NEWSLETTER news. G'day from Coona from G'day Site special ó AAT and UKST UKST and AAT ó special Site news Local Starformation al.) in et spiralProust (Dominique supercluster Shapley the galaxies of structure The (Sonia Cianci) Star formationHunstead) Dick in& Baker distant(Jo quasars radio-loud in absorption Associated cluster galaxiesParker) (Quentin known? (Warricknebula planetary largest The Couch et al.) and future plans. See pages 10 to 21. to 10 pages See plans. future and In In in this issue we focus on the staff and facilities changes at the telescopes. We bring you up to date on on site and AAT; the for program seeing the site, the greening protection, site as such issues instrumentation current on updates programs, completed and instruments retired ó instrumentation 10 22 3 4 6 7 9

contents

NUMBER 9 4 A U G U S T 2 0 0 0 0 0 2 T S U G U A 4 9 NUMBER ANGLO-AUSTRALIAN OBSERVATORY DIRECTOR'S MESSAGE DIRECTOR'S DIRECTOR'S MESSAGE

This issue of the AAO Newsletter highlights the work of staff at Siding Spring. This has been the busiest year ever for commissioning of new instruments and facilities at Siding Spring. Already this year, the AAO has successfully commissioned the new prime focus unit, the SPIRAL integral field spectrograph, the oil cooling facility, the Apogee camera replacement for the Quantex TV in the Cassegrain A&G Unit, imaging polarimetry with Taurus and the wide field imager (WFI). Still to come this year are IRIS2, 6dF and the Tokyo/Peterson CCD camera and the new telescope control system for the UK Schmidt.

As can be seen from the above list, significant focus is being placed on infrastructure (e.g. oil cooling, A&G unit, telescope control). Improving infrastructure, either through the replacement of legacy systems, or the enhancement of existing systems, forms a key part of the AAOís strategy for the future as outlined in the document ìPartnership in Innovation: The AAO of the Futureî (available from http://www.aao.gov.au/about/future-aao.pdf). The future success of new instruments such as WFI and AAW (see below) are underpinned by infrastructure. Over the next 2-3 years the AAO has plans to extend its campaign on infrastructure. These plans include replacing the existing optical CCD controllers with the new generation AAO-2 controllers, removal of the VAX and Interdata Telescope Control Systems and further investment in the 1- arcsec seeing campaign.

In the broader context, the ìAAO of the Futureî has provided a direction for the Observatory which has met with approval from the user communities. At their recent meeting in Oxford, the Board endorsed the strategy outlined in the document and welcomed the intention of the UK and Australian nominated persons on the Board to use it as a basis to work towards an agreement between the respective agencies regarding the future of the AAO.

The Board also endorsed the strategy behind the instrumentation plan outlined in "The AAO of the Futureî. In particular, they encouraged the AAO to fast-track the design study for AAW. David Lee provides a full description of the AAW project in this newsletter. AAW represents an exciting new program for the AAO, capable of extending the existing spectroscopic limit of 2dF by over a magnitude. This opens up a new area of astronomical parameter space for the AAO, allowing the AAO to play a major role in the spectroscopic follow-up of the digital sky surveys of the next decade (VISTA, SDSS). It may be hoped that AAW will provide the same level of scientific impact in 2005 and beyond as 2dF does at present.

Brian Boyle

Next Issue: If you have some recent results based on AAT or UKST data, or other items of interest, please send articles to [email protected] by October 23, 2000. Article length can vary from 2 paragraphs to 2 pages, with preference for plain or latex text and gif or postscript images. The editor would like to thank the staff at site for their help in compiling this special issue, in particular Jonathan Pogson for the photographs used throughout, and Helen Woods for her editorial assistance.

ANGLO-AUSTRALIAN OBSERVATORY page 2 NEWSLETTER AUGUST 2000 STAR FORMATION IN SPIRAL appears in one of the spiral arms of M83, but is not present in the Ha image (see Figure 1). This suggests GALAXIES HIGHLIGHTS SCIENCE a superñassociation of more evolved stars, such as Sonia Cianci (U. Sydney) A stars, within the spiral arm. Such an association would raise the question of how these stars have overcome Universal star formation laws, which linearly relate the rotational shear to remain together as a group, within bolometric Ha or UV flux of a source to its current star the arm. Galactic rotation in M83 of ~200 km/s (de formation rate, are based on the simple assumption that Vaucouleurs et al. 1983) would result in shearing that UV radiation is either observed directly (Madau et al. would be apparent over a region of evolved stars. We 1996) or re-processed into Ha (Kennicutt 1983). These need to investigate this region in M83 further ó models, however, do not allow for environmental factors: observations of Ha absorption would confirm it to be a tides or bars; flocculent or dominant spiral arms; bulges region of more evolved stars. or disks. If this region in M83 is a superñassociation of more In order to test the validity of these relationships, we evolved stars, it is possible that the region is large obtained Ha and Hb images of a selection of nearby enough to overcome rotational shear with its own gravity. spiral and dwarf irregular galaxies over a range of Hubble Also, theories suggest that the shear within the spiral type and luminosity, using the TTF in February 2000. arms is much lower than between the arms, possibly We also have UV images of these galaxies, taken from decreasing to zero, due to differential streaming of the the Ultraviolet Imaging Telescope (UIT) database. compressed gas as it arrives at the spiral arms (Elmegreen 1994). This would allow for a large Differential comparison between the Ha (corrected for association of stars to remain together longer within a extinction by comparison with Hb) and UV will allow us spiral arm than at other locations where the shear is to understand in detail whether universal star formation much greater. laws have any foundation. Any correlation between the Ha and the UV would indicate that some fraction of the An accurate correction for local dust extinction is UV escapes and is not contributing to the Ha images. important for all our comparisons between the UV and This would mean that star formation laws could not be Ha. The development of a doubleñband thin film based exclusively on Ha measurements. interference filter, transmitting at Ha and Hb, will enable more accurate corrections to be obtained (see Cianci Initial visual comparisons between the Ha and the UV et al. 2000 on multiñband filters). Used with the TTF in images seem to show some correlation between Ha charge shuffling mode, the doubleñband filter will provide and the UV emission regions, as can be seen in the quasi-simultaneous observations at Ha and Hb by spiral arms of M83 (NGC 5236) (Figure 1). These regions alternately tuning the TTF between the two widely delineate where the most recently formed stars are to separated hydrogen emission lines. This allows for be found. Further quantitative comparisons are required, easier averaging of atmospheric variations over the two however, to test current star formation laws. wavelengths. Thus, the local dust extinction correction Other interesting features shown by the comparison of for nearby galaxies, measured with the Ha/Hb ratio, will the UV and Ha can be used to investigate aspects of be more accurate than with separate single line galactic evolution. For example, a bright UV region measurements from conventional imaging.

References

Cianci, S. et al. 2000. ASP Conf. Series, 195, 601 Elmegreen, B. G. 1994. ASP Conf. Series, 66, 61 Kennicutt, R. C. 1983. ApJ, 272, 54 Madau, P. et al. 1996. MNRAS, 283, 1388 de Vaucouleurs, G. et al. 1983. ApJS, 53, 17

Figure 1. The nearby spiral galaxy M83 (NGC 5236) in Ha (656.3nm) + continuum, obtained with the TTF (left), and in UV (152.1nm), from the UIT database (right). The circles highlight a region of stars that is bright in the UV, but not present in Ha ó possibly a superñassociation of more evolved stars.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 3 AUGUST 2000 We selected targets from red ESO/SRC sky survey THE STRUCTURE OF THE plates scanned by the MAMA machine at Paris

