1 Introduction

In this paper we give new results of a program to identify high proper motion stars in the southern hemisphere, being carried out with the Maksutov Astrograph at the Estación Astronómica de Cerro El Roble (EACR), operated by the University of Chile.

The present survey uses as first epoch plates those taken with the Maksutov telescope between 1969 and 1970 by H. Potter and A. Lokalov. They are centered on 164 fields selected by N. Deutsch on the basis of their high density of galaxies, which were to be used as fiducial objects for the determination of absolute proper motions. Given the characteristics of the telescope, and of the available plate scanning and measuring devices, this original program was conceived with a minimum time base of 20 years.

Subsequent testing showed however that with the available manual measuring machine it was not possible to carry out precise astrometry of the galaxies that had been chosen as reference points, so the absolute proper motion program was momentarily abandoned. On the other hand, as a result of these tests it became clear that a shorter time base, of roughly 15 years, was adequate to determine the relative motions of fast moving objects with respect to background stars, provided that their blue photographic magnitude were fainter than $\sim$ 10 and brighter than $\sim$ 19.

The acquisition of second epoch plates with the latter purpose was therefore started in 1985. As a result of our survey 2055 new high proper motion stars have been discovered in the 99 areas, 25 square degrees each, explored so far (see e.g. [8, Wroblewski & Torres 1997] and references therein). Among these, 89 objects have annual proper motions in the range 0.4-0.5 arcsec/year, 27 in the range 0.6-07 arcsec/year, 3 in the range 0.8-0.9 arcsec/year, and two very rapid moving objects, namely WT248 and WT1827, have motions of 1.197 and 1.971 arcsec/year, respectively. We have also re-discovered 947 stars from the Luyten Catalogue (LTT) within the same areas; for them we have provided improved data and finding charts (see e.g. [9, Wroblewski & Torres 1998] and references therein).

In this work, the sixth part of our program, we present the results of the search for high proper motion stars in other 19, $5^\circ\times 5^\circ$ areas located between $-5^\circ$ and $-30^\circ$ in declination, and 13h 30m and 24h in right ascension. Only newly discovered objects have been included here; new data and finding charts for re-discovered LTT stars will be published elsewhere (Wroblewski & Costa, in preparation).

It should be noted that although up to this point the only specific purpose of our program has been the identification of fast moving stars, once our observational survey is completed a limited statistical analysis of the high proper motion data will be presented, together with an evaluation of the completeness of the Luyten survey. This latter objective is perhaps the most important given some far-reaching conclusions that can be obtained from Luyten's extensive work. In spite of the so far limited sky coverage of our survey, it has proven of importance to studies of the solar neighborhood (see e.g. [6, Patterson et al. 1998]; [4, Henry et al. 1997)].