New Zealand astronomy: the past, the present and the future
A review by John Hearnshaw, Professor of Astronomy at the University of Canterbury
January 2004
Index
1. New Zealand’s astronomical heritage
2. Cook’s voyages and the transit of Venus
3. Maori astronomy
4. The Transits of 1874, 1882
5. Notable early amateur astronomers
6. The first professional astronomers
7. N.Z. amateur astronomers in the 20th century
8. Some significant early telescopes in New Zealand
9. The Royal Astronomical Society of N.Z. and other regional societies
10. Carter and Auckland observatories
11. Astronomy in New Zealand universities
12. Mt John University Observatory
13. The 1-m McLellan telescope
14. The Hercules spectrograph
15. The MOA project
16. SALT
17. The future of New Zealand astronomy
1. New Zealand’s astronomical heritage
Few nations can claim that astronomy played a pivotal role in their founding and history. But New Zealand can be proud that astronomy was one of the principal motivations which led to the exploration of this land, and its eventual settlement by Europeans. For when Captain James Cook first came to New Zealand in 1769, it was the observation of a transit of Venus that was one of the reasons for his being sent by the Royal Society to the south Pacific.
Very probably, though less well chronicled, astronomy also played an important role for the Polynesian settlement of New Zealand some hundreds of years before Cook. For astro-navigation may have been an important aspect of allowing the Maori to make long sea voyages across the Pacific that ended in their settlement of Aotearoa.
2. Cook’s voyages and the transit of Venus
In 1769 the Royal Society organized an expedition to the South Seas for the purpose of making observations of the transit of Venus across the Sun, a rare event which had occurred in 1761 and was to occur again in 1769. Observations of the timing of this event at different locations on Earth were known in principle to give the absolute dimensions of the solar system, including the value of the astronomical unit (mean distance of the Earth from the Sun) in miles or kilometres. Cook and his astronomical assistant Charles Green on the Endeavour duly observed the transit from Tahiti on June 3, 1769. Analysis of the data was not however very successful in the aim of calibrating the astronomical unit.
Cook then sailed on to New Zealand, and here the major task of mapping the New Zealand coastline ensued. With Green he made important observations from Mercury Bay in the Coromandel, where they observed a transit of Mercury. Charles Green, can be regarded as the first professional astronomer to work in New Zealand. Sadly he became ill on the return voyage to Cape Town and died in January 1771 before his arrival back in England.
Later, on the second (1773-74) and third (1777) expeditions, extensive astronomical observations for determining latitude and longitude using precise Kendall chronometers were made by Cook and his astronomers from Dusky Sound and from Ship Cove in Queen Charlotte Sound. William Wales (2nd voyage), William Bayly (2nd and 3rd voyages) and James King (3rd voyage) were the accompanying astronomers.
More information on this early nautical astronomical history of New Zealand can be found in Wayne Orchiston’s excellent monograph: Nautical Astronomy in New Zealand, published by the Carter Observatory Board (1998). There is an article on Cook’s voyages that discusses the transit of Venus observations in some detail by George Eiby in Southern Stars, 23, 140-152 (1970).
3. Maori astronomy
The Maori from early times have developed some astronomical knowledge which is closely entwined with Maori mythology. Certainly the Maori recognized several constellations or stellar patterns in the sky, the brighter planets as well as the Sun and the Moon. The Pleiades, Matariki, plays a key role in determining the beginning of the Maori new year when this star cluster is seen to rise just before dawn. The extent to which the Maori used the stars for navigation on their long voyages is uncertain, but may have been of some importance. What is certain is that the Maori have developed a rich mythology based on Rangi (sky father), Papa (the Earth mother) and their progeny of Te Ra (the Sun), Te Marama (the Moon) and Nga Whetu (the stars), and that they understood the relationship of celestial phenomena to the seasons on the land and the growing of crops.
The standard early reference on Maori astronomy is Elsdon Best’s The astronomical knowledge of the Maori (first published 1922; new edition 1955 published as Dominion Museum Monograph no. 3). Also one can refer to a paper by C. Kingsley-Smith in Southern Stars, 22, 5-10 (1967) on Maori star lore, The illustrated encyclopedia of Maori Myth and Legend by Margaret Orbell (Canterbury University Press, 1995) and Wayne Orchiston’s Nautical Astronomy in New Zealand (1998), which is cited above.
4. The Transits of 1874, 1882
The link between New Zealand and transits of Venus became once again an important part of our astronomical history for the next pair of transits after Cook. These were in December 1874 and December 1882, and in both cases observable from New Zealand. An American expedition to Queenstown in 1874 is well documented, and was one of seven expeditions sent into the Pacific from the U.S. Naval Observatory in Washington. A total of 237 photographs were obtained of the transit from Queenstown. Another expedition from USNO went to the Chatham Islands. Once again, the calibration of the scale of the solar system was the prime motivation. A paper by Steve Dick, Tom Love and Wayne Orchiston discusses the Queenstown expedition (Dick, Love and Orchiston: Queenstown and the 1874 Transit of Venus, Carter Observatory Information sheet no 11 (1998)) and there is also a paper by Orchiston, Love and Dick in the Journal of Astronomical History and Heritage 3, 23 (2000). A British expedition to Burnham near Christchurch had cloud for the transit.
