II/248 UBV photometry and proper motions in M13 (Kadla, 1966)
An investigation of globular cluster M 13
Kadla Z.I.
<Izv. Glav. Astron. Obs. 181, 93 (1966)>
=1966IzPul.181...93K 1966IzPul.181...93K
ADC_Keywords: Clusters, globular ; Photometry, UBV ; Proper motions
Abstract:
The first epoch plates of 8 globular clusters, available in the plate
collection of the Pulkovo Observatory, were taken with the normal
astrograph at the end of the last and beginning of this century. These
plates had been measured previously by N. Gamalei [1948, IzPul, 141]
in order to determine the proper motions of the clusters. From 40 to
62 stars were used for this purpose and these were assumed to be
cluster members on the basis of their proximity to the cluster
centers. The epoch differences ranged from 30 to 45 years. As this
time interval has now increased considerably (by about a factor of
two), it is planned to redetermine the proper motions of these
clusters, using more precise criteria for the selection of stars
belonging to the cluster. In the previous study (N. Gamalei [1948,
IzPul, 141]) only a limited number of field reference stars were
measured, and as more complete data on the cluster, cluster members
and field stars is desirable all the star images on the plates in an
area 80'x80' will be measured in the present program. For future
studies of the orbits of galactic clusters it is important that the
absolute proper motions be on one system and therefore special
attention should be devoted to this problem.
The present paper is a continuation of an investigation of M13 and
deals with the determination of the proper motions and U, B, V
magnitudes of separate stars and also a redetermination of the proper
motions of the cluster.
The U, B, V magnitudes of the majority of 923 stars with measured
proper motions were found from plates (table 2) taken with the 2 meter
Schmidt telescope at Tautenburg and kindly lent to us by Professor N.
Richter. The photoelectric standards as given by Savedoff
[1956AJ.....61..254S 1956AJ.....61..254S] (table 7) and also U B V magnitudes of six
bright field stars (table 8) observed by Mayer were used for
calibration. A comparison of the determined B and V magnitudes of
stars within an area of about 10'x10' centered on the cluster with
those obtained by other authors indicates that the probable external
errors do not exceed ±0.03mag (table 15). However as the
photoelectric magnitudes of fainter field stars were not available, a
slight systematic error may be present in the derived magnitudes of
these stars.
Data on the plates used for the determination of the proper motions
were given in Kadla [1963AZh....40..691K 1963AZh....40..691K]. The relative proper motion
of M 13, redetermined on the basis of a larger number of cluster
members (80 in all, measured on 4 pairs of plates with a mean epoch
difference equal to 61.4 years) is found to be µx=+0.0008",
µy=-0.0014" with a probable error of ±0.0002".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 77 923 M 13 UBV photometry and proper motions
table8.dat 42 6 New photoelectric photometry
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See also:
IV/26 : Hercules Messier 13 (M13) photometry (Ludendorff, 1905)
J/AJ/122/3219 : M3 and M13 CCD BV photometry (Rey+, 2001)
Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- KAD Sequential number, Cl* NGC 6205 KAD NNN
5- 12 F8.4 arcmin Xpos X position (G1)
15- 22 F8.4 arcmin Ypos Y position (G1)
24- 28 F5.2 mag Vmag V magnitude
31- 35 F5.2 mag B-V B-V colour index
38- 42 F5.2 mag U-B U-B colour index
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- KAD [1/923]+ Sequential number,
Cl* NGC 6205 KAD NNN in Simbad
4 A1 --- --- [,]
6- 9 I4 --- Lud ? Number of Ludendorff (1905, Cat. <IV/26),
NGC 6205 NNNN in Simbad
11- 18 F8.4 arcmin Xpos X position (G1)
20- 27 F8.4 arcmin Ypos Y position (G1)
29- 33 F5.2 mag Vmag ? V magnitude
35- 39 F5.2 mag B-V ? B-V colour index
41- 45 F5.2 mag U-B ? U-B colour index
47 I1 --- o_Vmag [1-4]? Number of photometric observations
50- 54 I5 0.1mas/yr pmx Proper motion along x axis
56- 60 I5 0.1mas/yr pmy Proper motion along y axis
62 I1 --- o_pmx [1-4] Number of measurements for proper
motion
64 I1 --- Class [1-3]? Membership probability flag (1)
66- 76 A11 --- BD BD (Bonner Durchmusterung) number
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Note (1): Membership probability flag is defined as follows:
1 = the star is probably a cluster member
2 = the probably is lower but that the star still has a reasonable
chance of being a member
3 = the star is very probably not a cluster member
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Global notes:
Note (G1): Plate centered at RA = 16 39 57.00 (1950) DE = +36 34 13.0
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History:
* 27-Jun-2005: Prepared via OCR at CDS.
* 20-Nov-2017: units of proper motions corrected
(End) Patricia Bauer [CDS] 17-Jul-2003