CEC HIGHLIGHTS SCIENCE SHAPLEY SUPERCLUSTER Observatory. The fields observed were the standard Dominique Proust (Meudon), Quentin survey fields nearest to the centre of the cluster (13:25:00 Parker (ROE) & Michael Drinkwater ñ31:00:00 B1950). These covered an area of 77 deg2 (U. Melbourne) allowing us to probe the limits of the SSC out to radii as large as 8 degrees. The Shapley supercluster (SSC) has been investigated by numerous authors since its discovery in 1930 We defined a sample of galaxies to a limit of R < 16, (Quintana et al. 1995). It lies in the general direction of corresponding (assuming a mean B ñ R=1.5) to B < 17.5, the dipole anisotropy of the Cosmic Microwave the nominal galaxy limiting magnitude of the FLAIR-II Background (CMB), and is located at 130 hñ 1 M p c b e y o n d system. This corresponds to an absolute magnitude of 75 M = ñ19 at the Shapley distance of 200 h ñ 1 M p c . T h i s the HydrañCentaurus supercluster (~50 Mpc away from B 75 us). It consists of many clusters and groups of galaxies gave samples of 600 ñ 1000 galaxies per field. in the redshift range 0.04 < z < 0.055. The central cluster We observed a total of only 3 fields with the FLAIR-II A3558 has also been measured with a ROSAT PSPC spectrograph in 1997 May and 2 fields in 1998 April due observation by Bardelli et al. (1996) who derive a total to poor weather, each time with an allocation of 8 halfñ mass of M = 3.1 x 1014 M within an Abell radius of tot sol nights. The 1999 run was much more successful with 7 2 Mpc. Several other x-ray clusters form part of the fields observed. The data were reduced as in Drinkwater Shapley supercluster. It is recognised as one of the most et al. (1996) using the Dofibers package in IRAF. massive concentrations of galaxies in the local universe, Redshifts were measured for absorptionñfeatured so it is of particular interest to consider its effect on the spectra using the cross-correlation task XCSAO in dynamics of the Local Group. In Quintana et al. (1995), RVSAO (Kurtz & Mink 1998). Spectra showing both it was estimated that for Wo = 0.3 and Ho = 75 km/s/ absorption and emission features were generally Mpc the gravitational pull of the supercluster may account measured with the two tasks XCSAO and EMSAO and for up to 25% of the peculiar velocity of the Local Group the result with the lower error used. required to explain the dipole anisotropy of the CMB radiation, in which case the mass of the supercluster Results would be dominated by interñcluster dark matter. We obtained a total of 645 velocities from the 3 observing Previous studies of the Shapley supercluster have runs, which represents a substantial improvement of concentrated on the various rich Abell galaxy clusters the complete velocity catalogue, especially in the in the region, but this might give a very biased view of regions between the known Abell clusters. Parts of the the supercluster. We are continuing this project, using results have been published (see Drinkwater et al. 1998, data from wideñfield multiñfibre spectrographs to 1999; Parker et al. 2000). measure many more galaxy redshifts and get a more Figure 1 shows the resulting distribution of galaxies complete picture of the composition of the SSC. Our towards the Shapley supercluster as cone diagrams in main aims are firstly to define the real topology of the Right Ascension and Declination. The importance of SSC, and secondly to analyse the individual X-ray the SSC in this region of the sky is demonstrated by clusters that are true members of the Shapley the fact that fully three quarters of the galaxies we Supercluster in order to estimate the cluster masses, measured belong to the SSC with velocities in the range and investigate suspected sub-structure. Additional 7500 ñ 18500 km/s. In both plots the new 1999 data observations are planned before we present a full are indicated by open circles (339 velocities) to analysis of the dynamics. emphasise their impact. It can be seen that by probing Observations large regions of the SSC away from the rich Abell clusters, we have revealed additional structures. In 1997 we started a campaign to obtain complete samples down to the same magnitude below L for each In agreement with previous work we note the presence * cluster. Each selected cluster has a projected diameter of the foreground wall of galaxies (HydrañCentaurus of 2.5 to 3.0 degrees, so the FLAIR-II system on the region) at V ~ 4300 km/s. This distribution can be related UKST with a 5.5 x 5.5 deg2 field is an ideal facility for to the nearby cluster A3627 associated with the ìGreat this project. The very wide field also permits us to probe Attractorî (KraanñKorteweg et al. 1996). Concerning the the regions between the dominant clusters neglected in main SSC, our new data revise our knowledge of its previous observations. largeñscale structure by measuring a large number of galaxies away from the rich Abell clusters previously

ANGLO-AUSTRALIAN OBSERVATORY page 4 NEWSLETTER AUGUST 2000 CEC HIGHLIGHTS SCIENCE

Figure 1: Cone velocity diagram in Right Ascension (left) and in Declination (right) for galaxies in the Shapley Supercluster region. The diagrams cover R. A. from 12h15 (bottom) to 14h30 (top) and Declinations from ñ26o (top) to ñ38o (bottom). Filled circles: data from the literature and previous FLAIR observations. Open circles: our new 1999 observations. studied. The majority of the galaxies we observed were over the whole region we surveyed to the South of the part of the SSC, so our principal result is to show that core of the SSC. We detected an additional 426 the SSC is bigger than previously thought. Looking at members of the SSC in our whole survey area, increasing the cone diagram in R. A. we can see that the SSC is very significantly the number of SSC galaxies. Our new separated into two components in velocity space as data suggest that the SSC is at least 50% more massive previously thought; the nearer one at V =10740 km/s, with a significant part of the extra mass in the closer to the East of the main concentration at V =14850 km/s. sub-region. The SSC therefore has a more important However clumps of objects seem to link these two main effect on the Local Group than previously thought, structures which were not observed before. Moreover a although we defer a detailed calculation until we have large concentration of objects close to R.A. = 13 h and additional data. V =16000 km/s is connected to the main structure. We now plan to measure a larger region further from the It can be see from the Declination cone diagram that centre of the SSC in the range 12h30 < R.A. < 14h30 the Southern part of the SSC consists of two large and ñ23o < Dec.< ñ42o in order to (i) define the complete sheets of galaxies, of which the previously measured topology of the SSC, (ii) analyze the individual Abell Abell Clusters represent the peaks of maximum density. clusters contained in the SSC and (iii) determine more The Declination plot also reveals a long structure at precisely its gravitational effect on the Local Group. An V =15000 km/s present over the whole range observed extended catalogue of galaxies has been obtained from (ñ25o < Dec. < ñ38o). Moreover, new measured galaxies red ESO/SRC SSC neighbouring plates scanned by the tend to establish a connection between the Hydrañ MAMA machine at Paris Observatory. However our Centaurus region and the SSC. These new observations recently allocated 7 nights in May/June 2000 did not mean that we must modify the conclusions of previous provide significant new results because of an papers about the overall shape of the SSC. It was exceptionally bad weather period at Siding Spring (only concluded from the velocity distribution of the clusters 2 clear nights). The new UKST spectrograph, 6dF, with that the SSC was very elongated and either inclined its 150 fibres in a 6o field will be the ideal facility to towards us or rotating. The SSC extends as far as our complete our study of the Shapley supercluster. measurements to the South, so we find it is not We wish to thank the UKST and AAT staff, especially Paul elongated or flattened. We now suggest that it is more Cass, Malcolm Hartley and Ken Russell, for their excellent complex still, being composed of the known Abell support of our observations. DP and MJD acknowledge support from an Australian Research Council IREX grant. clusters embedded in at least two sheets of galaxies of much larger extent. References Bardelli S. et al. 1996. A&A, 305, 435 Conclusion and prospects Drinkwater M.J. et al. 1996. MNRAS, 279, 595 Drinkwater M.J. et al. 1998. XIVe IAP conference "Wide Our new observations of galaxies towards the Shapley Field Surveys in Cosmology", Paris, ed. S. Colombi supercluster have, by surveying a large area away from et al., p392 known clusters, revealed substantial new large Drinkwater M.J. et al. 1999. PASA, 16, 113 structures in the region. The cluster is part of a much KraanñKorteweg R.C. et al. 1996. Nature, 379, 519 Kurtz M.J. & Mink D.J. 1998. PASP, 110, 934 larger structure than was apparent from the previous Parker Q.A. et al. 2000. to be published in A&AS observations, extending uniformly in at least two sheets Quintana H. et al. 1995. AJ, 110, 463

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 5 AUGUST 2000 STAR FORMATION IN DISTANT directly. A major restriction in this context has been CEC HIGHLIGHTS SCIENCE CLUSTER GALAXIES that distant cluster studies have been confined to the central core regions, where the galaxy population is Warrick Couch (UNSW), Richard Bower, dynamically well mixed and any stratification associated M. L. Balogh, Ian Smail (Durham) & Karl with the infall process has been erased. Glazebrook (JHU) In an attempt to overcome this problem, the recently Compared to their presentñday counterparts, the cores upgraded Low Dispersion Survey Spectrograph of distant rich galaxy clusters are conspicuous for their (LDSS++) was used to conduct a survey of Hañemitting much larger populations of galaxies which have been galaxies in distant clusters over a very large field. By hosts to significant star formation activity. This is now using Ha as a direct means of identifying and quantifying commonly interpreted as evidence that rich clusters star formation within cluster galaxies from the central were, in the past, repositories for infalling field galaxies. core right out into the peripheral regions, it is possible The star formation in these field galaxies was enhanced to discriminate between the effects of different and/or suppressed as they encountered the high density mechanisms much more effectively. Fundamental to this cluster environment. A number of different mechanisms endeavour is the high throughput, extremely accurate have been postulated to modulate the star formation skyñsubtraction, and the 800x multiplex gain afforded within galaxies as they fall into a cluster: tidal interactions by LDSS++ when used in its novel ënodñandñshuffleí and merging with other galaxies; ramñpressure stripping mode. of the gas supply as the galaxy encounters the hot intrañ One cluster, AC114 at z = 0.32, has been observed to cluster medium; and galaxy ëharassmentí which arises date with spectra for 675 galaxies obtained through a from high speed encounters between galaxies. single mask. The results of analysing these spectra Which of these mechanisms are important has been have been quite startling, indicating that the cluster hard to determine observationally ó galaxy interactions environment strongly suppresses (rather than and merging is the only process that has been observed stimulates) star formation, and does so almost uniformly over the range of clusterñcentric radii explored here (0 ñ 2 Mpc). This is reflected in a low (15%) and essentially invariant detection rate of Hañemitting galaxies over the observed field (Figure 1). Furthermore, in none of the galaxies detected does the measured star

formation rate exceed 4 Msol per yr ó the pedestrian level seen in our own Milky Way galaxy (Figure 2).

The extent of this suppression is revealed quite dramatically by contrasting AC114ís Ha luminosity function with that of the ëfieldí at the same epoch (Figure 3). In the horizontal direction in which Ha luminosity and star formation rate is measured, the cluster function (solid and dotted lines) is seen to fall shortward of the field (dashed line) by more than an order of magnitude.

Figure 1. A combined B + I greyñscale image of the AC 114 field observed with LDSS++. The contours represent the surface density distribution of galaxies within and close to AC 114's E/SO colourñmagnitude sequence. Squares identify galaxies with definite Ha detections and circles identify galaxies with possible Ha identifications. The size of the field is 9.6 x 10.2 arcmin.

