I/283A Lick NPM2 Catalog (Hanson+ 2003)
Lick Northern Proper Motion Program. III. Lick NPM2 Catalog
Hanson R.B., Klemola A.R., Jones B.F., Monet D.G.
<Lick Observatory (May 2003)>
=2004AJ....128.1430H 2004AJ....128.1430H
ADC_Keywords: Positional data ; Proper motions ;
Magnitudes, photographic ; Colors ; Cross identifications
Description:
The NPM2 Catalog is the second part of the Lick Northern Proper Motion
(NPM) program to measure absolute proper motions, on an inertial
system defined by distant galaxies, for nearly 400,000 stars over a
blue apparent magnitude range from 8 to 18. There are 1246 6x6degree
fields in the NPM survey (to declination -23 degrees). The NPM2
Catalog covers the 28% of the northern sky lying near the plane of the
the Milky Way and contains some 232,000 stars in the 347 NPM fields
remaining after the 1993 NPM1 Catalog (149,000 stars in 899 fields
away from the Milky Way).
Each NPM field was photographed with the 51cm Carnegie Double
Astrograph at two epochs between 1947 and 1988. The mean first and
second epochs are 1950 and 1977; the average epoch difference is 27
years. The first-epoch plates were taken in the blue only; both blue
and yellow plates were taken at the second epoch. For NPM2, the plates
were scanned by the Precision Measuring Machine (PMM) at the US Naval
Observatory, Flagstaff. From the PMM scans, 120,000 faint (B>14) stars
were chosen anonymously for the NPM astrometric reductions and for
statistical studies of stellar motions. The NPM2 catalog also contains
92,000 bright (B<14) positional reference stars, mostly from the
Tycho-2 Catalogue, and 35,000 stars chosen for astronomical interest
from Klemola's "Lick Input Catalog of Special Stars". (These
categories overlap). Details of the NPM2 star selection, data
reductions, and catalog compilation will be presented in a paper being
prepared for the Astronomical Journal.
The completed version of the NPM2 Catalog totals 232,062 stars from
all 347 NPM2 fields; it supersedes the September 2002 preliminary
version (295 fields). Together with the NPM1 Catalog (Cat. I/199, or
http://www.ucolick.org/~npm/NPM1/) the NPM2 Catalog completes the Lick
Northern Proper Motion program after more than a half-century of work
by three generations of Lick Observatory astronomers.
The NPM2 catalog gives J2000 positions computed for the catalog epoch
2000, and is ordered in 108 one-degree declination zones from +83
degrees to -23 degrees. Following the convention of the NPM1 catalog,
each NPM2 star has an NPM2 "name" (e.g. +83.0001) reflecting the
declination zone and a running number in right ascension order within
the zone. The NPM2 Catalog is also available as 108 separate files,
one for each declination zone from +83 degrees (z+83n) to -23 degrees
(z-23n), from http://www.ucolick.org/~npm/NPM2/zones/
Each star's entry includes the absolute proper motion and blue (B)
magnitude. For 98.5% of the stars the B-V color is also given. Other
data given for each star are: the original mean epoch, a stellar class
code, the number of NPM fields on which the star was measured, and
discrepancy flags for proper motion, and photometry. Tycho-2 numbers
are given for the primary positional reference stars (40% of NPM2);
for these stars the Tycho B,V photometry, transformed to Johnson B and
B-V, has been averaged with the NPM2 photographic photometry, with
appropriate weights. ACRS and Hipparcos numbers are also given for
NPM2 stars selected from those catalogs.
The RMS precision of the NPM2 individual proper motions is about
0.6"/cent (6mas/yr) in each coordinate, comparable to the NPM1 errors.
The NPM2 relative proper motions in each field were reduced to
absolute (ICRS system) using an average of 370 Tycho-2 stars per NPM2
field. Magnitude-dependent systematic errors for the brightest
(8<B<12) NPM2 stars were removed in the same reductions. The RMS
accuracy of the proper motion zero point in each field is about
0.05"/cent (0.5mas/yr) in each coordinate.
