Proper motions with an 80 year baseline have been determined relative to reference stars with B=13.9mag. determined for 3086 stars brighter than B=15.5mag. within an area of 50' radius, centered at RA=2h16.9m, Dec=+57{deg}01' (1950.0). Two pairs of Tashkent normal astrograph plates with a mean epoch difference of 80 years was used. Proper motions were also measured for 1055 stars with 15.5 <= B <= 17.1 mag. in two areas 14' in radius, centered on the h and {chi} Persei clusters. Proper motions are also given for 1386 stars in an adjacent area (RA=2h06.7m, Dec=+56{deg}57') for 1386 stars with a 38 year baseline. The mean errors of the proper motions are equal in right ascension and declination. For the h and {chi} Perseus region, they are 0.0021"/yr and for the adjacent region, they are 0.0031"/yr. The proper motions in the adjacent area have been reduced to the system of those in the cluster region using 214 stars in common. UBV magnitudes of the stars were determined using plates taken with the 80/120/240 Schmidt telescope of the Radioastrophysical Observatory of the Academy of Sciences of the Latvian SSR and photoelectric standards published by Johnson and Morgan (1955ApJ...122..429J) and Widley (1964ApJS....8..439W). The number of measured plates and the corresponding errors are given in the following table: ----------------------------------------------------- FILE NAME # PLATES ERRORS (0.01mag) V B U V B U ----------------------------------------------------- data1.dat 2 3 2 6 5 6 data2.dat 1 2 - 8 6 - adjarea.dat 2 2 2 6 6 6 _____________________________________________________ Cluster members were selected on the basis of their proper motion and photometric criteria. The membership probability was calculated on the assumption of a normal distribution of the proper motions around the cluster proper motion.
Relative proper motions of 872 stars in the open cluster M 11 region are reduced using 10 plate pairs taken over time baselines of 16~70 years with the double astrograph telescope of Shanghai Observatory. The scale is 30"/mm. The plates were measured with the PDS machines in the Purple Mountain Observatory in Nanjing and the Institute of Technology and Communication in Luoyang, China. The average proper motion accuracy is about 1.1mas/yr with 85% of the data better than 1mas/yr. Membership probabilities of 785 stars within 25' centred on M 11 are determined based on their proper motions. The method used is suggested by Su et al. (1995AcApS..15..217S) with some improvements of Zhao & He (1990A&A...237...54Z), in which the space distribution and magnitude dependencies for cluster stars are taken into account. The results are significantly good. The total integrated membership probabilities for all these stars is 547 and the number of stars with probabilities higher than 0.7 is 541. It can be found after the membership determination that there exists mass segregation in M 11. Some comparisons and discussion are also given.
Relative proper motions and membership probabilities of 1046 stars in the open cluster M67 are are determined from PDS measurements of 9 plate pairs taken with the double astrograph at the Zo-Se station Shanghai Observatory, which has an aperture of 40cm, a focal length of 6.9m and a scale of 30"/mm. The number of stars with membership probabilities higher than 0.8 and at a distance less than 45' from the field center is 282. The average standard errors of proper motions vary from +/-0.0004"/yr for bright stars in the inner part of the field to some +/-0.0015"/yr for faint stars in the outer part of the cluster. It is shown by a detailed discussion that the proper motions and membership probabilities of the stars determined in this paper are in quite satisfactory agreement wit those obtained by Sanders (1977A&AS...27...89S) or Girard et al. (1989AJ.....98..227G).
The astrometric accuracy of triple image Carte du Ciel plates has been analysed using plates of the open cluster NGC 1647. A new multithreshold technique was used for the treatment of the triple image plates. Accuracies ranging from 100mas to 200mas were found. We determined proper motions with a median accuracy of 1.6mas/a for 2220 stars in the field of NGC 1647. The membership probabilities of stars in the cluster region agree very well with the data of Francic (1989). Due to a significant difference of the proper motions of SZ Tau and the cluster members, SZ Tau seems not to be a member of NGC 1647.
From photographic plate data of Shanghai Astronomical Observatory with a time baseline of 87 years, proper motions and membership probabilities of 364 stars in the open cluster NGC 6530 region are reduced. On the basis of membership determination, luminosity function and segregation effect of the cluster are discussed with details. Spatial mass segregation is obviously present in NGC 6530 while there is no clear evidence for a velocity-mass (or velocity-luminosity) dependence. The observed spatial mass segregation for NGC 6530 might be due to a combination of initial conditions and relaxation process.
The results of astrometric and photometric investigations of the open cluster NGC 7243 are presented. Proper motions of 2165 stars with root-mean-square error of 1.1mas/yr were obtained by means of PDS scanning of astrometric plates covering the time interval of 97 years. A total of 211 cluster members down to V=15.5mag have been identified. V and B magnitudes have been determined for 2118 and 2110 stars respectively. Estimations of mass 348M_{sun}_<M<522M_{sun}_, age t=2.510^8^yr, distance r=698pc and reddening E(B-V)=0.24 of the cluster NGC 7243 have been made.
We derive the proper motions, membership probabilities, and velocity dispersions of stars in the regions of the young (~2-4Myr old) open clusters NGC 2244 (the central cluster in the Monoceros R2 association) and NGC 6530 (the dominant cluster in the Sgr OB1 association) from photographic plate material obtained at Shanghai Astronomical Observatory, with time baselines of 34 and 87yr, respectively. Both clusters show clear evidence of mass segregation, but they do not exhibit any significant velocity-mass (or, equivalently, velocity-luminosity) dependence.
The plates of wide-field astrograph are used to measure the proper motions of 1065 stars in 1.8x1.8 deg. field of the open cluster NGC 7063. The magnitude equation is analysed, and the cluster members are identified.
High-precision proper motions for 257 and 296 stars in a 90'x90' region centered on BD+20 2170 were obtained from seven plates taken with the Zo-se 40cm refractor (f=6895mm) in March, 1986 (see the "Plate Summary" section below), combined with six AC plates and the stellar positions in Russell's (1976, Ph.D. Thesis, Pittsburgh University). Combined with other data, membership probabilities were estimated by an improved maximum likelihood method. A very good sample of 198 members is obtained with proper motion accuracies ranging from +/-0.2 to +/-5.0mas/yr, of which 60% are better than +/-1.0mas/yr; the completeness limit is about B=15.5mag. Note that the table published in electronic form associated to the paper published in 1995A&AS..113..419W presented positions not correctly associated to the stars (see the "History" section below)
