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The Office Administrator, Sandra de Villiers-Soltynski, is thanked for her efficient administrative services to the Council and membership. We wish to thank all the chairpersons and committee members of Branches for voluntarily giving of their skills and time, as well as organisers of lectures, speakers and those who delivered votes of thanks at lectures as well as the South African Astronomical Observatory for lending the boardroom for Council meetings. The Dean and staff in the Science Faculty Office at the University of Cape Town are thanked for kindly accommodating the national office and for sharing faxing and photocopying facilities.

Period-luminosity sequences have been shown to exist among the Semi-Regular Variables (SRVs) in the Magellanic Clouds (Wood et al, 1999), the Bulge of the Milky Way galaxy (Glass & Schultheis, 2003) and elsewhere. Using modern period and revised Hipparcos parallax data, this paper demonstrates that they also appear among the M-giant SRVs of the Solar Neighbourhood. Their distribution in the K, log P diagram resembles that of Bulge stars more closely than those in the Magellanic Clouds. The prevalence of mass-loss among local M-type SRVs and its dependence on period and spectral sub-type are also discussed. K -- [12], a measure of circumstellar dust emission, increases clearly with V amplitude, M giant sub-type and log P., MNRAS (accepted)

Long-term (up to 10000d) monitoring has been undertaken for 41 Seyferts in the near-IR (JHKL). All but 2 showed variability, with K ampl in the range 1.1 mags. The timescale for detectable change is from about one week to a few years. A simple cross-correlation study shows evidence for delays of up to several hundred days between the variations seen at the shortest wavelengths and the longest in many galaxies. In particular, the data for F9 now extend to twice the interval covered earlier and the delay between its UV and IR outputs persists. An analysis of the fluxes shows that, for any given galaxy, the colours of the variable component are usually independent of the level of activity. The state of activity can be parameterized. Taken over the whole sample, the colours of the variable components fall within moderately narrowly defined ranges. In particular, the H-K colour is appropriate to a black body of temperature 1600K. The H-K excess for a heavily reddened nucleus can be determined and used to find E_{B-V}, which can be compared to the values found from the visible region broad line fluxes. Using flux-flux diagrams, the flux within the aperture from the underlying galaxy can often be determined without the need for model surface brightness profiles. In many galaxies it is apparent that here must be an additional constant contribution from warm dust.

In an attempt to discover new southern BL Lac objects, 14 optically featureless objects from the Edinburgh–Cape Survey were selected. Optical polarimetry and spectroscopy, radio and IR observations were carried out in order to improve their classifications. The 14 objects were examined according to special criteria that are described. Their UBV and JHK colour–colour distributions, spectrograms, radio observations and visible-region polarimetry were utilized to conclude that the selected objects are not BL Lacs. Most of them are apparently not extragalactic objects. It is suggested that four of the 14 candidates are DC white dwarfs, one is a QSO, three are DA white dwarfs or sdB subdwarfs, one is a cataclysmic variable, one is a DAO/sdO and another is possibly a DA+dM binary (composite system with a ‘primary’ hot white dwarf and a ‘secondary’ M-type main-sequence dwarf) or a cataclysmic variable. One object is likely to be a subdwarf, while two remain unclassifiable.

A second report on our 4-year survey for long-period variables (LPVs) in the central 24 × 24 arcmin2 of the Galactic Bulge is presented. All four seasons of data have now been reduced and ∼ 350 variables have been found. Preliminary periods have been obtained for most of them. Fifty-five out of 103 known OH/IR stars in the field have been recovered in the K-band.

Two of the five cocoon stars in the “Quintuplet” cluster of young, luminous objects, located about 30 pc in projection from the Galactic Centre, are variables. The nearby “Pistol Star”, also called the “Serendipitous Star”, and a similar object, both suspected on spectroscopic grounds of being Luminous Blue Variables, have indeed been found to vary, confirming their tentative classification. A further variable apparent member of the cluster is probably a Mira in the same line of sight.

