Parallaxes and proper motions. XVII.

Parallaxes and proper motions are presented for 23 stars in 19 star fields. Seven of the target stars and one other star have no previous parallax determinations. New photometry is also presented for two of the stars for which previous data had not been published. Two of the target stars are resolved binaries for which both components were measured separately; one of the two is not a physical pair. This list is the first in the series which makes use of the PDS microdensitometer of the Yale Observatory with five of the 19 star fields being measured there. The PDS measures are too few for a reliable direct comparison with the hand measures, but they appear to be more accurate. This is also the first list to report parallaxes of subdwarf candidates. Subluminous stars now form a second commitment of the program along with the K and M dwarfs which have formerly dominated the program.