ANGLO-AUSTRALIAN OBSERVATORY page 6 NEWSLETTER AUGUST 2000 ASSOCIATED ABSORPTION IN RADIOñLOUD QUASARS HIGHLIGHTS SCIENCE Jo Baker (UC Berkeley) & R. W. Hunstead (U Sydney)

Absorption lines are seen frequently in the spectra of quasars. Many result from the quasar light passing though gas clouds between us and the distant quasar. Other absorption systems occur so close to the emission redshift of the quasar that they are probably associated with the quasar environment itself, although their precise origin is still unknown. These associated absorbers are too common to be due to intervening cosmologicallyñdistributed galaxies, but may arise either in galaxies clustered near quasars or in accelerated material close to the quasar nucleus in the hosts themselves. Figure 2. The star formation rates inferred from the observed Ha flux plotted as a function of projected local Narrow associated absorption lines are found galaxy density. Solid squares are definite detections and predominantly in radioñloud quasars, particularly open squares are possible detections. quasars with steep radio spectra (Foltz et al. 1986), so the phenomenon may be intimately related to the The initial indications from these very first observations physics of radio sources. These systems apparently are that the mechanism(s) responsible for suppressing differ from the broad absorption features seen star formation in clusters is widespread, extending well occasionally in quasars without strong radio emission. beyond the radii at which ramñpressure stripping is likely to be effective. More definitive conclusions, however, To study the properties of these associated absorbers must await observations of a larger sample of clusters in more detail, JCB and RWH have undertaken a at these redshifts. Expansion of the program in this comprehensive program of optical spectroscopy of direction is currently underway. quasars drawn from a complete lowñfrequencyñselected sample, the Molonglo Quasar Sample (MQS) (Kapahi et al. 1998). The majority of these observations were made at the AAT (e.g. Figure 1). Two main results have been found: (1) strong associated absorption is almost 0.1 1 10 100 never seen towards quasars with dominant radio cores where relativistic jets are beamed towards the observer; 1000 and (2) amongst steepñspectrum quasars, whose radio jets are not viewed pole on, and so are not dominated by viewing angle effects, associated absorption is seen much more frequently towards small (< 25 kpc) rather 100 than larger radio sources.

The first result implies that the absorbers occur only at large angles away from the jet axis. Such a geometry 10 may arise either if the absorbing gas originates in or near the dusty tori postulated in these radio sources (Barthel et al. 1997), or if the jet somehow clears out or

1 ionises the absorbing gas. That the absorption is 40 41 42 stronger towards intrinsically small radio sources suggests that the fraction of the source covered by absorbing material is greater when the radio sources Figure 3. A comparison of the Ha luminosity function measured for AC114 with that of field galaxies at a similar are small, and supposedly young (Readhead et al. 1996), redshift (dashed line) measured from the CFRS sample thus shedding some light on the growth of radio sources. by Tresse & Maddox (1998). The corresponding star formation rate is shown on the top x-axis. This cannot be due solely to orientation effects, because

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 7 AUGUST 2000 small and large steepñspectrum sources span a similar range of

CEC HIGHLIGHTS SCIENCE orientations. Combining these two pictures, a model can be proposed whereby the expanding radio lobes push aside and/or ionise the enriched HI clouds as they expand into the ISM and beyond.

Interestingly, the absorption systems we have found towards CSS quasars are remarkably similar to those seen towards highñredshift radio galaxies (HZRGs), notably the strong Lya absorption (Rˆttgering et al. 1995). This is illustrated in Figure 2 by the striking comparison of the Lya profiles of a CSS quasar from the MQS and a MRC HZRG, both at z = 2.9. Based on these similarities, many small HZRGs may in fact be misaligned CSS quasars with their broadñline regions hidden by a dusty torus. This is also consistent with the identification of polarised scattered Figure 1. (Top) AAT spectrum of MQS 1114ñ220 (z = 2.282, BJ = 20.2) at a light from ëhidden quasarsí in HZRGs. resolution of 5≈ FWHM. The associated absorption system is clearly In HZRGs too, a trend has been noted identifiable: note the absence of Lya emission (expected at 3990≈) and the IV em strong Lya and C absorption lines at zabs. The obliteration of the whole for strong Lya absorption to be seen Lya emission line (and underlying continuum) implies that the absorber preferentially towards sources of small contains a large column density of HI and, probably, dust. (Bottom) At higher IV resolution the C absorption feature (zabs ~ 2.295) shows at least three linear size and those with bent and velocity components, the strongest lying about 1200 km/s redward of the line peak. Complex velocity structure is indicated, e.g. a disturbed medium knotty morphologies (van Ojik et al. of discrete clouds possibly undergoing infall. 1997; Barthel & Miley 1988).

To test whether the preponderance of HI absorption in small sources is a consequence of high redshift or small source size, JCB and RWH have been awarded HST time to search for associated absorption in lowñredshift quasars.

References

Foltz et al. 1986. ApJ, 307, 504 Kapahi et al. 1998. ApJS, 118, 327 Barthel et al. 1997. ASP Conf. Series, 128, 48 Readhead et al. 1996. ApJ, 460, 634 Rˆttgering et al. 1995. MNRAS, 277, 389 van Ojik et al. 1997. A&A, 317, 358 Barthel & Miley 1988. Nature, 333, 319

Figure 2: Overlaid spectra (1≈ resolution) of a z = 2.9 CSS quasar MRC 0246ñ213 (dotted line) and the highñredshift radio galaxy MRC 0943ñ242 (from Rˆttgering et al. 1995) also at z = 2.9 (solid line). Both spectra have been shifted to the rest frame of the strong Lya absorption line. The radio galaxy spectrum, which has essentially no continuum, has been shifted upwards to match the quasar continuum level, and then scaled to the peak of the Lya emission line.

ANGLO-AUSTRALIAN OBSERVATORY page 8 NEWSLETTER AUGUST 2000 If one adopts the average expansion velocity found for THE LARGEST PNE KNOWN? this object of about 43 km/s at Ha (Lopez et al. 1991) Quentin Parker (ROE) then this would imply that the outer lobes were ejected HIGHLIGHTS SCIENCE 140,000 years ago. This compares with a lifetime of a The bright bi-polar nebula NGC 2899 (PN G277.1ñ03.8) few tens of thousands of years for typical PNe. However, is thought to be an evolved type I high excitation PN since statistical distance estimates depend on the (class 7/8) with a massive core exhibiting split lines measured angular extent of the nebula, it is more likely right across the image and has a published optical major that all previous statistical distance estimates are highly axis of about 2.6 arcmin (Lopez et al. 1991, A&A, 241, inaccurate as they were based only on the central core 526). A distance estimate of 1.03 Kpc is obtained from image. If we adopt 20000 yr as a nominal lifetime for averaging the 8 published statistical distance estimates this object and the new angular size of 21.5 arcmin taken from Acker et al. (1992). then a distance of 112 pc is obtained. This would make NGC 2899 the closest PN to the Sun! The two new features were found during detailed visual scrutiny of a UKST Ha survey exposure. At first the two Clearly further investigation of these possible faint nebulae were identified as separate new PNe associations is required as they may have serious candidates until it was realised that these features lie implications for our understanding of stellar evolution. almost exactly 10.7 arcmin either side of the centre of FLAIR-II spectroscopy of the outer lobes and central NGC 2899 in a straight line straight through the core of nebula have recently been obtained which reveal that the object and along the major axis of the bi-polar the brighter SE lobe has a very similar spectrum to that morphology. This gives it a possible angular E-W extent of the core nebula, i.e. [NII] very much stronger than of 21.5 arcmin. Only the Helix nebula, the closest known Ha. The fainter NW lobe only reveals [NII] as the FLAIR-II PN to the Sun at 140 pc, has a larger projected angular spectrum is much weaker. The strong spectral similarity size at Ha (up to a degree). strengthens the likelihood of a true association.

The symmetry of the central image of NGC 2899 Discoveries of faint outer nebular features are becoming indicates that the bi-polar lobes of NGC 2899 are well more common as bright PNe are studied in more detail aligned on the plane of the sky. This tallies with the and with deeper imaging. They are potentially important equidistant lobes if uniform ejection velocity and ISM to tackle the problem of PN ëmissing massí; to study density is assumed. The central nebula image and these the interaction of previous episodes of ejecta with the outer lobes are shown in Figure 1 while a closer look at ISM; to determine the interval between such episodes; these two faint lobes is given in the insets to Figure 1. It and to improve our understanding of stellar evolution. must be stressed that these observations are very Faint new outer features (arcs, blobs, ansae and shells) preliminary and may represent chance co-incidence. have been found around many of the published bright However, if these two lobes do indeed represent an PN examined on the deep wideñfield Ha survey images. earlier episode of ejecta, these observations would imply Such objects are the subject of a follow-up project of a physical extent of 6.2 pc. Dopita, Hua and Parker.

Figure 1. Image of NGC2899 and outer lobes taken from Ha survey exposure number HA17965 (survey field H220). The figure is approx 28 x 14 arcmin in size and NE is to the top left. Insets show expanded views of the brighter SE lobe (left) and fainter NW lobe (right). The lobes are both approx 10.7 arcmin from the centre of NGC 7899.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 9 AUGUST 2000 instrument changes; and tendering for the supply and WHAT'S HAPPENING AT SITE? installation of a jib crane and hoist to assist with Chris McCowage configuration of the aluminising tank. Fire fighting equipment has been updated. We continue to set There have been many developments in infrastructure. stringent rules on access to the telescope, particularly A major project is in progress to replace the drainage at night, and I'd like to remind visiting astronomers of SITE system. The new system will be far more friendly to our these requirements. environment. The purchase of a new efficient, low emission, lpg-fired boiler is also helping to "green" the Unfortunately, site security has become an issue of late, NEWS site, as is the new nitrogen gas supply (p13). The new with a flurry of break-ins and minor crime in town which boiler and nitrogen plant will also provide significant has extended as far as the UKST. Please ensure you savings in operational costs. An AAT and UKST systems lock vehicles on the mountain and be especially careful urgent and non-urgent alarm system has been designed to keep the telescopes locked. A review of AAO building and installed. The system includes a Technician call security is in progress. system (p12). Work is underway preparing the UKST We are in the middle of a major change in instrumentation infrastructure for 6dF and installing additional cable trays at both telescopes, with the decommissioning of at the AAT to continue the roll out of the upgrade to the photography at the AAT (p 20) and Flair II at the UKST networking. (p 19). The arrival and commissioning of WFI at the AAT Safety remains an important issue at site. A new (Back Page) marks the start of another hectic year of mechanical handling aid has been installed at the UKST new instruments, especially IRIS 2 and 6dF. Other to assist with loading plate holders, including the new projects to follow include the installation of the UKST 6dF and Tokyo CCD camera. Other O&H projects Comsoft PC-TCS control system and the Tokyo CCD include the purchase of a small electric tractor to reduce camera. And before these instruments see a photon, material-handling hazards during aluminising and new projects are being proposed (see AAW on p 15). Looks like we'll be busy for a while yet!

