P. R. Jorden

Multiwavelength isophotal data for southern elliptical galaxies

Isophotal profiles are presented for 40 southern elliptical galaxies derived from CCD imaging with B, V, R, I, and Gunn z filters. The data show excellent agreement with other CCD observations. The principal use of these data will be to search for wavelength dependences of isophotal parameters

A CCD image of the galactic centre

Because the galactic centre lies behind approximately 27 magnitudes of visual extinction, observations at visible wavelengths are impossible. The recent introduction of charge-coupled devices (CCDs) to astronomy represents the first opportunity to use sensitive area detectors in the near IR. Using a cooled CCD, we have obtained an image of the galactic centre at an effective wavelength of 0.9 µm. Two unresolved sources were found, separated by 3 arc s along the galactic plane. The detection of the two sources was confirmed by a further observation the following night. The possibility that the new sources are foreground objects cannot be completely ruled out; however, their positions are remarkably close to those of the non-thermal radio source and the 2.2 µm source IRS-16. While it is possible that the new sources could be a pair of highly reddened individual stars or compact clusters, it seems more likely that they are two compact H II regions seen in line emission.

The Royal Greenwich Observatory (RGO) Charge Injection Device Camera System

A camera system has been constructed using the 188 x 244 element Charge Injection Device (CID) and a micro-programmable controller. The CID is used in a cooled direct imaging mode and controlled by a bit-slice sequencer. An LSI-ll computer with FORTH language is used. Results obtained with direct imaging, polarimetry and spectrograph work are presented.

Laboratory And Astronomical Comparisons Of RCA, GEC And Thomson CCDs

Although current interest is focussed on the emergence of large CCDs from Tektronix, for many applications smaller devices based on the TV imaging format are still relevant. Several manufacturers produce CCDs of this size, and deciding which to use for a particular application is of some importance. Over the past three years, the general purpose CCD camera system developed at the Royal Greenwich Observatory (RGO) has been used to test, optimise and compare various types of CCD with further work being carried out on a variety of telescopes. The results of this work are described, dealing not only with the obvious features such as noise and quantum efficiency, but the more subtle aspects such as low light level performance and temperature dependence. The astronomical relevance of the various factors is considered and suggestions made as to the suitability of each type of chip for various types of observation. Finally, the future of these TV format CCDs is considered in the light of the likely availability of much larger alternatives.

Royal Greenwich Observatory (RGO) Charge-Coupled Device (CCD) Camera

A liquid nitrogen cooled CCD camera utilising the RCA 53612 thinned CCD is described. It was constructed primarily for direct imaging at the prime focus of the Anglo Australian Telescope and is now installed as a common user instrument. The camera head, drive electr-onics and microprogrammable controller are briefly described. The camera has been designed to accommodate other CCD chips with minimum modification: many operating modes are available under software control. Operating characteristics and some astronomical results are presented.