This paper describes the building of a 32cm telescope which had been designed from the beginning to undertake high precision photoelectric photometry.

The Sundai senior high school built a telescope with an alt-az mounting and an aperture of 75cm. A photographic camera at the prime focus, and an SIT camera, a photomultiplier, and a spectrograph at the Nasmyth focus are prepared. Time needed for the exchange between instruments is in less than a minute. Therefore, effective observations are performed by changing the instruments which are proper for the sky condition at the observed night.

We have developed a single-channel photopolarimeter to measure polarization ∼1%, with an accuracy of 0.1% or so. Laboratory tests show that the performance of the instrument is as per the requirements.

The astronomers at the University of New Mexico are applying the finishing touches to their CCD project. We addressed many issues during the course of this project, such as whether to build or buy the CCD camera system, what upgrades our telescope and observatory were in need of, and what kind of image processing capability the instrument demanded. Our decisions and solutions are presented as a guide to other institutions which may be considering CCD instrumentation for their small telescopes, especially since most face the same constraints that we do: limited money and manpower.

The telescope will be used at the Cassegrain focal plane only. Two interchangeable systems of secondary optics are required to give relative apertures of:

1. (a) f/13.5 for spectroscopy and photometry over a small field.

2. (b) f/8 for photography over as wide a field as practicable.

The seven inch transit circle near Blenheim, New Zealand is intended in conjunction with the six inch circle at Washington, to produce a fundamental catalogue and to re-observe the Southern Reference Stars.

A polarimeter for the measurement of Stokes' parameters for stellar and quasi stellar objects in specific wavelength regions has been reported. The variable retardation and dispersive property of a small angle Babinet Compensator has been exploited for such measurement. The theoretical basis of the method is given in detail.

A photometric system capable of simultaneous dual channel operation has been developed for use in NZ. The photometer head unit, developed and constructed by the University of Texas at Austin, permits simultaneous observation of two stars using suitable optics and mechanically coupled photomultiplier systems. The instrumentation and control system is centred around a DEC micro/PDP-11 computer and incorporates general purpose hardware and software developed specifically for the system.

A CCD detector has been developed for photometry and image detection with the 60cm reflector at Kagoshima Space Center. The structure and the manipulation of the instrument were simpified by the use of Peltier devices for cooling the CCD in order to eliminate thermal noise. A micro-computer system is used to control the instrument and process the data. A test observing run has demonstrated that a photometric sensitivity of 20th magnitude in the W band(3800-7000 Å) can be achieved in a 3600sec exposure.

A newly developed catadioptric optical system and a modified york-type equatorial mounting were designed and constructed. This telescope will be installed at Saipan Island for observing Comet Halley in Feb.-Apr. 1986.

We have constructed an optical fiber link between the CTIO 1.5 meter telescope and the instrument development laboratory located in the 4 meter telescope building. We have successfully observed a variety of objects using the 4 meter échelle spectrograph fed with light from the 1.5 meter telescope. These first observations indicate that the system is extremely stable, both in its spectral response and in wavelength calibration. The principal aim of the project was to provide the capability of recording high resolution spectra at the 1.5 meter, using linear detectors. Even with the loss of light associated with the use of the fiber, a conservative estimate of the speed of the system indicates a factor of 20 increase in speed over the existing coudé spectrograph.

The effectiveness of existing telescopes can often be greatly enhanced through upgrading. Two important questions which should be answered in the planning stage are discussed, based on recent experience in upgrading two Lowell Observatory telescopes.

A new photometer is described which has some unique optical features. Emphasis is given to those features that improve the measurement precision and efficiency of use.

This telescope was designed for determining the trigonometric parallaxes of faint stars. The otpical configuration is a Ritchey-Chrétien system and has only a f/10 Cassegrain focus for photographic work.

The mounting is a combination of fork and yoke frame which can reduce the flexure due to gravity. A high speed digital servo-system was adopted for controlling and driving the telescope. At present some photographs of Comet Halley have been obtained.

The dominant trend within stellar photometry in recent years has been an increase in the number of intermediate and narrow-band photometric observations, particularly with small telescopes. Recent examples illustrating the scope and emphasis of such programs are reviewed. It is concluded that with continuing improvement in detector technology and telescope automation, small telescope photometry will grow in importance.

A number of promising observational programs involving linear polarization measurements are discussed after consideration of the observational limits based on telescope size and instrumental accuracy. These projects include studies of interstellar extinction, circumstellar shells and extended envelopes, inhomogeneities on stellar surfaces such as nonradial pulsation, magnetic stars, and interactive binary systems.

The most promising mechanism for the formation of contact binaries involves the orbital angular momentum loss (AML) and the resulting orbital decay of detached but close synchronized binaries. The efficiency of magnetic wind braking should abruptly decrease upon formation of a contact binary because of the transformation into a system of earlier spectral type and (possibly) of longer orbital period. The new primary of the contact system should have convective zone thinner than indicated by the surface temperature of the common envelope. The decrease in the coronal (X-rays and radio) activity of contact binaries, which is indeed observed, is used as an agrument that the AML efficiency in contact is relatively low and that the contact stage is considerably prolonged relative to adjacent stages. This small modification to the AML models is capable of explaining why many different contact binaries are observed in old systems like NGC188. The AML evolution is not the only mechanism leading to formation of contact binaries; some of them may have originated via Algol-like evolution. Thus, the observed contact binaries are probably a mixture of systems formed in different ways.

Discussed are meritorious projects for small and moderate telescopes in the field of interacting binaries with non-degenerate component stars. These interacting binaries are undergoing a mass transfer process, as a consequence of which the mass-accreting star may be partly or completely hidden in an accretion disk, and the system may be shrouded in dense clouds of circumstellar matter. This makes the observation, interpretation and modeling difficult; but it is important to study these “bizarre” binaries since they tell us a lot about stellar evolution in binary systems. Needed are various observations: Timing of eclipses; observation and re-observation of light curves in several colors (in uvby rather than in UBV; and in the red and infrared); radial velocity studies; spectrophotometry of crucial regions of the spectrum. As examples for these needs, the following systems are discussed in some detail, and their problems revealed: RX Cassiopeiae, W Serpentis, and W Crucis as examples of the strongly interacting systems (W Serpentids); U Sagittarii as a helium-rich binary in a rare evolutionary stage, which will be better understood if we decide whether the star eclipses or not; and KX Andromedae as a representative of non-eclipsing interacting binaries and of Be and shell stars, which may or may not be binaries.

The techniques, advantages and limitations of photoelectric observations of occultations of stars by the Moon are reviewed. The results for timings, lunar limb slopes, double and multiple stars, and the determination of angular diameters of stars are considered. Possible effects of lunar limb irregularities are discussed. Observers are strongly recommended to pursue the upcoming series of occultations of Antares and other important stars.