PROTECTING THE SITE Shire Council, Fred Watson of AAO, Reg Wilson, an independent lighting consultant acting for the Fred Watson observatory, and John Whitehead, former Shire Engineer, who was involved with the original REP. The unpolluted skies that make Siding Spring one of the darkest observing sites in the world are protected Much of the first meeting in early August revolved around by a legal instrument called the Orana Regional the strategic approach to the revision, but considerable Environmental Plan No.1 (REP). It covers an area 100 km progress was made. Issues discussed included the in radius centred on the AAT dome, and it is administered necessary revisions to the DCP as a precursor to the primarily by the Coonabarabran Shire Council. The revised REP, light shielding, sports ground lighting, practical manifestation of this is another document called consultation with outside bodies, the revision of distance the Coonabarabran Shire Development Control Plan No.2, thresholds, and the question of whether the area coverage or DCP. The REP has now been in force for about a of the REP needs to be increased to take in other decade, and it was always the intention that it would be growing population centres. An issue that is seen as revised on about this timescale. The need for revision vitally important is the development of an education has recently been highlighted by a number of factors, policy on effective lighting and dark skies. This must including technological change in the lighting industry, target not only consumers and local authorities, but the introduction of new Australian Standards for lighting, lighting contractors and wholesalers. There is also and a realization at the grass roots level that the DCP the possibility of devising a rating system for is rather hard to interpret and subject to environmentallyñfriendly lights, along the lines of the misunderstanding ó potentially allowing undesirable ìIDA tickî in the USA, or a standards mark. developments to pass through the net. Over the coming months, the Working Party will be Late in 1999, the Council formally approved a suggestion seeking to advance the cause of skyñglow reduction in by Jeremy Mould (Director of RSAA) that the REP should the REP area as vigorously as possible while be revised. A Working Party has been set up to define acknowledging that there are limits to what can be the revision requirements, with members Peter Downes, achieved. This pragmatic approach should guarantee Western Regional Director of the Department of Urban the viability of Siding Spring as a dark site for decades Affairs and Planning, Greg Meyers, of Coonabarabran to come.

ANGLO-AUSTRALIAN OBSERVATORY page 10 NEWSLETTER AUGUST 2000 The cooling system is installed on the 2nd floor of the IMPROVING AAT SEEING AAT beside the hydrostatic oil pumps. It consists of a Jonathan Pogson 20 kW refrigeration plant which chills a 1600 litre reservoir of water/glycol mix (70:30) to ñ5oC. and then circulates The Seeing Project is an ongoing effort to minimise the the cold fluid through a highly efficient plate type heat seeing (or image degradation) at the AAT. Main areas of exchanger to pre-cool the oil before it in turn is pumped I NEWS W E N E SIT interest are minimising local sources of heat such as at high pressure to the telescope support pads. the hydrostatic oil system, and improving the AATís Ultimately the heat is drawn out of the building via a response to changing weather conditions. large air-conditioning duct and then exhausted at the northern end of the utilities building. The cooling plant Hydrostatic Oil Cooling on the AAT operates under the control of an Innotech Genesis II Every night for 25 years the AATís hydrostatic oil system PLC which monitors temperature and humidity conditions has poured about 8kW of energy directly into the inside and outside the dome and is configured to o horseshoe and north journal bearings as an unwanted maintain the oil pads at dome air temperature or 2 C by-product of the high pressure required to float a 260 above dew point ó whichever is greater. The Gen.II PLC tonne telescope on a film of oil. allows us to remotely monitor, reconfigure, analyse and log all aspects of plant operation, system performance Every night the effect of that 8kW was to directly warm and met conditions. The oil itself was required to be the oil pads, horseshoe, north journal bearings, and of changed to a type (T46) more suitable for operation at course, the oil itself. These effects were dramatically low temperatures. seen when Mitsubishi briefly loaned us an infra-red camera which enabled us to view the telescope at a Mirror Cooling or Dome Air-Conditioning? wavelength of 5 mm. By midnight a thermal equilibrium A second project which has been on hold is the cooling had been reached and the entire AAT horseshoe bearing of the AAT mirror. Unfortunately, there are major was seen to ìglowî in the dark - for the oil pads were o difficulties involved in cooling the mirror. The mirror is a typically maintained at 10 C above the ambient dome 600 mm thick 16 tonne block of cervit mounted in an temperature. As equilibrium was approached, rising equatorial telescope installed on a relatively humid site, thermals would have been blown around and above the factors which all combine very effectively to frustrate telescope and very likely have been responsible for the any simple solution. Merely cooling a 16 tonne block of seeing deteriorating during the night. Even worse, if the cervit isnít really a problem on its own, providing you telescope support system had been running during the donít mind dew forming on its surface. Mounting a day for engineering purposes the telescope would have cooling system on the telescope isnít a problem either, been ìpre-warmedî so that observing would commence o providing you donít want to move the telescope. Of with the oil pads as much as 15 C above ambient. course, humidity wouldnít be a problem if you didnít But now ó after 25 years ó an oil cooling system is mind a warm mirror! And assuming that these and other finally operating, and we have completely removed difficulties were resolved, the idea of pre-cooling the the most significant source of heat within the dome. mirror to the minimum night temperature sounds fine if The success of the system is shown in Figure 1, showing you know what temperature to expect, which we donít. the difference between the oil pad temperature and the While thrashing possible solutions out, it became dome air over 6 days before and after oil cooling was apparent that the single problem which fundamentally operational. Average temperature differences dropped o o challenged every option was humidity. Humidity levels from 6.9 C to 0.5 C.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 11 AUGUST 2000 at the AAT are high enough often enough that unless of next night temperature, windspeed, humidity and we could reduce humidity levels in the dome, cooling dewpoint. These data will enable an automatic system the primary mirror would significantly increase lost to optimise dome conditions for observing. observing time through dew on the mirror or inside the cooling ducts and associated equipment which would NEW ATAC DEADLINES drip all over the mirror as it was tipped around the sky.

SITE At its meeting on June 6 2000 ATAC decided to In hindsight the answer was obvious ó our first priority bring its semester application deadlines into line must be to reduce humidity, and the simplest way to with those of PATT, i.e. the last day of September NEWS reduce humidity is to air-condition the dome. By air and March, for semesters A and B respectively. conditioning the dome we could have full control over This means that the next proposal deadline (for humidity levels and thus eliminate the risk of dewing Semester 01A) will be midnight AEST on Saturday, the mirror. Moreover it allows us to pre-cool everything September 30 2000. The AAO will begin in the dome, including the telescope and the primary accepting applications via the usual Web-based mirror, with a view to the entire dome environment being submission system from 1 September. prepared for a predicted night time temperature. This is particularly valuable because we believe that the mixing that occurs between dome air and outside air at the COUDE UPDATE windscreen aperture is the major contributor to poor Ray Stathakis & Stuart Ryder seeing. And by pre-cooling the dome we are going some way toward pre-cooling the mirror. If carefully designed, Earlier in the year UHRF was found to have significantly it should be able to run during observing to enable us to poor throughput. The problem was traced to a misaligned protect against humidity even with an open dome. It lens in the image slicer. The system has been realigned, should allow us to exactly match unexpected or variable and is now operating at optimum efficiency. Test outside air temperatures instead of always following observations in March of two standard stars gave 122 behind. It can be installed without compromising our Hz/0.01≈ in 1.3 arcsec seeing for a star with AB = 3.0 existing dome ventilation system. Finally, if desired, the magnitudes at NaD1 (5893≈) ó comparable to the value dome air can be heated. of 100 Hz/0.01≈ in 1.8 arcsec seeing measured in 1994.

Air-conditioning the AAT dome is hardly a new idea, but UHRF can deliver resolutions of 3e5, 6e5 and 1e6 through it has long been ignored because it is assumed to be the image slicer. An alternative setup is to observe very expensive. However in our case the AAT was directly through a 0.6 arcsec slit at 3e5 which results in originally designed to be air-conditioned and most of 100,000 resolution. The slit has 4 ñ 5 times the efficiency the expensive infrastructure is already in place. Few of the slicer, depending on the seeing. people would realise how much space in the AAT dome is taken up by ductwork and plenum chambers, and An updated version of the UCLES and UHRF user how many holes and cutouts through floors and ceilings manual is now available online at http://www.aao.gov.au/ are already in place, only hidden behind insulation. The local/www/UHRF/manual/coude_um25_3.html. main air-conditioning plant was installed with Comments and suggestions are welcome to considerable excess capacity, and is easily powerful [email protected]. Both UCLES and UHRF are enough to cool the dome. Even the pipework is in place, offered in service mode for projects requiring up to three now capped off and waiting to be connected and the hours integration. Recent successful service nights for electrical submain cables are currently used by the main both instruments have almost emptied the queue, so fans. In short, the AAT dome is begging to be air- send us those requests! conditioned! ARE YOU BEING SERVED? In view of this we are currently engaging the services of a consultant to design a system optimised for our needs, Allan Lane provide cost estimates, and, assuming the project is approved, to control the project in a professional and It will now be harder for afternoon technicians and night cost-effective manner using a mix of contractors and assistants to hide out, with the installation of a Technician site staff. Our estimations to date suggest that the cost Call button in the control room. The observer needs only of this project can be kept close to $200K. press the button (located under the weather PC near the noticeboard) and an alarm will notify the on-duty We are also negotiating with the Met Bureau with a technician or night assistant that he is needed. This view to obtaining a specialized met prediction service should be particularly useful on weekends and during for Siding Spring in order to give us improved estimates cloudy nights (but use with discretion, please).