A brief description is given of the optical and infrared instruments that are most commonly used on the telscsopes at Sutherland.

A large-format PtSi array (effectively 1k × 0.5k pixels) has been incorporated into an infrared camera intended for survey work using the 0.75-m telescope at Sutherland. The array is very uniform and almost free of cosmetic defects. The camera, its electronics and the operational procedures that we use are described, together with the methods of data reduction. The limiting magnitudes that can be observed in the JHK broad bands are given.

Complete samples of 2MASS stars in 3 fields of differing metallicities (and possibly differing age distributions) have been extracted and cross-correlated with MACHO and ISO data to determine their variability and mass-loss properties. In each M_K histogram a fall-off in numbers is seen above the tip of the RGB. The luminosity of the tip increases with metallicity as does the average J-K at given M_K. The proportion of stars with high H-K increases at lower metallicities. This results from the increasing proportion of C stars. All 3 fields contain similar types of variables, mainly short-period, Mira-like and double-period (having long and short periods). The proportion of variable stars decreases at lower metallicities and the minimum period associated with a given amplitude gets longer. Various trends are seen in the K, log P diagrams of each field. The Magellanic Cloud fields largely resemble each other but the Bulge field is noticeably different. The stars that follow the 'A' K,log P relation in the Bulge hardly extend beyond the M giant tip and the other groups also appear truncated in M_K relative to their Magellanic Cloud counterparts. In the Clouds there are many stars with periods around 200-300d that follow the 'C' or Mira relation but have relatively small amplitudes. The mid-IR sample detected by ISOCAM during the Magellanic Cloud Mini-Survey appears to be reliable and complete for sources with M_K more luminous than -7 mag, i.e., for those close to the top of the AGB. The various colour-colour and colour-magnitude diagrams reflect the increasing dominance of C stars at low metallicity. Mira magnitude vs log P relations exist up to at least 7 microns. Mass-loss from longer-period and double-period SRVs occurs at similar rates in each field, despite differences in metallicity., 14 pages, 16 figures, A&A accepted, better resolution available from ftp://ftp.saao.ac.za/pub/isg

The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on Galactic structure,stellar populations,stellar mass-loss and the recent star formation history of the inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 micron ISOCAM observations - with a resolution of 6'' at worst - with DENIS IJKs data to determine the nature of the sources and theinterstellar extinction. We have observed about 16 square degrees with a sensitivity approaching 10-20mJy, detecting ~10^5 sources,mostly AGB stars,red giants and young stars. The main features of the ISOGAL survey and the observations are summarized in this paper,together with a brief discussion of data processing and quality. The primary ISOGAL products are described briefly (a full description is given in Schuller et al. 2003, astro-ph/0304309): viz. the images and theISOGAL-DENIS five-wavelength point source catalogue. The main scientific results already derived or in progress are summarized. These include astrometrically calibrated 7 and 15um images,determining structures of resolved sources; identification and properties of interstellar dark clouds; quantification of the infrared extinction law and source dereddening; analysis of red giant and (especially) AGB stellar populations in the central Bulge,determining luminosity,presence of circumstellar dust and mass--loss rate,and source classification,supplemented in some cases by ISO/CVF spectroscopy; detection of young stellar objects of diverse types,especially in the inner Bulge with information about the present and recent star formation rate; identification of foreground sources with mid-IR excess. These results are the subject of about 25 refereed papers published or in preparation., Comment: A&A in press. 19 pages,10 Ps figures; problems with figures fixed

