This paper reviews the Lick Northern Proper Motion (NPM) program, describing its goals, organization, and methods, summarizing its progress, and outlining the work remaining for the future. The first phase of the NPM program (outside the Milky Way) is now nearing completion. A detailed description of the NPM program has been given by Klemola, Jones, and Hanson (1987). Recent results using the NPM data in a study of solar motion and galactic rotation are presented in a separate paper in this Symposium.

A project of a new photographic catalogue of southern stars was proposed in 1977 by Polozhentsev and Potter (1978). The observations for this catalogue were begun in 1982 with an astrograph (field 5°× 5°) placed at the Bolivian-Soviet observatory near Tarija, Bolivia. The astrograph has an aperture and focal length of 23 and 230 cm, respectively. A total of 6420 plates must be photographed to realize the fourfold coverage of the Southern Hemisphere with a 2° overlap in both coordinates and of these 6405 plates have been taken as of January 1, 1987. V.V. Avramchuk, S.P. Pulyaev, Kh.I. Potter (USSR) and R.F. Zalle, V. Yamaguchi, and E. Espinoza took part in the observations.

A high density reference star catalog is being compiled at the U. S. Naval Observatory for the purpose of making new reductions of the Astrographic Catalog. The catalog will be a replacement to the SAO catalog and will be derived from the large photographic catalogs and the modern meridian circle catalogs. It is expected that the final catalog will contain 346, 000 stars, with proper motion mean errors generally or less, on a uniform system, the data having been reduced first to FK4 and then to FK5 using the International Reference Stars (IRS).

A combination of the HIPPARCOS catalogue with fundamental catalogues, such as the basic FK5, shall provide, for the common stars, proper motions (and derived positions) which are significantly more accurate (by a factor of up to 5) than those in the original catalogues. For many other stars, the ground-based observations would also be suited for improving the HIPPARCOS proper motions considerably.

The existing data on proper motions from meridian catalogues and proper motion surveys appear to be reasonably complete for motions larger than 0.24 arc seconds per year and down to the 19th magnitude visual but for motions between 0.24 and 0.18 there exists a lacuna for stars between 8.5 and 11.5 visual which could easily be observed by repeating Carte du Ciel plates.

A review is given of methods that have been proposed for linking the HIPPARCOS Catalogue of star positions to Extragalactic Reference Frames. The methods to be used by the data reduction consortia are outlined briefly.

The mapping discussed in this paper is based on observations obtained from the 21–cm emission line of neutral atomic hydrogen. We will give an overview of the existing large surveys and present a homogeneous datacube that contains the most important surveys. This datacube was created by regridding the original observations, for the surveys included, onto a common denominator grid. Presenting a three dimensional dataset of intensities in one single image is impossible, therefore we made a film that displays in a time sequence a set of cuts (position–velocity maps) through the datacube. The advantage of showing the third coordinate in time is that the eye can now catch continuities in this coordinate that were previously hidden in the data.

Radio continuum surveys give us the fundamental information about the distribution of the radio intensity across the sky. The radio waves originate in three fundamental emitting processes and are measured superposed in the antenna beam. At the lowest radio frequencies (below 10 GHz) the nonthermal emission process (synchrotron radiation) predominates. This radio emission comes from supernova remnants, from the “galactic background” (relativistic electrons diffusing in galactic magnetic fields), but also from extragalactic objects (galaxies, quasars, radio galaxies, etc.). In the frequency range 10 GHz < f < 300 GHz the thermal (free-free) process becomes dominant. In the Galaxy we see the HII regions along the galactic plane. In nearby galaxies we can identify the thermal emission in the disks. Above 300 GHz the dust is seen. This is the boundary region between radio and far-infrared radiation.