ANGLO-AUSTRALIAN OBSERVATORY page 12 NEWSLETTER AUGUST 2000 slewing the rotator to THE ACQUISITION AND GUIDING position inside the UNIT UPGRADE readout time of a CCD. We have received Darren Stafford delivery of the new rotator motor and

The acquisition and guiding (A&G) unit is located just S W E N E SIT controller. Controller below the primary mirror of the AAT. Cassegrain software and bench instruments are bolted to its base and it is controlled tests are almost by the interdata telescope control system. The A&G finished. After a unit has provided observers with facilities to acquire fields suitable absolute and guide off axis for 25 years. The fact that the unit is encoder is found we still in regular operation indicates the soundness of the can install and original design and its implementation. commission the new A project is well underway to modernise the A&G unit rotator system. to improve observing efficiency and reliability. The The new acquisition camera (see previous issues) is existing electronics are being replaced with motors and now in regular use. Most of guide probe 1 has been controllers from Baldor, a PC and some ìin houseî built removed from the A&G unit and temporarily replaced electronics. The new A&G unit will have its own stand- with a wooden mock up, allowing work to proceed without alone control system, so it will be independent of the affecting telescope operations. The mechanical section interdata. is now fitting the 6 new electric motors to the probe. Currently the rotator takes six minutes per revolution. The installation of the new CCD guiding camera is soon Hours of observing can be lost each night that requires to follow. Once the modernisation of probe one has been many changes in rotator position. With new motors and fully commissioned we will modernise probe two, electronics we can reduce this overhead to zero by currently used for spectropolarimetry.

flow rate of 4 litres/min. Higher short term flow rates are NEW NITROGEN GAS SUPPLY possible from the 330 litre external reservoir. When ARRANGEMENT FOR THE AAT there is no demand for nitrogen the generator tops up Frank Freeman & Wayne Clarke the storage reservoir and then shuts down until flow is required again. For some years we have had a reticulation system With the reduction in cylinder costs and associated providing a gaseous nitrogen distribution around the AAT building and to the telescope. This has traditionally been handling, we hope that the generator will have paid for itself after five years and then provide us with ìfreeî high supplied by cylinders which have to be transported between Coonabarabran and the mountain. Besides purity nitrogen during the rest of its lifetime. requiring a lot of heavy manual handling, the cost of cylinder hire and gas purchase for this facility is a relatively expensive ongoing charge. To enhance the safety of staff and reduce the costs associated with the provision of this gas supply, a nitrogen generator has been installed at the ground floor. The principle of operation is to compress air through sorb columns that remove most of the other constituents and then pass the nitrogen to storage for further distribution.

The generator is plumbed in so that the system can be isolated for maintenance, hopefully only required at six- monthly and yearly intervals. There will still be nine bottles of our old nitrogen supply on standby, six for the telescope and three for the building. The generator specification is to supply nitrogen gas with a purity >99.995% at a pressure of 500kPa (75psi), and with a

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 13 AUGUST 2000 which replace the original stepper motors. Filter PENGUIN'S changing and guider focus use DC motors. Encoder PROGRESS interfacing is planned to be via a CAN bus interface Chris McCowage using a supplied Linux driver. The application will run under the DRAMA environment. The AAO has used many of the GNU

SITE Tokyo Camera development tools as well as other open source applications for a The Tokyo camera, which has been described in an

NEWS number of years. We thought that our readers may earlier newsletter, is a collaboration between Tokyo appreciate a review of the current and planned use of University and Bruce Peterson of RSAA, ANU. The GNU-Linux at the AAT. GNU-Linux rarely seems to be camera will provide CCD imaging for the Schmidt introduced into an organisation as a conscious decision Telescope. This drift scanning CCD system uses an at a high level. The more typical mode is one of osmosis. array of CCDs controlled by an Apogee camera and Generally it seems to appear on the desktops of a few controller using commercially developed Linux drivers, technically inclined aficionados. Then the stability, loadable kernel modules actually, and camera control networking, good performance on modest hardware and software developed by the author of the acquisition availability of open source development tools and camera software. The camera is mounted in a modified libraries lead to the first experimentation. UKST plate holder. PFU The first application at the telescope was the development of an engineering test bed system used Epping software engineer, Serge Ivanoff, has developed for debugging the 2dF power supply and 2dF auxiliary the application to control the new AAT Prime Focus bus digital IO hardware. Darren Stafford developed the Unit. The PFU uses a Tech-80 TE 5650A motion control application which used the parallel port as digital IO to card to operate DC motors and pneumatics for the large generate address and data on the auxiliary bus. The shutter and filter wheel. Serge developed the TE-5650A original system was built on a Slackware1.1.59 kernel device driver and application operating under the AAOís based system. The preferred distribution is now Redhat. DRAMA environment. A Tk/tcl GUI provides an LINDAS represented a more ambitious project by engineering interface. The PFU Linux/Intel single board Darren. The LINux Data Acquisition System enabled cpu also employs a serially linked bar code scanner to engineering control of the AAO CCD Controllers to identify filter holders. acquire data from optical CCDs and IRIS. The initial digital IO was via the parallel port, but soon evolved 6dF robot into a purpose built digital IO cardwith on board FIFO 6dF represents the most ambitious project using GNU- to improve performance at higher read out rates. A Tk/ Linux. The new fibre positioning robot for the Schmidt tcl interface GUI front ends the data acquisition Telescope employs an Intel/Linux system to control application with the astronomical data reduction system serially linked Kollmorgen Servo Star motion controller/ IRAF installed for on line data display and reduction. amplifiers to operate the R and theta axis. Digital IO provides operation of the pneumatics. Images from the AAT Cassegrain Acquisition & Guidance Upgrade gripper camera are captured on a frame grabber and The new cassegrain acquisition camera currently uses centroided. Epping software engineer Niki Frampton has a headless singleboard computer on an ISA passive developed the application to control the robot as well as backplane to accommodate the Apogee AP-8ISA CCD migration of various components of the 2dF software to controller. The AP-8 camera uses a SiTe 1024x1024 GNU-Linux. thinned thermo-electrically cooled CCD. Linux drivers DRAMA and a camera control and image display application were purchased to operate the camera. The control, The AAOís DRAMA environment has been developed display and integration of the camera will be developed by Tony Farrell, Keith Shortridge and Jeremy Bailey. to operate under the AAOís DRAMA environment and This and other applications have been ported to GNU- SkyCat. Linux by the team. Thanks to the efforts of the Open Source movement and the talents of the AAO and AAT The upgrade of the AAT Acquisition & Guidance unit staff, observers can plan a 2dF configuration, reduce will use another Intel/GNU-Linux ISA single board data using FIGARO, tweak their plots with pgperl by computer to control serially linked (RS-485) Baldor MINT Karl Glazebrook all without leaving the comfort of their drives. These controllers drive brushless AC motors Xfree86/GNU-Linux personal computer.

ANGLO-AUSTRALIAN OBSERVATORY page 14 NEWSLETTER AUGUST 2000 AAW David Lee

Many readers may have seen the recent document: ìPartnership in Innovation: The AAO of the Futureî which presents the AAO strategic scientific and SITE instrumentation plan for the next decade. Much of the AATís future scientific focus will be on the development NEWS of wide-field survey type projects that are currently so successful. An example is a spectroscopic follow up to the VISTA imaging survey. To make the next major step in survey astronomy, the AAO would need to embark on a programme that extends at least a factor of 10 fainter than the SLOAN digital sky survey. The spectrographs will no longer be mounted on the To facilitate spectroscopic surveys to g~22 mag and 2dF top end ring. A temperature and vibration stabilised beyond will require both the throughput and stability of bench mount will be used resulting in significantly 2dF to be enhanced. To achieve this an innovative new improved calibration efficiencies. This is vital for accurate spectrograph for 2dF is proposed: the AAW project. background subtraction to reach the faintest possible AAW will realise a factor of 3 efficiency gain over the magnitude limits. current 2dF system by utilising a number of system In addition to multiple object astronomy AAW will provide enhancements. Next generation CCDs will be used to a single object integral field spectroscopy capability via provide increased efficiency. The larger detector area a SPIRAL type fibre feed. A 4000 element integral field will allow charge shuffling and decrease fibre cross talk. unit is envisioned which will be mounted on the 90 The current 2dF fibres may be replaced with the new degree position of the 2dF tumbler mechanism. Such a Heraeus STU fibres to increase throughput. Also format would permit R > 12,000 IFU spectroscopy over improved termination and alignment techniques will be a ~2000 square arcsecond field of view. The AAW IFU used. system would have an efficiency comparable to an Completely new spectrographs will be developed optimised low dispersion slit spectrograph. It is expected incorporating the latest in technology. The fully that the AAW IFU system will provide much of the transmissive optics will use Solgel anti-reflection functionality currently provided by the RGO spectrograph. coatings providing a ~ 35% gain in transmission. The There is some concern that an IFU can provide accurate efficiency will be further improved, up to ~ 50%, by the spectrophotometry, allow spectropolarimetry, and provide use of Volume Phase Holographic (VPH) gratings. An UV coverage. The spectrophotometric performance of overall efficiency gain of a factor of 2.5 ñ 3 is expected. the SPIRAL system is currently under investigation but initial results indicate spectrophotometry can be done to an accuracy of 1%. Implementation of spectropolarimetry is expected to be straightforward with AAW via the use of a polarisation module upstream of the IFU input optics. Optical fibres can be used in the ultrañviolet region if the appropriate type of fibre is used i.e. High OH Silica. A comparison of the transmission of an optical fibre versus a 4 mirror system, such as that used in the AATís coude mirror train, is shown in Figure 1. Fibres only become less efficient for wavelengths shorter than ~ 350 nm. However, it should be remembered that there are no slit losses associated with using an IFU as there are with a longñslit.

