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VI/25 POSS Plate Data (Palomar Obs. 1960)
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National Geographic Society and Palomar Observatory Sky Survey Catalogue of
Plates
Palomar Observatory
<National Geographic Society (1960)>
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ADC_Keywords: Surveys ; Plate data
Description:
This catalog contains plate-center and observational data for all plates
of the National Geographic Society and Palomar Observatory Sky Survey
(POSS) and its Whiteoak Extension. The POSS proper consists of
photographic reproductions of red-sensitive (Kodak 103a-E) and
blue-sensitive (Kodak 103a-O) plates taken of 937 different fields with
the 48-inch Palomar Schmidt telescope, covering the entire sky above -33
degrees declination. This southern limit was extended to about -45
degrees by J. B. Whiteoak using the same instrument for a series of 100
photographs that have come to be known as the Whiteoak Extension; thus,
the survey as a whole includes 1037 fields. This version of the
catalogue consists of plate information reproduced from the Catalogue of
Plates and plate information on the Whiteoak Extension derived from
file headers of the SAOPSS II tape (Lund and Dixon 1973). The fields of
the catalog are POSS number, modified Luyten-Palomar (MLP) number,
equatorial coordinates of the plate center (B1950), limits of the right
ascension on the plate in radians, galactic coordinate of the plate
center, number of SAO stars on the plate, observing dates and times, the
hour angles for the observations, length of exposure, and seeing rating.
The following basic quantities were taken directly from the Catalogue of
Plates: POSS number, exposure dates and times, hour angles, seeing
ratings, and coordinates in sexagesimal units. The following derived
quantities were calculated at the ADC: MLP number, equatorial
coordinates in radians, right ascension limits, galactic coordinates,
and number of SAO stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
nposs.dat 150 1037 Catalog Data
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Byte-by-byte Description of file: nposs.dat
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Bytes Format Units Label Explanations
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1- 4 4A1 --- ID *Palomar Observatory Sky Survey (POSS) number
6- 9 I4 --- MLP *Modified Luyten Palomar (MLP) number
10- 20 F11.8 rad RArad Equatorial coordinates (1950) of plate center
21- 31 F11.8 rad DErad Equatorial coordinates (1950) of plate center
33- 43 F11.8 rad minRArad *? Minimum right ascension, R.A.(min) (1950)
44- 54 F11.8 rad maxRArad ? Maximum right ascension, R.A.(max) (1950)
56- 61 F6.2 deg GLON Galactic longitude (lII) of plate center
62- 67 F6.2 deg GLAT Galactic latitude (bII) of plate center
69- 71 I3 --- SAO *Number of SAO stars on the plate
73- 76 I4 --- YEAR *Year of the observing night
78- 80 3A1 --- iMONTH Initial Month of observing night
82- 83 I2 --- iDAY Day on which the observing night began
85- 87 3A1 --- fMONTH Final Month (JAN - DEC) of observing night
89- 90 I2 --- fDAY Day on which the observing night ended
92- 93 I2 h EiTIMEh *? Start time of the red plate, hours
95- 96 I2 min EiTIMEm ? Start time of the red plate, minutes
98- 99 I2 h OiTIMEh ? Start time. of the blue plate, hours
101-102 I2 min OiTIMEm ? Start time of the blue plate, minutes
104-105 I2 h EiHAh *Starting hour angle of the red plate, hours
107-108 I2 min EiHAm Starting hour angle of the red plate, minutes
110 A1 --- EiHAew [EW]Direction of the hour angle, East or West
112-113 I2 h OiHAh ? Starting hour angle of blue plate, hours
115-116 I2 min OiHAm ? Starting hour angle of blue plate, minutes
118 A1 --- OiHAew [EW]Direction of the hour angle, East or West
120-121 I2 min Eexp Length of exposure for the red (E) plate
123-124 I2 min Oexp *? Length of exposure for the blue (O) plate
126-128 3A1 --- Erate *? Seeing rating of the red (E) plate
130-132 3A1 --- Orate *? Seeing rating of the blue (O) plate
134-135 I2 h RAh Hours of right ascension, 1950 plate center
137-138 I2 min RAm Minutes of right ascension
140-141 I2 s RAs Seconds of right ascension
142 A1 --- DE- Sign of declination, 1950 plate center
143-144 I2 deg DEd Degrees of declination
146-147 I2 arcmin DEm Minutes of declination
149-150 I2 arcsec DEs Seconds of declination
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Note on ID:
Palomar Observatory Sky Survey (POSS) number. This is
the plate number of the red (E) plate as listed in the
Catalogue of Plates. This machine-readable version
is ordered by declination zones decreasing by roughly
6-degree decrements from +90 to -42 degrees. Within
declination zones, the catalogue is ordered by
increasing right ascension.
