The Karl-Schwarzschild-Observatorium, about 15 km away from Jena in the Tautenburg forest at 330 m above sea level, was founded in 1960. The 2m-Universal-Telescope contains three optical systems: Schmidt, Cassegrain and Coudé. The spherical primary mirror consists of Sitall (a Russian ceramic glass).

The Sonneberg collection numbers about 250,000 photographic plates; those of the Sonneberg Sky Patrol and Field Patrol reach back into the past as far as 1926. The Sky Patrol aims at providing a continuous record of the whole northern sky; the Field Patrol, of 81 fields selected along or near the Milky Way.

The 2m Ritchey-Chrétien-Coudé (RCC) telescope of the National Astronomical Observatory, situated in the Rozhen massif of the Rhodope Mountains, started operating in 1980 (for a detailed description of the telescope see Gutcke [1979]). Since then, 2000 direct photographs have been obtained, most of them covering a 1° × 1° area on the sky with resolution 12.9 sec/mm.

We present the results from the analysis of the machine-readable version of the log book for the 50/70 cm Schmidt telescope of the National Astronomical Observatory (NAO) Rozhen of the Bulgarian Academy of Sciences. The telescope began operating in 1979, after it was repaired and transferred from the Potsdam Observatory where it had operated since 1952.

The important role of flare stars (UV Ceti type variables) in astrophysics is due to the fact that the flare activity is not only typical for red stars with small masses but is a necessary stage during their evolution. The flare star search in stellar aggregates has led to the accumulation of rich observational material allowing us to look for statistical regularities in star formation and evolution. At present, there are more than 1500 known flare stars in the Galaxy; these were discovered mainly during the last 30 years. Most results of the long term monitoring with wide-field telescopes are listed in existing catalogues of flare stars in stellar aggregates and in the solar neighbourhood. These catalogues and their machine-readable versions were the basis for the present database of flare stars in the Galaxy.

Past surveys are described in the logical sequence of (1) comets visually, (2) asteroids visually, (3) asteroids photographically and (4) comets photographically. Plots show the evolution of asteroid surveys in terms of visual discovery magnitude and ecliptic latitude, and similarities and differences between surveys for the different types of body are discussed. The paper ends with a brief discussion of more recent discovery methods and some thoughts on the future.

While the accuracy of photometric star counts rises, constraints on the stellar population characteristics improve and allow synthetic models to be conceived to explain the galactic structure. We show here how star counts have significantly contributed to build a comprehensive picture of galactic evolution and dynamics.

A 270 square degree survey for Very Low Mass (VLM — M < 0.2M⊙) stars in the field is discussed. The major pitfalls encountered in the survey are covered, as well as the major results. In particular, it was found that: 1) no significant difference is seen between the luminosity function for VLM stars as measured by photometric and trigonometric selection criteria; 2) the luminosity function does not show a significant increase below Mbol = 13, 3) the mass function for VLM stars shows significant structure in the VLM regime; and 4) it is hard to envisage a significant amount of missing mass in the disk being in the form of brown dwarfs.

We test a model of stellar evolution synthesis by comparison with (V, B–V) counts at the pole. The history of the stellar birthrate and dynamical evolution in the disc is explicitly taken into account. The data span a large range of magnitudes from V = 7 to 22, and allow us to put new constraints on the evolution of the galactic disc.

The spatial distribution of metal abundance in the Galaxy has been analyzed using the UBV starcount data recently obtained in two high-latitude regions of the North Galactic Pole (NGP) and Selected Area 54 (SA54).

A least-squares analysis was performed to determine the vertical metallicity gradient for each of the thin and thick disk components that gives a reasonable fit to the observed U-B and B-V colour distributions to V = 18 mag. The most probable value of the vertical gradient is obtained as d[Fe/H]/dz = −0.5 kpc−1 for the thin disk, and −0.1 kpc−1 for the thick disk.

Starcounts remain one of the most effective methods of probing the structure of the Galactic stellar populations. However, studies of the distribution at large distances above the Plane demand accurate photometry extending to faint magnitudes (V > 20), and such datasets are still rare. We (Reid & Majewski 1993) have analyzed data from one field — Majewski's (1992) UJF observations of SA57, the North Galactic Pole field. Our results revealed significant discrepancies with the standard model of the Galaxy (see refs. in Reid & Majewski), notably a paucity in the number of halo stars by a factor of two and the presence of a factor of two more disk stars than predicted — sufficient stars that the disk is the majority stellar population, outnumbering halo stars 2:1 even at V = 21. Majewski et al. (1993) has obtained UJFN photographic data for several other fields, and Fig. 1 shows a preliminary comparison of these observations with the predictions of the best-fitting SA57 model. Given that none of the parameters have been modified, the agreement is surprisingly good.