The RMS position errors at the NPM2 catalog epoch 2000 average about
0.2" (200mas) in each coordinate, due mostly to the accumulated proper
motion error from original plate epochs (average 1968) to 2000. The
pure positional errors at the original epochs average 0.08" (80mas) in
each coordinate. The RMS errors for the NPM photographic photometry
average about 0.18mag in B, and 0.20 mag in B-V.
We thank the National Science Foundation for its long-term support of
the NPM program. The NPM2 phase was supported by NSF grants
AST-9530632 and AST-9988105. We thank the Yale Southern Proper Motion
group (W. van Altena, I. Platais, and T. Girard) for their help in
developing software to process the PMM plate scans.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
npm2.dat 115 232062 The NPM2 Catalogue of Absolute Proper Motions
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See also:
http://www.ucolick.org/~npm/NPM2/ : The NPM2 Home Page
I/171 : Astrographic Catalog Reference Stars (ACRS) (Corbin+ 1991)
I/199 : Lick Northern Proper Motion Program: NPM1 Catalog (Klemola+ 1987)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
Byte-by-byte Description of file: npm2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name [0-9.±]! NPM2 star "name" made of:
Byte 1 : Sign of J2000 declination
Bytes 2-3: J2000 Declination zone
Bytes 4-8: Running number in this zone
12- 13 I2 h RAh Right Ascension J2000, Ep=J2000 (hours)
15- 16 I2 min RAm Right Ascension J2000, Ep=J2000 (minutes)
18- 23 F6.3 s RAs Right Ascension J2000, Ep=J2000 (seconds)
26 A1 --- DE- Declination J2000, Ep=J2000 (sign)
27- 28 I2 deg DEd Declination J2000, Ep=J2000 (degrees)
30- 31 I2 arcmin DEm Declination J2000, Ep=J2000 (minutes)
33- 37 F5.2 arcsec DEs Declination J2000, Ep=J2000 (seconds)
38- 45 F8.2 10mas/yr pmRA Absolute proper motion RA (in "/century)
46- 53 F8.2 10mas/yr pmDE Absolute proper motion Dec. (in "/century)
56- 61 F6.2 mag Bmag *B magnitude
62- 67 F6.2 mag B-V *?=-9.99 B-V color
71- 75 F5.2 yr Ep-1900 Original mean epoch of position (-1900)
78 I1 --- Class *[1,7] Code for class of star
81 I1 --- Nfields Number of NPM fields on which
the star was measured
83 I1 --- ips *[0,3] Discrepancy flag Position
84 I1 --- ipm *[0,3] Discrepancy flag Proper Motion
85 I1 --- ibv *[0,3] Discrepancy flag Photometry
88- 99 A12 --- TYCHO Tycho-2 catalog identification
102-107 I6 --- ACRS ACRS (Cat. I/171) catalog identification
110-115 I6 --- HIP Hipparcos (Cat. I/239) catalog identification
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Note on Bmag:
NPM2 photographic photometry unless star has Tycho-2 identification;
then weighted mean of (1) NPM2 magnitude and (2) Tycho-2 blue
magnitude, transformed to Johnson B.
Note on B-V:
NPM2 photographic photometry (-9.99 if no data)
unless star has Tycho-2 identification; then weighted mean of
(1) NPM2 color and (2) Tycho-2 color, transformed to Johnson B-V.
Note on Class:
The code is a sum of the following numbers, if applicable.
+1 if anonymous star (faint or bright)
+2 if astrometric catalog star (Tycho-2, ACRS, or Hipparcos)
+4 if other star (Lick Input Catalog)
Note on ips, ipm and ibv:
Flags for large residuals for stars with multiple measures:
----------------------------------------------------------
Position Proper Motion Photometry
----------------------------------------------------------
Flag=0 O.K. O.K. O.K.
Flag=1 R.A. R.A. Bmag
Flag=2 Dec. Dec. B-V
Flag=3 Both Both Both
----------------------------------------------------------
Limits 0.3arcsec 2.0arcsec/cent 0.5 mag
(at 1968) (20mas/yr)
----------------------------------------------------------
History:
Copied from http://www.ucolick.org/~npm/NPM2/
(End) Robert B. Hanson [UCO/Lick Observatory] 2003-May-23