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I/153 Lick Saturn-Voyager Reference Star Catalogue (Klemola+, 1979)
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Lick Saturn-Voyager Reference Star Catalogue
Klemola A.R., Taraji H., Ocampo A.
<Lick Observatory, University of California, Santa Cruz (1979)>
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ADC_Keywords: Positional data; Regional catalog
Abstract:
The Lick Saturn-Voyager Reference Star Catalogue contains accurate
equatorial coordinates for 4551 stars in a band of sky against which
cameras of the Voyager spacecraft were pointed for observations in the
region of Saturn during the flyby. All of the reference stars are in
the range 12h 40min to 14h 12min in right ascension (1950) and +02deg.
to -09deg. in declination. Mean errors of the positions are about
0.25".
Introduction:
The Lick Saturn-Voyager Reference Star Catalogue was prepared for
purposes of determining up-to-date, reasonably accurate, equatorial
coordinates for reference stars in a band of sky against which cameras
of the Voyager spacecraft were aligned for observations in the region
of Saturn during the flyby. The requirements were a surface density of
about three reference stars per observation frame of 24 sq.arcmin of
the cameras - somewhat greater that the SAO (Smithsonian Astrophsyical
Observatory Staff 1966) and the AGK3 (Dieckvoss et al. 1975) densities
- and a positional accuracy +/- 0.5". Visual magnitudes were also
required. The completed catalog contains 4551 stars in the right
ascension range 12h 40min to 14h 12min, declination zones +02deg. to
-09deg. Mean errors of the positions, as derived from least squares
solutions against the Perth 70 Catalogue (Hoeg and von der Heide
1976), are about 0.25"; however, individual residuals for some bright
and excessively faint stars are as high as 0.5" to 1.0". The
accidental error of one measurement, as deduced from a tabular
histogram given in the original catalog publication (referenced
below), is about 0.09".
Apparent photographic and visual magnitudes were derived from iris
photometer measurements, visual magnitude being approximated from a
derived color-index relation using UBV stars selected from the USNO
photoelectric catalog (Blanco et al. 1968) and extended with Perth 70
stars. The resulting magnitudes appear to have mean errors of at least
0.2mag - 0.3mag for the brighter stars (visual magnitude < 10mag) and
uncertainties can be as much as 0.5mag for the fainter stars. The
magnitudes are considered to be only approximate, especially on the
faint end, because of a lack of photoelectric standards there.
For additional information concerning the observations and reductions,
the original publication (available from A. R. Klemola) should be
consulted.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 56 4551 *The catalog
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Note on catalog.dat:
Certain fields contain character data and others are blank when data
are absent. Particular care is necessary with the proper-motion data,
where missing data will be read as zeros, but where valid zero values
may exist.
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See also:
I/152 : Lick Jupiter-Voyager Reference Star Catalogue (Klemola+ 1978)
I/125 : Combined Lick-Voyager Reference Star Catalogue (Dunham 1986)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Labels Explanations
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1- 4 I4 --- num Running star number
5- 8 I4 --- pl_num Plate number
9- 10 I2 h RAh *Right ascension, hours (Eq=1950, Ep=1978.92)
11- 12 I2 min RAm *Right ascension, minutes (1950)
13- 18 F6.3 s RAs *Right ascension, seconds (1950)
19 A1 --- DE- *Sign of declination zone
20- 21 I2 deg DEd *Declination degrees (1950)
22- 23 I2 arcmin DEm *Declination arcminutes (1950)
24- 28 F5.2 arcsec DEs *Declination arcseconds (1950)
29- 33 F5.2 mag Pmag *?Photographic magnitude (1950)
34- 38 F5.2 mag Vmag *Visual magnitude
39- 46 A8 --- Name *Alternate identification
47- 51 F5.1 10mas/a pmRA *?Proper motion in right ascension
52- 56 F5.1 10mas/a pmDE *?Proper motion in declination
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Note on RAh, RAm, RAs, DE-, DEd, DEm, DEs:
Equinox=1950, Epoch=1978.92.
Note on Pmag:
Determined from iris photometry.