The AAO is currently initiating a conceptual design study for the AAW system. This will investigate the optical, mechanical, electronic and software design of the Figure 1: Plot of transmission of STU and High OH optical fibres compared with four aluminium reflections. instrument.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 15 AUGUST 2000 Charge Shuffling IMAGING POLARIMETRY WITH TAURUS The new feature we have recently introduced is the use Jeremy Bailey and Lucyna Kedziora- of CCD charge shuffling to modulate the polarization. Chudczer Charge shuffling has been used successfully at the AAO in conjunction with Taurus etalon scanning, and in

SITE Introduction conjunction with telescope nodding for LDSS++. Our new mode of operation allows charge shuffling to be We have recently commissioned a new mode of synchronized with motion of the half-wave plate in the NEWS operation for Taurus as an imaging polarimeter, used in polarimeter. conjunction with CCD charge shuffling. Taurus was fitted with polarimetry optics some years ago. This system, A typical polarimetry charge shuffling sequence allows the Faint Object Polarimeter (FOP), was developed by cycling through four half-wave plate angles (0, 22.5, 45, Mark Cropper. In the past the FOP has been normally 67.5 degrees), with exposures of about 10 seconds in used for studies of timeñvariable polarization in stellar each position, and the cycle repeated as many times objects. as are required to get a suitable total exposure time. The single CCD frame read out at the end of the The polarimeter system uses a Wollaston prism sequence contains eight images of the field (the two mounted in the etalon wheel of Taurus. It can thus be Wollaston images at each of the four half-wave plate used in conjunction with broad band and narrow band positions). This requires the MITLL2 or MITLL3 CCDs. filters, but not with the Taurus TTF or other etalons. The The Tektronix CCD is not large enough to allow for four Wollaston prism gives a double image of a source on shuffle positions of this size. the CCD in two orthogonal polarization states. It is used in conjunction with a slot mask in the focal plane which In this way a complete observation of linear polarization prevents the two polarization images overlapping. The and position angle is obtained from a single CCD frame. third component of the system is a polarimeter module The data can be reduced using the Starlink POLPACK in the A&G unit which is used to rotate a half-wave plate. package written by Tim Gledhill and David Berry. The polarimeter module is the same one used for The charge shuffling sequence can be set up using the spectropolarimetry with the RGO spectrograph and was user interface shown in Figure 1, and then executed built at the University of Hertfordshire. with a single command from the OBSERVER software. For polarimetry Taurus must be used at the É/15 This interface also supports standard nod-and-shuffle cassegrain focus, as the Wollaston prism is not large operation, as well as combined polarimetry nodding enough to accept the É/8 beam. The field of view is modes, which use a charge shuffling sequence with two about 26 x 100 arcsec, set by the width of the slot wave plate positions and two telescope positions for mask and the size of the half-wave plate. improved sky subtraction on extended sources. Example Observation

As an example of the use of the system we show an observation of the central part of the reflection nebula NGC 6729 illuminated by the pre-main-sequence star R CrA. The raw CCD data is shown in Figure 2 and is a single CCD frame of duration less than four minutes. It shows the eight images of the source as described above. To reduce the data it was split into four images for the four half-wave plate positions and then reduced using the Starlink POLPACK package to give the data shown in Figure 3 which shows polarization vectors overlaid on the intensity image. The data shows the circular pattern of vectors around the illuminating source expected for a reflection nebula.

Other tests during the commissioning run have used observations of polarized and unpolarized standard stars to verify that we can obtain a polarization accuracy of Figure 1. User interface used to set up polarimetry charge about 0.1% or better, and that the instrumental shuffling sequences. polarization is small.

ANGLO-AUSTRALIAN OBSERVATORY page 16 NEWSLETTER AUGUST 2000 Switching between linear and circular polarimetry requires changing the wave-plate inside the polarimeter module which is not easily accessible during observations. Normally therefore the system configuration cannot be changed from linear to circular observations during the night. SITE Sensitivity

We are still establishing accurate sensitivity figures for NEWS the polarimeter. However, since the throughput of the system is high a rough guide can be obtained using the direct imaging S/N calculator on the AAO web pages (http://www.aao.gov.au/cgi-bin/pfcalc.pl). Use the setting for prime É/3.3 which is closest to É/4 at Taurus. To get polarization accuracy of 1% requires S/N of 100, 0.1% needs S/N of 1000. Then double the exposure times returned.

In this way we find that polarization of 0.1% can be measured in about 1 minute at R=15, and in about 20 minutes at R=18. Figure 2. A raw CCD frame from an observation of the reflection nebula NGC 6729. This shows eight images of the field, the pair of images from the Wollaston prism at Status each of four half-wave plate positions. The total time for the observation was under four minutes. The new polarimetry system will be available as a common user facility for semester 01A. On-line documentation can be found on the web (http:// Circular Polarimetry www.aao.gov.au/local/www/taurus/taurus_pol.html). If you It is also possible to do circular polarimetry with the have any questions that arenít answered there contact system by using a quarter-wave plate in place of the Jeremy Bailey ([email protected]). half-wave plate. However, with the current system there Future Developments is a leakage of linear polarization into circular polarization which must be corrected for if the source is A new polarimeter module is now being designed, also linearly polarized. One way to do this is to rotate primarily for use with IRIS 2. However, it will also be the instrument through 90 degrees and repeat the useable with Taurus and will provide wider fields, easy observation which reverses the sign of the linear Stokes switching between linear and circular modes, and will parameters. However, this is inconvenient for extended remove the linear to circular leakage problem by using sources because of the rectangular field of view. a system with both half and quarter-wave plates.

Figure 3. Polarization map of NGC 6729 obtained from the single CCD frame in Figure 2, after reduction with the Starlink POLPACK package. Polarization vectors binned over 6 CCD pixels (1.2 arcsec) are overlaid on the intensity image.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 17 AUGUST 2000 be made generally available as part of the staged onñline THE UKST H-ALPHA SURVEY ó survey release from 2001, requests for pre-release copies AN UPDATE of data on a field-by-field basis can be made directly to Quentin Parker, WFAU, ROE the SuperCOSMOS group if anyone has an interest in specific fields.

SITENEWS The AAO/UKST is undertaking an Ha survey of the High priority for the survey has recently been agreed for Southern Galactic Plane and Magellanic Clouds using the Ha survey in the SuperCOSMOS scanning program a high quality, 1% singleñelement interference filter such that the timescale between the end of the survey centred near Ha (6590≈) and using high resolution Tech- at the telescope and the scanning of the last film by Pan film as detector. All 3 hour Ha exposures have SuperCOSMOS will be 3 months or less. Details of all associated and usually contemporaneous broadñband the Ha/SR film pairs scanned to date can be found at short red ëSRí exposures (also on Tech-Pan) which are http://www.roe.ac.uk/cosmos/Halpha.html. well matched for depth to continuum images on the Ha films. Community questionnaire

An unrivalled map of gaseous emission is being A www based community questionnaire was issued in produced in terms of the combined coverage, resolution April which was designed to address factors such as and sensitivity. The survey comprises 233 fields on non- the need for and interest in the survey and the form and standard 4 degree field centres covering the whole of scope of data access desired. Between April and early the Southern Galactic Plane to |b| = 10 plus an additional May 174 responses were received from the world 40 fields in and around the Magellanic Clouds. A crucial community with an approximately even split between point is that the survey is non-proprietorial. responses from the USA; UK/AUS/Europe; and the rest of the world or anonymous. The results present a Current survey status compelling case to support the provision of suitable This survey is the last new UKST photographic survey onñline access to the AAO/UKST Ha survey. There is being undertaken and since July 1997 accounts for clear and widely based community interest in providing approximately 40% of available UKST time. As of July this survey as a general astronomical resource. Full 2000 the main survey is 70% complete to A-grade and details and results from the questionnaire can be found 90% complete to B-grade while the MC fields are 42% as a link from the new survey www pages. complete to A-grade and 87% to B-grade. These gradings The proposed survey access model now reflect the standard survey quality-control grades that have recently been applied to all survey exposures In early June the UK WideñField Astronomy Panel by Malc Hartley (AAO) and Sue Tritton (WideñField (WFAP) endorsed the fundamental WFAU Astronomy Unit (WFAU) in Edinburgh). This should recommendations for the management and provision of ensure that the homogeneity and overall quality of the the survey data products set out in a series of reports survey material upholds the best traditions of previous tabled at the meeting. Firstly, an updated science case UKST atlases. The big difference here, though, is that was submitted to re-establish the merits of the on-going the principal form of dissemination to the community survey, to reflect the current areas of exploitation, to will be via the www and direct access to digital data highlight the broad interests of the larger community (see below). and hence to justify the planned level of WFAU involvement. A detailed report was also submitted on Although the Galactic Plane season is finished for the the effort and storage requirements necessary to provide current semester there is a good chance that by this an appropriate level of support and functionality for survey time next year the survey will be complete. A map of access. This should be commensurate with expressed current survey progress can be found in a link from the community interest and should protect the unique newly updated Ha survey www pages at aspects of the survey in a demonstrably useful and http://www.roe.ac.uk/wfau/halpha/halpha.html. easily accessible product. SuperCOSMOS scanning As a result the following survey model has been All survey exposures are shipped in regular instalments endorsed: to the WFAU at the ROE which has accepted prime ï Ha/SR data stored online on a field by field basis responsibility for disseminating the survey data to the and accessed via a suitable www interface with a community. SuperCOSMOS is routinely scanning the pixel data access limit of 15 arcmin (same as SGC) Ha/SR exposure A-grades and has now scanned 73 ï Data stored initially on a DVD-RAM jukebox. Ha/SR pairs as of July 2000. Although these data will ï a 5ñ10x blocked-down survey version (100 ñ200