A complete sample of 174 M giants classified by Blanco (1986) and later than subtype M0 in the NGC6522 Baade's Window clear field has been investigated to establish some general properties of cool Bulge stars. Photometric information has been obtained from the MACHO database to search for variability and, where possible, to determine periods. Near- and mid-IR magnitudes have been extracted from DENIS and ISOGAL. 46 semi-regular variables and 2 irregulars were found a mongst the 174. Many M5 and all stars M6 or later show variation, whereas earlier subtypes do not. The DENIS I-J and J-K_S colours and the luminosities of the M stars increase with M sub-class. K tends to increase with log P among M-type SR variables. Almost all the variables were detected at 7 microns during the ISOGAL programme. Excess radiation at 15 microns, indicative of heavy mass loss, is associated with very high luminosity and late spectral type. The limit of sensitivity of the ISOGAL survey was such that the non-variables were not detected. Four probable M stars not listed by Blanco (1986), two of which are semi-regular variables, were detected by ISOGAL. In the case of doubly-periodic SR variables, the longer periods have K mags which place them close to the D line of Wood (2000) in a K,log P diagram. The unusual MACHO light curve of one particular star, Blanco 26, shows the commencement of a long-period variation with an anomalously short and sharp event and appears to rule out a pulsational model for this phenomenon., Comment: 10 pages

In external galaxies only the highest-luminosity stellar objects can be studied in individual detail. The Bulge of the Milky Way, however, is sufficiently close that we can observe its constituents down to the Main Sequence. Using information gained from it, we can model the stellar populations of other galactic bulges and early-type galaxies. Early visible-region studies of this kind were conducted by Whitford (1978) and were extended to the near-infrared, where the extinction problems are less severe, by Frogel and Whitford (1987).

Infrared astronomy has been revolutionised in the last few years by the advent of large, sensitive, infrared arrays, and the success of several infrared satellites. This handbook provides a clear, concise and accessible reference on all aspects of infrared astronomy. Throughout, the emphasis is on fundamental concepts, practical considerations and useful data. Starting with a review of the basic infrared emission mechanisms, we are shown how the earth's atmosphere affects and limits observations from ground-based telescopes. The important systematics of photometric accuracy are treated in detail. Spectroscopy - both stellar and otherwise - is explained, and illustrated with useful examples. An important chapter is devoted to dust, which plays such a central role. Finally, the technical background to infrared instrumentation is covered. This volume provides both an essential introduction for graduate students making infrared observations or reducing infrared data for the first time, and a convenient reference for more experienced researchers.

Results from a multiwaveband study of the γ-ray-bright compact radio source 3C 454.3 are presented.

We present the results of an intensive ultraviolet monitoring campaign on the Seyfert 1 galaxy NGC 4151, as part of an effort to study its short time-scale variability over a broad range in wavelength. The nucleus of NGC 4151 was observed continuously with the {\it International Ultraviolet Explorer} (IUE) for 9.3 days, yielding a pair of LWP and SWP spectra every $\sim$70 minutes, and during four-hour periods for 4 days prior to and 5 days after the continuous monitoring period. The sampling frequency of the observations is an order of magnitude higher than that of any previous UV monitoring campaign on a Seyfert galaxy. The continuum fluxes in bands from 1275 \AA\ to 2688 \AA\ went through four significant and well-defined ``events'' of duration 2 -- 3 days during the continuous monitoring period. We find that the amplitudes of the continuum variations decrease with increasing wavelength, which extends a general trend for this and other Seyfert galaxies to smaller time scales (i.e., a few days). The continuum variations in all of the UV bands are {\it simultaneous} to within an accuracy of about 0.15 days, providing a strict constraint on continuum models. The emission-line light curves show only one major event during the continuous monitoring (a slow rise followed by a shallow dip), and do not correlate well with continuum light curves over the (short) duration of the campaign, because the time scale for continuum variations is apparently smaller than the response times of the emission lines., Comment: 39 pages, LaTeX, including 7 PostScript figures; To appear in the ApJ (October 20, 1996) Vol. 470

The near-infrared (JHKL-region) fluxes of about 30 active galaxies, including Seyferts type 1 and 2, have been monitored for periods of up to 20 years at SAAO.

A large-format PtSi array (effectively 1k x 0.5k pixels) has been incorporated into an infrared camera intended for survey work using the 0.75-m telescope at Sutherland. The array is very uniform and almost free of cosmetic defects. The camera, its electronics and the operational procedures that we use are described, together with the methods of data reduction. The limiting magnitudes that can be observed in the JHK broad bands are given.