The right ascension given for the two polar plates, POSS
570 and 567, describes the orientation of the plates on
the sky. When the plates are oriented so that the plate
label is in the top left corner, the right ascension
describes the line from the plate center to the middle
of the bottom edge.
The POSS numbers for the plates covering the declination
zone of -30 degrees contain an `S' in byte 1; the `S'
must be included because some of the same plate numbers
are used elsewhere in the catalogue. Records 938 to
1037 of the catalogue contain the plate information for
the "Whiteoak extension." Only red-sensitive plates were
taken in the extension, so certain data fields
concerning the blue (O) plates are left blank. See also
Section 4 below.
Note on MLP:
Modified Luyten Palomar (MLP) number. The MLP number is
from 1 to 1037 when the catalogue is sorted by
an integer quantity defined to increase sequentially
declination zone in the manner described above;
therefore, the MLP number can be used as a record number
for the sorted catalogue.
Note on minRArad:
Limits of the right ascension on the plate, in radians.
The limits were computed by solving the corner equation
for each plate (Nagy 1980, Lund and Dixon 1973). The
right ascension of the plate center, R.A.(center), the
minimum right ascension, R.A.(min) and the maximum right
ascension, R.A.(max), are such that R.A(min) <
R.A.(center) < R.A.(max). This means that if
R.A.(center) is near 0.0 radians, R.A.(min) can be
negative, and if R.A.(center) is near 2 pi radians
R.A.(max) can be greater than 2 pi.
Note on SAO:
Number of SAO stars on the plate. This number is taken
from the output multifile tape of the Palomar
Plate Assignment (PPA) program described by Nagy (1980).
Note on YEAR:
The observing date for the exposure, expressed as the
two dates spanned by the observing night; for example,
January 31 - February 1 for overnight starting January
31. The actual calendar date of the start of an
exposure must be inferred from whether the start time
(bytes 101-111) is just before or just after midnight.
In all cases, the red and blue plates were taken in
succession to allow a comparison as free as possible from
variations.
Note on EiTIMEh:
Exposure start times in Pacific Standard Time for both
the red (E) and blue (O) plates. For the Whiteoak
extension (MLP numbers 938 through 1037) bytes 92-102
are left blank.
Note on EiHAh:
Hour angles at the start of exposure for both the red
(E) and blue (O) plates.
Each exposure in the Whiteoak extension (MLP numbers 938
through 1037) was started on the meridian to maximize
the quality of the plate at such low declinations (see
Lund and Dixon 1973 for further details concerning the
exposure techniques). Hence, the last 100 records of the
catalogue list give the starting hour angle of the red
plate as zero. The fields for the blue plate are blank
in these fields, as only red plates were taken in the
Whiteoak extension.
Note on Oexp:
For the Whiteoak extension, MLP numbers 938 through
1037, this field is blank.
Note on Erate:
Seeing rating of the red (E) plate on a scale of one to
five. For the Whiteoak extension, MLP numbers 938 through
1037, this field is blank.
Note on Orate:
Seeing rating of the blue (O) plate on a scale of one
to five. For the Whiteoak extension, MLP numbers 938
through 1037, this field is blank.
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References:
Lund J., and Dixon R. 1973, PASP, 85, 230
Nagy T.A., 1980, ADC Bull., 1, 28
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(End) Julie Anne Watko [SSDOO/ADC] 12-DEC-1995