ANGLO-AUSTRALIAN OBSERVATORY page 18 NEWSLETTER AUGUST 2000 Gbyte) stored on RAID allowing large areas to be surveys become possible offering excellent retrieved ( say 2 x 2 deg regions ó 23 Mbyte) but opportunities for useful community exploitation still field by field ï accessibility is expected to equate to enhanced ï 30 arcsec resolution 30 Mbyte FITS files of each community interest and use field could be put on-line to allow large areas to be ï provision of field by field access simplifies the overlap viewed/mosaiced together prior to selection of problem SITENEWS smaller areas at full resolution It is anticipated that a full online atlas could be available ï calibration data provided for each field separately; by March 2002 but with the likely release of limited calibration itself done by the user contiguous areas in stages from early 2001. ï IAM data also available field by field but with the ability to create seamless catalogues over any New results number of fields. IAM data also explicitly tied to A variety of different projects are underway to exploit extracted pixel data (15 arcmin limit) as for the SGC the survey material and a regular stream of interesting ï eventual provision of the equivalent I-band survey discoveries and comparisons is being made, e.g. several data. This would be matched to the Ha/SR at query new and rare-type Wolf-Rayet central stars from time as querying done by celestial co-ordinates spectroscopic follow-up of the large number of new PNe (could be part of a second release) discoveries (~700 found so far). See AAO Newsletter ï initially no matching of field-field background 93 and Morgan, Parker & Russeil, MNRAS submitted. variations (i.e. to avoid ëpatchwork quiltí effect) but Other projects include discovery of several new optical again could be part of second release. supernova remnants (Walker et al., PASA, submitted), new Herbig-Haro objects in Orion (Mader et al., 1999. Model Advantages MNRAS, 310, 331) and interesting comparisons ï on-line provision means immediate world-wide between the Ha survey and MSX 8 mm and MGPS2 accessibility to the survey products (MOST) 843 Mhz data (McIntyre et al., private ï comparisons with other on-line catalogues and communication). See also p 9 for a recent discovery.

GOODBYE FLAIR GLASS-PLATE SURVEYS NEAR COMPLETION Fred Watson

FLAIR has been the name of the UK The raison d'Ítre for the UKST during the 1970s and 1980s Schmidtís manuallyñconfigured multiñfibre was the compilation of a full hemisphere atlas on glass plate. system since the original prototype The J atlas (a photographic blue filter) and the EJ equatorial became operational in 1985. The final extension were responsible for the discovery of numberless version, FLAIR-II, has now been quasars, unusual resolved objects, and a steady stream of decommissioned in order to make way for transients like comets, supernovae and asteroids. These its replacement, 6dF, expected to start atlases played a pivotal role in providing targets to be followed commissioning during the last quarter of up at the AAT. 2000. FLAIR-II has been scheduled for The R(SES) and ER red-light surveys have now been around 30% of UKST time over the past 8 completed, with the last few fields taken on film due to the years and has been highly productive. See unavailability of satisfactory plate material. The final glass- page 4 for an example of the scientific plate survey being projects carried out on FLAIR. undertaken at the 6dF will offer more science fibres (150) and UKST is an I-band improved sensitivity from its new detector. allñhemisphere The most significant gain, though, will be survey. Only 56 of the in much faster field turnñaround, as the 894 plates remain to robot slashes fibre configuration times from be taken. With 53 around four hours to less than an hour. The plates taken this two interchangeable field plates will allow year, we expect to 2dFñlike operation as spectroscopy complete this survey becomes the main observing mode of the in a little over a year. Schmidt.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 19 AUGUST 2000 astronomers and with the encouragement of the AAOís THE END OF AN ERA then Director, Don Morton, we initiated a service David Malin observing program. This ran for 15 years and allowed me and a succession of astronomers to hone their photographic skills by taking plates for others. In later The last photographic plate was taken on the AAT years I ran the program with Steve Lee, an AAT night SITE over a year ago. assistant and long-time friend and colleague.

I remember the strange feeling at the time I exposed it, A decade ago we had some kind of photography on the NEWS finally closing the shutter with more than a touch of AAT for 10 nights a year, and familiarity ensured that sadness. All the familiar sounds and sights of observing we had the shutter open for more than 90% of the night took on a haunted, echoing quality that night, which I available to us, something CCDs cannot match. On the somehow knew was the last for photography, though other hand CCDs detect ten times more photons than no-one had suggested it might be. The huge dome our best plates ever could. But there is still a profound seemed larger than ever, and the elusive screech in the satisfaction in completing a well-constructed observing windscreen that Gordon Schafer could somehow never program without losing a minute during a long night, manage to lubricate took on a louder, more piercing and using a technology that has revolutionised both tone. But the stars were still in their places as I looked astronomy and our knowledge of the universe in the again at the familiar Milky Way framed by the aperture last 100 years. We liked to think that each plate produced that Prince Charles had so famously declared open. at least one published paper.

I had sat there beneath the feeble light of the glorious Still in darkness, the plate now in the pungent stop bath, southern sky for many, many hours, sometimes cold, I recalled my conversations with Joe Wampler, the AATís tired or hungry or all of these, but always amazed that first Director, as we drove to Coonabarabran in for a night or two I was responsible for getting the best September, 1975. The telescope had just been from this beautiful telescope. The exposure ended and commissioned and this was my first trip to see it. Joe the telescope slewed to near horizontal at prime focus was keen to have some colour photographs to announce access. I clambered out of the telescope, struggled out of gloves and hat and made my way to the darkroom.

It was during the lonely dark of processing that the most poignant moments came. The tray rocker swished developer from side to side, to the rhythm I had set for it almost 25 years ago, a mantra passed to me by Bill Miller, doyen of our unusual trade. I joined the AAO knowing nothing about astronomical photography, but a week in Pasadena with Bill in 1976 set me on the right track.

Twenty minutes can be an eternity at six in the morning, especially in the dark, but I had deliberately designed the processing routine to be undemanding, to minimise mistakes when the need for sleep is overwhelming. And as the mind was freed, it wandered in the darkness to fleeting memories of unseen friends. I recalled Louise Turtle, who showed me how to use my first telescope, the AAT. I knew her as Louise Webster, and she was a natural teacher and a delight to know, still much missed. Louise was among the first of the AAOís research

