The use of small telescopes for the production of significant research is examined from the points of view of cost-effectiveness, notable successes already achieved, the advantages over large telescopes in the areas of efficiency, availability, flexibility and serendipitous and speculative observation. It is concluded that small telescopes have an increasingly important role to play in modern astronomy.

We describe the performance expected from a new generation of CCD imagers being developed by Tektronix, and we indicate the types of applications, instruments, and computer systems that can best take advantage of these devices on telescopes both large and small. Since these new detectors will be able to reach very faint limits even on small telescopes, we also describe cost-effective television viewing systems suitable for object acquisition and guiding.

CCD photometry with small telescopes often complements the use of such detectors on larger telescopes and in addition it is ideally suited to projects, such as determining variable star light curves, that require considerable amounts of observing time. Following a discussion of some of the techniques found useful for producing accurate CCD photometry, the results of several projects carried out with the SAAO 1m CCD camera are presented.

Small automatic telescopes have been used for several years to make wide band, differential photometric observations of brighter variable stars. For example, a single automatic telescope located in Arizona has been used to study essentially the entire class of RS Canum Venaticorum binaries. These stars have changing spot structures that require once-a-night photometric observations - an ideal job for an automatic telescope located in the clear skies of Arizona. The operation of such automatic systems has become so routine that an “Automatic Photoelectric Telescope Service” now makes photometric observations for any institution so requesting. A list of stars is sent to the Arizona site of this service, and every three months the observational results are returned, with the cost typically being similar to the publication page charges. Currently the use of automatic telescopes is being extended to fainter stars and narrower bandwidths. For instance, a highly specialized one-meter telescope has been designed for automatic observations of Ca II K-line emissions from brighter active chromosphere stars. Further extensions of such automation seem likely.

The Hamamatsu R943-02 photomultiplier appears to be suitable for UBV(RI)c photometry. This paper discusses the tube's characteristics on the basis of one year's experience in the use of such a device on the 0.5m telescope at Sutherland.

A modern photometer designed for variable star observation should meet the following specifications: 1. Simultaneous measurements of object, comparison star and sky in order to allow compensation of changing atmospheric transparency and background radiation. 2. Simultaneous multicolor measurements of each channel yielding high efficiency and accurate colors. 3. Coverage of a large wavelength region (U-I) with high time resolution. A photometer, fitting these requirements has been designed at the Universitäts-Sternwarte München. In principle light from three sources in the focal plane of a telescope is guided through optical fibers to three spectrographs, each splitting the incoming signal into five wavelength regions. The resulting 15 output channels are linked to photon counting detectors. Their signals finally are processed in a microcomputer.

The classical method of discovering objects that vary in position and/or time is to examine well-matched pairs of plates using a blink comparator. This method, being manual, is slow, subjective and, unless several matched plate pairs are used, suffers from incompleteness. The combination of wide angle Schmidt cameras, high speed measuring machines and sophisticated computer software has enabled objective methods for searching for variable objects to be devised. Using such methods it is possible to intercompare stacks of plates digitally. The deepest plate may be used as a master in position and magnitude, eliminating the need for the rest to be well matched. Following measurement and analysis it is a relatively simple matter to prepare lists of variable objects such as RR Lyrae stars, Mira long period variables, cataclysmic variables, active galaxies, comets and asteroids which may then be used as a basis for more intensive study by smaller dedicated instruments.

This, however, is only one aspect of the cooperation possible between Schmidt telescopes, measuring machines and small telescopes. In projects involving the study of large numbers of mainly non-variable objects (stars or galaxies) the small telescope has a most important role to play in providing photoelectric magnitude calibrations to convert machine measured magnitudes to a standard system. To date this has been the principal use to which the small telescope has been put, even in the study of the distribution of faint galaxies from Schmidt plates it was a small telescope which provided the necessary measurement of the background sky brightness.

A further dimension is provided by the addition of an objective prism to the Schmidt camera. In this case objects readily detected include emission line stars and galaxies. The calibrating power of the smaller instrument is now of value in providing standard galaxy radial velocities to calibrate red shifts measured from the very low dispersion prism.

With a 60-cm telescope at an outstanding site, it is possible to coordinate observations with larger telescopes and with satellites to provide monitoring of interesting objects. The University of Toronto Southern Observatory at Las Campanas, Chile, has been involved in several such programmes, in support of large telescopes at Tololo, La Silla, and Mauna Kea, in addition to the I.U.E., EXOSAT, and other satellites.

A system with an electronomulitplier of two-stage microchannel plate and a vidicon TV camera is developed for two dimensional photon-counting imaging and is applied for astronomical observations at the Nasmyth focus of the 75cm alt-az telescope of the Sundai Observatory at Kita-Karuizawa (SOK). Some test results are shown here.

Three low-dispersion (15–50A/mm)−1 spectrum scanners have been developed at Fick Observatory as instrumentation for small telescope research and teaching activity. They have been applied in solar eclipse, zodiacal light, stellar, and comet research programs. The two plane grating spectrometers and one holographic grating instrument have been employed on telescopes ranging from 7.6 to 61 cm aperture, generally with f/5 to f/8 configurations. Recently, one of the plane grating instruments has been modified to perform as a four-channel spectrometer for quantitative spectral classification and composite spectra studies. This instrument is also being used to make spatial-spectral studies of the coma of Comet Halley, and other recent comets.

Many small observatories are associated with undergraduate colleges at which research programs must be integrated with a broad spectrum of educational programs. The instrumentation and observing programs of Grinnell College's Grant O. Gale Observatory have been designed with this constraint in mind. Although modest by large observatory standards, the instrumentation incorporates contemporary technology such as solid state detectors and microcomputer control. Because a variety of student projects as well as a multi-faceted research program must share the telescope, often during a single night, the auxiliary instrumentation has been designed to eliminate almost all hardware changes associated with changes in observing technique (spectroscopy vs. photometry, for example). The auxiliary instruments are all interfaced to the data acquisition computer, which can also communicate with the telescope control system. Research programs have been selected both on the basis of scientific merit and compatability with our capabilities and constraints. We therefore concentrate on long-term observing programs which cannot be carried out at most large observatories and attempt to take advantage of our flexible instrumentation and computer-processing capability.

An automated photoelectric four-star photometer has been designed for use on the 46-cm reflector at Appalachian State University's Dark Sky Observatory. The system will be composed of integrated detector-amplifiers, stepper-motor controlled x-y stages, and automatic counters.

An 8-cm optical telescope is constructed for use at the south pole. It is designed to make photoelectric observations of selected stars continuously through an austral winter. The automated operation is controlled by a computer. The aim is to study the variability of the star γ2 Velorum as well as the condition of the polar sky and the performance of the instrument.

A new astronomical system is nearing completion at U.N.S.W. in which a charge coupled device (CCD) array detector is matched to a Schmidt telescope, with the observations completely analyzed on-line. We have modified a Baker-Nunn satellite tracking camera, with its excellent 0.5m, f/1 super-Schmidt optics, converting it into a computer-controlled equatorially-mounted astronomical telescope. The telescope is expected to be located at Siding Spring Observatory in north-western New South Wales.

Automatic photoelectric telescopes now exist. They are currently doing precision photometry of variable stars, fully automatically. More such telescopes will exist in the near future, and they will be doing automatic photometry of all sorts.

Why are Canadian astronomers so keen on going to Chile to study the stars with a small telescope? First and foremost, the southern half of the celestial sphere contains scientifically exciting and unique objects which have long been neglected. Secondly the rapid growth of Canadian cities and the cloudy Canadian climate renders nearby telescopes less effective than they used to be for some (though not all) types of research.