COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 2905

                                                       Konkoly Observatory
                                                       Budapest
                                                       6 June 1986

                                                       HU ISSN 0374 - 0676


 THE PROPER MOTION OF VX Sgr DERIVED FROM LIBRARY MATERIAL

An approximate value of the proper motion of this star has
been derived by Soulie and Baudry (1983) (mu alpha*cos delta=-0.008"/yr,
mu delta=+0.003"/yr) using as a first-epoch position the one quoted
in the GCVS which is not the best source for the astrometric
position of any variable star. In order to get a more reliable
first-epoch position, I have rereduced plate 1821 of the
Hyderabad southern part of the Astrographic Catalogue (A.C.)
(epoch 1921.75) where VX Sgr was identified with object 60855.
The reference stars were taken from the SAOC which gives a
mean error of +-0.36" in alpha and +-0.33" in delta.

The second epoch position has been taken from Soluie and
Baudry's paper in which the epoch of observation is 1979.75
and a mean error of +-0.15" in alpha and +-0.20" in delta. has been
assumed (see Soulie and Baudry, 1983).
I have declined to use plate 2077 of the Hyderabad A.C. in
which VX Sgr (object 68680) lies near the edge of the plate.
With the available material the following annual proper
motion, in the system of the SAOC, is derived:

mu alpha*cos delta = +0.010" +-0.007" (me);   mu delta = +0.022" +-0.007" (me)


                            CARLOS E. LOPEZ
                       Observatorio "Felix Aguilar"
                         Benavidez 8175 (oeste)
                        5413 Chimbas - San Juan
                              Argentina



Reference:

Soulie, G., Baudry, A.: 1983, Astron.Astrophys. Suppl. Ser. 52, 299. [BIBCODE 1983A&AS...52..299S ]