ANGLO-AUSTRALIAN OBSERVATORY page 20 NEWSLETTER AUGUST 2000 the arrival of a new, wide field 4m telescope in the southern hemisphere. We talked about colour film and the Technicolor process, and my favourite, James Clerk Maxwellís three-colour system. But there was no time to SITENEWS experiment with exotic processes, so I took the first experimental colour pictures on 120 roll film in April, 1976. The log seems to show we did it in telescope time allocated to Mike Penston, Alan Wright and Bob Fosbury. You get it where you can. The results were promising enough to try sheet film, and the first useful, wide- field colour exposures were made in December that year. With the developed plates now safely in the fixer, the urgent bursts of nitrogen began the final stage of processing, and another wait was in prospect. My mind turned to my colleagues and friends at the UK Schmidt telescope who were so helpful as I struggled to set up a workable photographic system. The Schmidt was an exclusively photographic telescope that was in operation before the AAT. Sue and Keith Tritton, Liz Sim, Russell Cannon and many others had already tackled many of the hypersensitisation and processing problems that faced me and were generous with their The plates can dry for a while, but now itís time for bed, time and experience when I most needed it. I am and for dreams of what I might have accomplished if the eternally grateful for their friendship and support. It was AAT had been built 10 years earlier. from Schmidt plates that the first tri-colour images were Postscript made in 1978, for a book with Paul Murdin and David Allen, modestly called ìCatalogue of the Universeî. But The AAOís reputation for innovative and exciting thatís another story. astronomical photographs will continue far beyond the age of photography. As in other major observatories, At last the lights are on and I see what our last CCDs have long since displaced photography for exposures have captured. One of the still-dripping plates quantitative image recording, and CCDs are quite capable shows a group of galaxies, the Hydra-1 cluster (Abell of making fine pictures (see http://www.aao.gov.au/ 1060), now made into AAT colour picture number 116 images/general/aatccd.html). By the time this issue of (see http://www.aao.gov.au/images/captions/aat116.html). the Newsletter hits the streets the AAOís new Wide Another promises wonderful detail in an object that has Field Imager, constructed in collaboration with our been on my to-do list for many years. This is the red- colleagues at the ANU, will have been commissioned. light exposure, the first of what was intended to be a It offers a prime focus field half a degree in diameter trio of plates for a colour picture of the slightly exotic imaged on a mosaic of four 2000 x 4000 CCD chips. No ëCats-pawí nebula, NGC 6357. The remaining plates will more sitting at the end of the telescope beneath the never now be taken, but I reproduce on the left part of stars or sniffing the fumes of fixer in the dark. Like so the plate, which shows how the nebula got its name, much else today (including writing this piece) observing and above, an unusual billowing structure in a smaller time with WFI is spent in front of a computer screen, part of the nebula. This was revealed by one of the oblivious to the beauty of the night. Itís probably much techniques from a previous life that I pressed into use in more efficient, and certainly much more social than being astronomy. The thought of unsharp masking releases alone under the stars, but hardly likely to leave so many another flood of memories from a career as a lasting memories. microscopist long before bigger things caught my eye.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 21 AUGUST 2000 killing a human with one blow of their mighty feet, so beware, when trotting around in the springtime bushland, if you hear a booming sound ó run! But in the right direction, please! They stand at about 5 foot in height and can make a sizeable dent in a vehicle. They are LOCAL NEWS also the only creature I know that can run straight through a mesh fence without being diced in the process, probably† because they donít have the brains to realise they are dead. But the young ones are delightful in their striped pyjama suits and against the odds, make great pets. Emu numbers have increased in the hills over recent years (hence the driving hazard) because this is LETTER FROM COONABARABRAN their last retreat from farmers who take a dim view of Rhonda Martin flocks of emus rolling around in their wheat fields and pop off at them with all sorts of weapons. Emus are Kangaroos are a perennial problem on the roads between notoriously hard to kill, being mostly feathers and feet. Siding Spring and town. They come in all shapes and And then, of course, there are the koalas who take a sizes (usually degrees of huge) and show a particular rest in the middle of the road and watch with great fondness for Night Assistants, Frank Freeman in interest the approaching work bus labouring up the grade, particular. Frank lives in constant dread of these or the echidna (a very likeable, but prickly individual denizens of the night lying in wait for him on his lonely who is well aware of his status as one of the oldest drive home after night shift. Not that they wish to damage mammals in the world) who decides that digging up the him, or the car either, if it comes to that ó they just bitumen is the shortest way to the other side of the want to frighten the wits out of him. road. Australian fauna is interesting and around Siding Now Frank always drives sensibly and at a reasonable Spring, plentiful, but when one thinks about it at all, speed ó another reason they pick on him ó they can they are just a tiny bit dim. According to Ed Penny, actually see him, unlike Steve Lee who maintains that if they also have a definite anti-Pom bias which doesnít you drive fast enough atoms and molecules just pass do his Rover a deal of good. by each other without any actual contact. So every now So you see, observers, just what the staff at the AAO and again I find a vehicle accident report on my desk have to negotiate to ensure that the telescopes are at from Frank who advises plaintively that several big their best for your observing runs. But, being totally beasties held a ballroomñdancing competition on the dedicated they endure grimly being kicked by kangaroos bonnet of the car, or tried to rip off the bumpers with (always large) and emus (even larger) and pulling echidna their nasty big feet etc etc. There is rarely any serious prickles out of their tyres, just to make sure you are damage ó just annoyance value sent to stress out happy. Frank. The roos are mostly quite lovable creatures but they do tend to boast to each other about how they freaked out a Night Assistant, and the young bucks then want to try their luck. And Frank? He just wants to go fishing!

Another driving hazard, apart from tourists, is a large bird, the Emu. Now, an emu has the intelligence level of an iceberg although the female (she-mu) over the millennia has managed to con the male (he-mu) into raising their youngsters all on his own. Incidentally, while doing this they can become very dangerous indeed and are quite capable of

"Hey fellas, it's the night assistant! Heads down and nobody jump 'till you see the whites of his eyes!" Cartoon by Jonathan Pogson, AAT

ANGLO-AUSTRALIAN OBSERVATORY page 22 NEWSLETTER AUGUST 2000 EVENTS AT EPPING Ode from a Board Secretary Helen Woods Fishingís not so goodówhoís to blame? I love my whitingówhat a shame The UK summer students arrived at the AAO in July to take Itís not my fault says the professional man Itís all weíve done since time began NEWS LOCAL up their threeñmonth programs. Samantha Rix (Cambridge Itís not my fault the angler says University) is studying the 2dF galaxy redshift survey with Itís to the bag limit I always stays Joss Hawthorn. Emily MacDonald (University of Edinburgh) Whatís the point I am thinking is working with Stuart Ryder on the reduction and analysis While we argue the fish are sinking Then one day I see an ad ó of data taken with UNSWIRF and IRIS. Ceri Ashton (Cardiff A job at the AAOís to be had University) is working with Geraint Lewis and is looking at Whatís AAO my friends all say using microlensing to probe the nature of distant planets. I havenít a clue but it sounds OK

The AAO at Epping has said goodbye to a number of valued Well AAO is just to begin staff members over the last few months. Roger Bell, the Thereís AAT, and DETYA, my headís in a spin Well they seemed to like me and I got the job AAT Board Secretary and Public Relations Officer found a But acronyms to the surface did bob challenging position with the Lands Department of the NSW Thereís 2dF and IRIS2 State Government. At his farewell lunch he read us a light- And ATAC and PATT to name a few! hearted poem he composed about his time with the AAO What about Australis, Gemini and SOAR My friends were saying what a bore! and the affection he held for it. (following column). Carolyn But not for me, it was very exciting Hampele our personnel officer who replaced Greta Simms The world of astronomy was inviting during Gretaís maternity leave, has left the AAO and gone Such dedication and freshness, I was blown to China. She did a great job in Gretaís absence and, on Out into the expansive unknown Gretaís return stayed on a little longer to help Don and Devika I settled in and the time soon passed in the Accounts area get ready for the GST. Belinda OíBrien, Youíve been here three years I was asked who has been on maternity leave for a year now decided not A great bunch here but itís time to leave to return to the AAO. During this time Jeroo Mody looked Saying goodbye, itís hard to believe after us all with a helpful and enthusiastic attitude that we Thanks to Brian for true inspiration will not easily forget. Jeroo has now left for a position at the Thanks to others for their perspiration Department of Education, and we have pleasure in welcoming Thanks to you all for teaching me Marilyn Campbell to the AAO. Congratulations to Elizabeth About quasars, galaxies and cosmology Corbett and Gabriella Frost (nÈe Bogatu) on their respective Well off I go to what who knows nuptials. Congratulations also to Lew and Akhila Waller on But thereís sure to be arguing over river flows the birth of Malathi. Our sympathies are with John Straede Farmers, Greenies who is right? on the loss of his wife, Cheryl. I hope I donít lose sleep at night Well there it is, life circles round We would also like to welcome Will Saunders who arrived Whatís to say? What have I found? at Epping to begin work as one of the AAOís Research A great group of people ó not too profound Astronomers. Will previously worked as a Royal Society A vision not of this earth; How does that sound? University Research Fellow at ROE. His major interests are No, a special passion a special place A passion of the unknowable ó SPACE in mapping the local universe and he will be spending much of his time at the AAO working with 6dF.

As we go to press we bid farewell to Keith Taylor, who in his In his own words: "I have been associated with the 23 years (on and off) at the AAO has been pivotal in AAO now for well over two decades and have had a establishing the innovative and flexible suite of simply wonderful time. It's the most productive, instrumentation for which this observatory is well known. creative and happy establishment imaginable and Keith is personally responsible for Taurus, LDSS and, of it will be an enormous wrench to leave. I am proud course, 2dF. His involvement with instrumentation spans from to say, however, that I am leaving it in strapping the earliest instruments for the AAT, to his leading role in good health which is only a surprise to those who establishing the External Projects unit at the AAO. Keith are not familiar with its extremely positive culture leaves us to work on the CELT (California Extremely Large and outlook." Thanks, Keith, and keep in touch! Telescope) at the California Institute of Technology in And congratulations to Roger Haynes who has been Pasadena. We wish him and his family all the very best in appointed Acting Head of Instrumentation. this new venture.

ANGLO-AUSTRALIAN OBSERVATORY NEWSLETTER page 23 AUGUST 2000 .au .au > @aaoepp.aao.gov @aaocbn.aao.gov.au > @aaocbn.aao.gov.au < user < user RICKETTS Australia Fax +61 2 9372 4880 email 1710 1710 .au .au > editorial assistant SANDRA 4800 4800 .aao.gov.au/local/cgt/wfi/ .aao.gov HAKIS HAKIS ANGLO-AUSTRALIAN OBSERVATORY FIRST COMMISSIONING RUN FOR WFI ON THE AAT For further information see: information further For http://www wfi_pfu.html out to provide feedback for further development. Following runs on the 40", WFI will be on December back in action AAT on the 23. Despite these setbacks, the run was of pieces various The success. a overall demonstrated WFI together, fit jigsaw the 1 arcsec images despite a frosted carried were tests of plenty and detector, The photo on the right shows WFI being WFI shows right the on photo The lowered into the top end. An accidental resulted installation during vacuum of loss in frosting of WFI for the first night, and the of nights remaining the unfortunately commissioning run were clouded out. prime focus unit (PFU) has been built to Newsletter AAO (see WFI accommodate 2000). February 92, AAT, at the light first saw WFI August In Spring. Siding at arriving after days 3 only The The Wide Field Imager (WFI) is a joint project being carried out by the AAO, provide to Melbourne Uni. the and RSAA the at use for mosaic imaging 8k x 8k an anew and the AAT SSOAtAAT, the1m. StopPress AAT/Schmidt Telephone +61 2 6842 6291 Fax +61 2 6884 2298 email < http://wwwURL editor RAY STAT RAY editor ISSN 0728-5833 Published by PO Box 296 Epping, NSW Epping Lab Telephone +61 2 9372

THE BACK PAGE