We describe a versatile array controller developed at RAL and SAAO. The original concept was due to Waltham, van Breda and Newton (1990). A Transputer-based microcomputer forms the heart of the device.

A JHKK’ survey camera based on a 1040 × 1040 PtSi “Charge Sweep Device” has been constructed in a joint programme of the University of Tokyo, the National Astronomical Observatory of Japan and the South African Astronomical Observatory. We describe its design, construction and initial testing.

There is mounting evidence for a high-luminosity population within ~ 0.5° of the Galactic Centre. The luminosity function of the Sgr I field, the high end of which is dominated by AGB stars, is discussed and taken as typical of the background population to be expected in the Bulge. It is shown that the high-luminosity objects near the Centre cannot be AGB stars. From studies of the counterparts of IRAS sources it appears that some of them may be coccoon stars and other young objects associated with compact HII regions. The cluster near G0.15-0.05 contains an M supergiant, several luminous blue objects (including at least one HeI emission-line star) and some spectroscopically featureless infrared objects.

We describe a versatile array controller developed at RAL and SAAO. The original concept was due to Waltham, van Breda and Newton (1990). A Transputer-based microcomputer forms the heart of the device.

Simultaneous observations of 3C 279 at radio, millimeter, near-infrared, optical, ultraviolet (with IUE) and X-ray (with ROSAT) wavelengths were obtained in 1992 December-1993 January, during a three week pointing at the source by the Compton Gamma Ray Observatory. The blazar was in a quiescent or 'low' state during this period. Comparing the multiwavelength energy distribution to that from 1991 June, when 3C 279 was in its brightest recorded gamma-ray state, we find the following: (1) 3C 279 faded dramatically at all frequencies above 10(exp 14) Hz, while the flux variations at low frequencies (radio to millimeter wavelengths) were minor. (2) The near-infrared-optical-ultraviolet spectral shape was softer (steeper) in the quiescent state, and the X-ray spectra also appear softer, although the spectral indix measured by ROSAT refer to a lower energy band than that measured earlier with Ginga. (3) The ratio of the gamma-ray luminosity to that across all other frequencies decreased from a value of approximately equal to 10 in the flaring state to a value approximately equal to 1 in the quiescent state. These findings imply that the production of gamma-rays is closely related to the optical-ultraviolet continuum, in agreement with models where gamma-rays are produced through inverse Compton (IC) scattering by relativistic electrons emitting the synchrotron continuum. The observed nonlinear relation between the synchrotron and IC requires both a change in the electron spectrum and an associated change in the seed photons.

The Seyfert 1 galaxy NGC 3783 was intensely monitored between 1991 December and 1992 August. We present the results from the ground-based observations in the optical and near-IR, which complement the data-set from the IUE, discussed elsewhere. Spectroscopic and photometric data from many observatories were combined in order to obtain well sampled light curves of the continuum and of H-Beta. During the campaign the source varied significantly. The light curves of the optical continuum and of H-Beta are similar to those obtained with the IUE. The near-IR flux did not vary significantly except for an increase at the end of the campaign. The optical continuum and the flux of H-Beta lag the UV continuum by 1 day or less and by 8 days respectively. These results confirm that the continuum variations are simultaneous or have a very small lag across the entire UV-optical range, and that the lines of NGC 3783 respond to ionizing continuum variations with less delay than those of NGC 5548. As in NGC 5548, the lag of H-Beta is greater than those of the high ionization lines.

Les observations IR des supergeantes des Nuages de Magellan ont permis d'identifier un grand nombre de types differents identifies

The outstanding feature of the last triennium was most certainly the abrupt generalisation of the use of array detectors, particularly CCDs (charge coupled devices). The latter pervade all subdivisions of instrumental astronomy. The gains achieved by their high quantum efficiency, their stability, their capability of delivering immediately recordable signals which can be processed by appropriate computational means, have been the cause of spectacular progress regarding the photometric precision of weak signal measurements.