The application of astrometric surveys to understanding the structure and kinematics of the Milky Way is discussed, with particular emphasis on some of the issues expected to be addressed in the next decade or so. It is shown that the results of complete proper motion surveys of field stars at the Galactic poles are in remarkable agreement concerning the global kinematics of stars as a function of distance, but that significant differences exist in how these data are decomposed to derive the kinematics of individual Galactic components. The status and future prospects regarding the measurement of proper motions and orbits for Galactic globular clusters and satellites are also discussed.

A sample including 2370 stars with (U, V) velocities has been analyzed up to z = 2.5 kpc. It is shown that the observed vertical gradient in the velocity distribution can be explained by the sum of 3 discrete populations with constant kinematics. The observations are well fitted by exponential density laws for the thin disk and the thick disk with scale lengths of 280 pc and 700 pc respectively, and with local densities of 6% and 0.15% for the thick disk and halo respectively.

For a detailed investigation of the kinematics of our Galaxy we need accurate proper motions and photometric data of stars over a wide range of magnitudes. The proper motions have to be obtained with respect to an extragalactic, i.e. nonrotating reference system. The best way to determine absolute proper motions of a great number of stars for further statistical analysis is to use the enormous amount of information stored on photographic plates taken with large Schmidt telescopes within the last decades. Since automated measuring machines have become available it is no longer a problem to extract this information from a Schmidt plate. Large Schmidt plates cover a sky area of more than 30 square degrees with usually thousands of stars and hundreds of galaxies per square degree outside the galactic plane. With the Tautenburg Schmidt telescope (134/200/400) more than 8000 plates have been taken in selected Northern sky areas since it was mounted in 1960. A 24 cm × 24 cm Tautenburg plate covers a field of about 10 square degrees, and a 20 minute exposure of a B plate has a limiting magnitude of 19 to 21. In comparison to other large Schmidt telescopes the plate bending is reduced to a minimum due to the four metre focal length and the use of relatively small plates. Therefore irregular positional shifts of the emulsion caused by the rebending after the exposure are of less influence. The large focal length leads to a plate scale of 51 arcsec/mm providing a relatively high positional accuracy.

The spatial velocity components and their dispersions in the Galactocentric and rotation directions, eccentricities of Galactic orbits, parameters of spatial distribution and the change of all these characteristics with distance from the Galactic plane are detennined. These data have been obtained on the basis of absolute proper motions and stellar B, V magnitudes in two sky regions near the North Galactic Pole (NGP) by means of a plate set of the Tautenburg Schmidt telescope.

We present the observational results of UBV photometry and absolute proper motions in the anticentre direction at intermediate latitude (l = 167.5°, b = 47.4°) for an 8.6 square degree field. The sample is complete down to V = 17, and the accuracy of the proper motions is better than per century for stars brighter than V = 16. It is attempted here to make an investigation of the structure and kinematics of the Galaxy from absolute proper motions. Details of the present work can be found elsewhere (Ojha et al. 1993).

As a first step in our open cluster programme, a preliminary catalogue of proper motions and photographic B, V magnitudes for stars up to 18 mag within a region centred near Alcyone is presented. The catalogue is based on MAMA measurements of plates taken with the Tautenburg Schmidt telescope. A preliminary survey includes approx. 20,000 stars and covers a total field of about 9 square degrees. For stars brighter than B = 18 mag an accuracy of 0.05 mag and 2.5 mas/year has been estimated for photometric data and proper motions, respectively. The results of the determination of the Pleiades membership up to magnitude 18 are presented

We present results from orbit integrations for the globular clusters M 3 and M 92. Absolute proper motions recently measured from Tautenburg Schmidt plates and a three-component mass model for the Galaxy have been used to derive the galactic orbits of these clusters. Orbital parameters and the influence of observational uncertainties on the determination of the orbits are discussed.

A proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M 3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). With a limiting magnitude of B = 21, proper motions of 2 to 3 mas/yr accuracy have been obtained for stars with B < 19. The proper motions were determined applying a stepwise regression method with 3rd order polynomials in the plate-to-plate solutions with about 2000 reference galaxies. We used the results for the determination of membership probabilities and looked for internal motions of M 3.

Space motions of globular clusters are important for the understanding of the kinematics and chemical evolution of the Milky Way. The greatest problem for the determination of the space motions of the globular clusters arises from the difficulties of getting absolute proper motions. In the past these were determined using classical stellar reference frames, modelling of the non-cluster stars in the field and extragalactic objects in the region of the cluster (see e.g. Cudworth & Hanson 1993; Geffert et al. 1993 for references). However, as shown for M 15 and M 3 (Geffert et al. 1993; Tucholke et al. 1993), the results based on different methods for deriving the absolute proper motions differ by up to yrs. In order to get a more complete view of the differences between the various methods it is therefore very interesting to get absolute proper motions based on all three methods for further objects. We present here the first results of a new proper motion study of the globular cluster M 2.