Note on Vmag:
Apparent visual magnitude, m(v), approximated from visual magnitude
and a derived color-index relation using UBV stars selected from the
USNO photoelectric catalog of Blanco et al. (1968) and extended with
Perth 70 stars.
Note on Name:
AGK3 or SAO identification number. For AGK3 numbers, bytes 39-41
contain the zone and bytes 42-46 the number. SAO numbers are
contained in bytes 41-46.
Note on pmRA and pmDE:
These data are taken from the AGK3 or SAO catalogs. The proper
motions in right ascension are given as the great circle measures.
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History:
A magnetic tape containing the catalog, in binary format, was received
from Dr. A. R. Klemola in November 1981. The data were converted to
character-coded form and written to a direct access storage device for
editing. The following modifications were made to the data in order to
effect a more uniform format and to standardize the data representation:
Plus signs were added to all positive declination zones.
Missing data were converted from zeros to blanks. Since there are valid
zero proper-motion data in the catalog, the source reference had
to be scanned visually to locate all these values so that they
could be converted back to zeros again. In the original
machine-readable file, there was no way to tell between zero
proper motions and missing values.
All AGK3 numbers were converted to the representation +/-XX XXXX (SAO
numbers were not modified).
The catalog was sorted by increasing right ascension (the stars were
originally in some kind of plate or measurements order).
A copy of the catalog, originally archived and documented at the ADC in
1982, was sent to W. M. Owen, Jr. of the NASA Jet Propulsion Laboratory,
in January 1990. Mr. Owen, having collaborated with Dr. Klemola in the
preparation of the Lick Reference catalogs for the Uranus and Neptune
encounters, reviewed the catalog and made the following modifications to
the file:
AGK3 designations and proper motions were added for 17 stars not
previously identified as AGK3 stars.
SAO numbers and proper motions were added for eight stars not previously
identified as SAO stars.
Four stars appeared in the catalog twice. Their positions and magnitudes
were averaged and the duplicate entries deleted.
Stars 575/8718 and 219/8718 were incorrectly identified as SAO stars;
their identification and proper-motion fields were blanked out.
Three AGK3 and six SAO designations were erroneous and were corrected.
(The proper motions were found to be correct for these entries,
however.)
Acknowledgments:
Appreciation is expressed to A. R. Klemola for providing the magnetic
tape of the catalog and for reviewing the modifications made to the
data. Dr. Klemola also kindly reviewed a draft copy of this document
before its completion and printing. The work of W. M. (Bill) Owen, Jr.,
in correcting and updating the earlier version of the catalog, is
gratefully acknowledged, as are his comments on the statistical accuracy
of the positions and the revised documentation.
This document was written by Wayne H. Warren Jr. and was translated from
a Script version to the current standard ASCII form.
References:
Blanco, V. M., Demers, S., Douglass, G. G., and FitzGerald, M. P. 1968,
Publ. U. S. Naval Obs., 2nd Ser., 21.
Dieckvoss, W., Kox, H., Guenther, A., and Brosterhus, E. 1975, AGK3.
Star catalogue of positions and proper motions north of -2.5 deg.
declination, derived from plates taken at Bergedorf and Bonn in the
years 1928-1932 and 1956-1963, Hamburger Sternwarte,
Hamburg-Bergedorf.
Hoeg, E. and von der Heide, J. 1976, Perth 70, A Catalogue of Positions
of 24900 Stars, Abh. der Hamburger Sternwarte, Band IX.
(Catalog <I/62>)
Klemola, A. R. (Lick Obs.), Taraji, H., and Ocampo, A. (Jet Propulsion
Lab.) 1979, Lick Saturn-Voyager Reference Star Catalogue, Lick
Observatory, University of California, Santa Cruz.
Smithsonian Astrophysical Observatory Staff 1966, Star Catalog.
Positions and Proper Motions of 258,997 Stars for the Epoch and
Equinox of 1950.0, Publ. of the Smithsonian Institution of
Washington, DC No. 4652 (Washington: Smithsonian Institution).
(See cat. <I/131>)
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(End) Nancy G. Roman [ADC/SSDOO] 02-May-1995