs
J1996 and J2006
--------------------------------------------------------------------------------
See also:
I/246 : The ACT Reference Catalog (Urban+ 1997)
Byte-by-byte Description of file: acr_*.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- ACR Star designation (ACR xxyyyyyy) (1)
11- 20 I10 --- ACR1 Old star designation used in Paper I
(1997AJ....114.2811S 1997AJ....114.2811S)
23- 32 F10.7 h RAhr ICRS J2000 right ascension
34- 43 F10.6 deg DEdeg ICRS J2000 declination
46- 50 F5.2 mag RFmag RF-magnitude (G1)
53- 55 I3 mas e_RAhr True error in RA*cosDE
58- 60 I3 mas e_DEdeg True error in declination
63- 67 F5.3 mag e_RFmag True error in the RF-magnitude
70- 71 I2 --- o_RAhr Number of observations used to compute RA
74- 75 I2 --- o_DEdeg Number of observations used to compute DE
78- 79 I2 --- o_RFmag Number of observations used to compute
RF-magnitude
82- 87 F6.3 yr EpRA-1900 Mean epoch for the RA (1900+)
90- 95 F6.3 yr EpDE-1900 Mean epoch for the declination (1900+)
98-103 F6.3 s/hyr pmRA Proper motion in RA (seconds/cy) (2)
106-111 F6.2 arcsec/hyr pmDE Proper motion in DE (arcsec/cy) (2)
114-116 F3.1 mas/yr e_pmRA ?=0 Error in the proper motion in RA (2)
119-121 F3.1 mas/yr e_pmDE ?=0 Error in the proper motion in DE (2)
--------------------------------------------------------------------------------
Note (1): xxyyyyyy is a star number encoded such that xx is the astrometric
calibration region (A=1, B=2, ..., P=16, see file "table1.dat"), and
yyyyyy is a serial number identifying each star (increases with right
ascension).
The number xxyyyyyy should always be preceded with the `ACR'
descriptor that uniquely identifies each astrometric calibration star
(for example, the first star given in region P has the number ACR
16000001).
Note (2): All errors are standard errors, and if a proper motion could not
be computed, albeit rarely, then proper motions columns were set equal
to zero in the catalog.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Region Regional designation (A to P)
3- 4 I2 h RA1h Beginning (top) J2000 Right ascension boundary
6- 7 I2 min RA1m Beginning (top) J2000 Right ascension boundary
9- 12 F4.1 s RA1s Beginning (top) J2000 Right ascension boundary
14 A1 --- DE1- Beginning (top) J2000 declination sign
15 I1 deg DE1d Beginning (top) J2000 declination
17- 18 I2 arcmin DE1m Beginning (top) J2000 declination
20- 21 I2 arcsec DE1s Beginning (top) J2000 declination
24- 25 I2 h RA2h Ending (lower) J2000 Right ascension boundary
27- 28 I2 min RA2m Ending (lower) J2000 Right ascension boundary
30- 33 F4.1 s RA2s Ending (lower) J2000 Right ascension boundary
35 A1 --- DE2- Ending (lower) J2000 declination sign
36 I1 deg DE2d Ending (lower) J2000 declination
38- 39 I2 arcmin DE2m Ending (lower) J2000 declination
41- 42 I2 arcsec DE2s Ending (lower) J2000 declination
44- 46 F3.1 deg Size1 Angular dimensions of the region
47 A1 --- --- [x]
48- 50 F3.1 deg Size2 Angular dimensions of the region
52- 57 I6 --- Nstars Number of stars in the region
59- 65 F7.1 ct/deg2 Density Mean stellar density
67- 70 F4.1 mag RFmag Limiting RF-magnitude reached (G1)
72- 76 F5.1 deg GLON Galactic longitude at the center of each region
78- 82 F5.1 deg GLAT Galactic latitude at the center of each region
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 F4.1 mag RFl RF magnitude range (lower) (G1)
5 A1 --- --- [-]
6- 9 F4.1 mag RFu RF magnitude range (upper) (G1)
12- 13 I2 mas RAI Internal accuracy for Right ascension
15- 16 I2 mas DEI Internal accuracy for Declination
18- 19 I2 mmag RFI Internal accuracy for RF magnitude (G1)
22- 23 I2 mas RA1 True accuracy for RA at epoch J1996
25- 26 I2 mas DE1 True accuracy for DE at epoch J1996
28- 29 I2 mmag RF1 True accuracy for RF magnitude at epoch J1996
32- 33 I2 mas RA2 True accuracy for RA at epoch J2006
35- 36 I2 mas DE2 True accuracy for DE at epoch J2006
38- 39 I2 mmag RF2 True accuracy for RF magnitude at epoch J2006
--------------------------------------------------------------------------------
Global Notes:
Note (G1): the RF magnitude is close to Cousins R magnitude, or
the r' band in the Sloan Digital Sky Survey: centered
around 622nm, range around 550-700nm.
History: From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 20-Jan-2000