The Carte du Ciel was the first photographic survey of the entire sky, extending to 15th magnitude in the blue “photographic” passband. The first Palomar sky survey followed in this tradition, covering the sky north of δ = −30° to a limiting magnitude of ≃ 20 in both blue and visual/red wavelength ranges, while the Whiteoak extension added the fields to declination −42° in the latter color. In the thirty years that have elapsed since the completion of the original survey there have been substantial improvements in emulsions and sesitization techniques, as well as an increase in the wavelength range accessible to photography. These techniques have been ably exploited by the UK Schmidt telescope, and a cursory comparison between any UKST IIIaJ plate and an original POSS 103a-O photograph highlights the considerably improved depth and resolution of the southern survey. We have, therefore, embarked on a second Palomar survey, POSS 2, in an effort to redress the balance. This paper outlines the progress made to date and go on to describe some of the scientific programs that are planned.

The US Naval Observatory has commissioned a short exposure plate for each field in the Palomar Sky Survey II. These plates should provide the necessary intermediate reference frame for the determination of right ascension and declination for faint objects on the “deep” plates using catalog coordinates for bright stars measured on the “short” plate.

The Infrared Astronomical Satellite (IRAS) surveyed 98% of the sky during 1983 at the wavelengths of 12, 25, 60, and 100 μm. The survey was enormously successful, producing catalogs containing more than 300,000 sources as well as digital images of the entire covered sky. The IRAS survey has revolutionized several fields of astronomy and impacted nearly every field. This paper discusses the general characteristics of the IRAS survey and lists the major results obtained so far.

This paper describes the sky surveys carried out over the past 30 years by the three large Schmidt Telescopes; the Palomar 1.2m Schmidt, the ESO 1m Schmidt and the UK 1.2m Schmidt. Developments in photographic technology, the reproduction of the surveys as sky atlases and problems associated with the storage of original plates are discussed. Brief reference is also made to limited purpose surveys which often address one specific research problem and to possible future developments in this branch of astronomy.

An historic review is made of the observation programs with Danjon astrolabes which were carried out or are in progress at the southern hemisphere. The consistency of their results in the research of systematic errors of the FK4 Fundamental System, largely confirmed by other observation techniques, is shown. The Cape and Santiago astrolabe catalogues, the largest ones derived so far for southern stars, are briefly reviewed.

The contribution of the Carlsberg Automatic Meridian Circle to the improvement of the stellar reference frame is reviewed.

The paper tries to provide some background to answer the problem if old astrometric data should be stored. The cases of the AC and the CdC are examined, as well as the storage of some more recent catalogues on optical disc. Finally the necessity of producing general catalogues (of the SAO type) for non-astrometrists is underlined, to satisfy the needs of the astronomical community.

The Astrographic Catalogue has been used to measure the proper motion of the X-ray object 3A2254-033.

The purpose of this study is to compare the quality of three digital image centering algorithms; 1) the fit of marginal distributions by Gaussian, 2) the maximum of the Autocorrelation of a stellar image by its symmetrical, 3) the 2–dimensional fit of stellar images by a mean stellar Profile.

The two main conclusions are: 1) the 3 centering methods give the same accuracy if the star is isolated, bright and unsaturated. But as soon as one of these conditions fails, fast algorithms lack robustness and the only reliable method is the 2-d profile fit, 2) preliminary tests on Schmidt plates digitized with the MAMA (Machine Automatique à Mesurer pour l'Astronomie) show that under the above restrictions, the centering algorithms do not alter the final astrometric accuracy, neither do the digitizing machine.

The prototype of the photoelectric astrolabe, conceived at CERGA with the assistance of the observatories of Paris and Nice, is intended for the improvement of star catalogues. In addition to the technical aspects, we present here some results that indicate the quality of data obtained.

Through multivariate statistical methods, we are trying to detect and separate some “outstanding errors” in visual astnometric data, especially in terms of time, magnitude, colour effects. The methods are illustrated by their application to the Paris Astrolake data.

Because of their early epochs, Carte du Ciel plates are ideal first epoch plates for the study of proper motions. We have tested the astrometric precision of some plates from different epochs using the accurate astrometric star catalogues of Praesepe and Pleiades.