I/177 Proper motions in NGC 752 (Platais 1992)
Catalogue of proper motions in NGC 752
Platais I.
<Bull. Inf. CDS 40, 5 (1992)>
=1992BICDS..40....5P 1992BICDS..40....5P
=1992yCat.1177....0P 1992yCat.1177....0P
ADC_Keywords: Proper motions ; Cross identifications
Description:
This catalogue was prepared during the study of proper motions
(Platais 1991A&AS...87...69P 1991A&AS...87...69P) in and around the open cluster NGC 752
(C0154+374) which belongs to the poorly-populated open cluster class.
Relative proper motions of 1777 stars have been determined from the
PDS measurements of 11 Pulkovo normal astrograph plates (scale is
59.57"/mm) in a 110'-diameter circle around the cluster. The catalogue
of proper motions is complete down to mpg=15.0m, the limiting value is
15.4m. The average standard error of the catalogue proper motions
varies from 0.75mas/yr (milliarcseconds per year) for stars with
mpg<14.0m to 1.1mas/yr for the rest. These errors refer to the
highest weight group (the star is present on all or nearly all plate
pairs). In order to calculate the standard error of a star belonging
to the lower weight group, it is necessary to use a unit weight error
of 3.7 mas/yr and the appropriate weights from Table I for the plate
pairs used in the determination of the star's proper motion, as given
in the Catalogue. For stars located far from the field centre as well
for fainter stars, an additional factor proportional to the accuracy
degradation should be applied.
Table I. Assigned weights.
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| Pair No.| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---------|-------|-------|-------|-------|-------|-------|-------|
| Weight | 7.0 | 7.0 | 2.5 | 2.3 | 2.8 | 3.0 | 1.0 |
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Example: For the star No. 40 the weighted standard error of the
proper motion is as follows: 3.7/sqrt(2.3+2.8)*1.5=2.5 mas/yr. The
degradation factor of 1.5 comes from the decreased accuracy for the
faint stars located at the edge of the field investigated.
More detailed information on measured plates, standard errors,
assigned weights, membership probabilities etc. is given in Platais
(1991A&AS...87...69P 1991A&AS...87...69P). The membership probabilities were calculated
assuming that on the vector-point diagram the distribution of field
stars is essentially flat within a limited area around the centroid
of the cluster member proper motion distribution. A clear separation
of field and cluster stars is achieved.
Objects:
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RA (2000) DE Designation(s)
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01 57 41 +37 47.1 NGC 752 = Cl Melotte 12
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
main.dat 63 1777 Catalogue of proper motions in NGC 752
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Byte-by-byte Description of file: main.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- No [1/1777] Sequential number of the star.
5- 9 I5 --- NH [1/396]? Identification number from Heinemann
(1926AN....227..193H 1926AN....227..193H).
10- 13 I4 --- NRV [1/497]? Identification number after Rohlfs and
Vanysek (1961AAHam...5..343R 1961AAHam...5..343R) (1)
14- 17 I4 --- NST [1/458]? Number from Stock (1985RMxAA..11..103S 1985RMxAA..11..103S)
list of high accuracy equatorial coordinates.
19- 27 F9.4 mm Xpos [-57/59] Rectangular coordinates along X (2)
28- 36 F9.4 mm Ypos [-56/56] Rectangular coordinates along Y (2)
37- 42 F6.2 mag mpg [6.7/15.4] Photographic magnitude (3)
43- 47 I5 0.1mas/yr pmRA Relative proper motion along right ascension (4)
48- 52 I5 0.1mas/yr pmDE Relative proper motion along declination (4)
53- 55 I3 % Mmb [0/100] Calculated membership probability
in percent.
57- 63 I07 --- PAIRS Designation of plate pairs (5)
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Note (1): In this reference, finding charts and BV photographic photometry
data are available.
Note (2): Rectangular coordinates in millimeters derived from the PDS
measurements of the best first epoch plate (epoch 1903.72; equatorial
coordinates of the optical centre are: 01:54:46.5+37:30:54 (B1950.0)).
The origin of the rectangular X,Y-coordinates and the optical centre
are matched. Also the X,Y-coordinate system is oriented closely with
the equatorial system.
Note (3): Photographic magnitude derived by calibrating with Heinemann's
(1926) photographic magnitudes. An internal accuracy is not worse than
0.05magnitude.
Note (4): Relative proper motions, given in 0.0001"/year. The proper
motions are determined relative to the field stars of about mpg=14.0m.
Note (5): Designation of plate pairs used for the calculation of the
catalogue proper motion. If the star is measured on all pairs this
entry is "1234567", otherwise the omitted pair number is replaced by
a zero (the leftmost digit is a 0 or 1, the rightmost a 0 or 7).
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History:
The catalogue was prepared by Imants Platais and mailed to CDS in
March 1991; the standardized description (this ReadMe) was added in
May 2014.
References:
* Heinemann, K.: 1926, Astron. Nachr. 227, 193 (1926AN....227..193H 1926AN....227..193H)
* Platais, I.: 1991, Astron. Astrophys. Suppl. 87, 69 (1991A&AS...87...69P 1991A&AS...87...69P)
* Rohlfs, K. and Vanysek V.: 1961, Astron. Abh. Hamburg. Sternw. 5, 343.
(1961AAHam...5..343R 1961AAHam...5..343R)
* Stock, J.: 1985, Rev. Mex. Astron. Astrof. 11, 103 (1985RMxAA..11..103S 1985RMxAA..11..103S)
(End) Francois Ochsenbein [CDS] 23-May-2014