Further expeditions were mounted for the 1882 transit, the British again going to Burnham and the Americans to Auckland. Several amateur astronomers in New Zealand also observed this event. Wayne Orchiston’s Nautical Astronomy in New Zealand (1998, cited above) gives details. Also refer to a paper on early New Zealand astronomy by R.A.McIntosh in Southern Stars, 23, 101 (1970).
5. Notable early amateur astronomers
New Zealand has an illustrious history of distinguished amateurs who have made excellent observations at their home observatories. John Grigg (1838-1920) was one such early amateur. He was born in Kent, migrated to New Zealand in 1863, established a music shop in Thames and built himself an observatory there in 1884 and became an avid comet-hunter. He was the discoverer or co-discoverer of three comets that bear his name, in 1902, 1903 and 1907, and he was one of the first to undertake astro-photography in New Zealand. More details are in Wayne Orchiston’s article (Southern Stars 40, (no.3) 14 (2001)).
Others followed, taking advantage of the clear unpolluted southern skies and the spirit of do-it-yourself innovation that prevailed in the early colony. Thus Henry Skey (1836-1914) in Otago (R.N.Campbell, Southern Stars 40, (no. 2) 11 (2001)), Thomas King (1858-1916) in Wellington (J.B. Seymour, Southern Stars 36, 102 (1995)), Arthur Atkinson (1833-1902) in Nelson, James Townsend (1815-1894) in Christchurch and Arthur Beverley (1822-1907) in Dunedin were all notable amateurs who equipped their private observatories with small telescopes, and many of these were inspired by the 1882 transit of Venus to take up and further pursue astronomy. Wayne Orchiston’s book Nautical Astronomy in New Zealand provides excellent reference material.
New Zealand even had an accomplished optician and telescope maker in Joseph Ward (1862-1927), who helped to establish the Ward Observatory in Wanganui, and whose telescopes included a 52-cm Newtonian reflector (built 1924), which for many years was the largest telescope in New Zealand. Two articles on Ward have appeared in Southern Stars: one is by D. Calder (vol. 27, 104 (1978)), the other by Wayne Orchiston (vol. 41 (no.2), 13 (2002)).
6. The first professional astronomers
In 1863 the first ‘official’ observatory was established by the Wellington provincial government. Archdeacon Arthur Stock (1823-1901) was put in charge and, equipped with clocks and a transit telescope, he was able to provide a time service and he operated a time ball from the custom house on Queen’s wharf. By 1868 this became the Colonial Time-service Observatory with Sir James Hector, the noted geologist as director and Stock as observer. He was New Zealand’s first professional astronomer.
For more on Stock, see Wayne Orchiston’s Nautical Astronomy in New Zealand and In spite of his time, a biography of R.C. Hayes by Margaret Hayes (published by the N.Z. Geophysical Society (1987)). Thomas King succeeded Stock, and Dr C.E. Adams succeeded King in 1911. Adams distinguished himself as a computer of cometary orbits as well as an observer. The Colonial Observatory was resited in Kelburn in 1907 and known then as the Hector Observatory. The Hector Observatory was renamed the Dominion Observatory in 1926.
Professional astronomers were not numerous in early New Zealand, but two other individuals of note deserve mention. Professor Alexander William Bickerton (1842-1929) was foundation professor of chemistry and physics at the Canterbury University College from 1874 until he was fired by the college council in 1902, ostensibly for poor management. Bickerton was a brilliant but unorthodox lecturer, whose star pupil was Ernest Rutherford. But he had a bizarre and largely untenable theory (the partial impact theory, as he called it) on stellar collisions as the origin of variable stars including novae and for the origin of the solar system. These theories led to his papers being shunned and discredited by the professional community in England. More on this colourful character is to be found in Gerry Gilmore’s article (Southern Stars 29, 87 (1982)). There is also a biography by R.M. Burdon, Scholar Errant (Pegasus Press, Christchurch, 1956).
A.C. (Charles) Gifford (1861-1948), who taught mathematics at Wellington College, was also a keen astronomer and he had access to one of the best equipped school observatories. His theories of the origin of the lunar craters by meteorite impact were published in 1924 and 1930, and were an early exposition of what is now recognized as the correct interpretation of the lunar landscape. The college acquired a 5-inch Zeiss refractor in 1924, and this was fully restored in 2002 after falling into disrepair.
When the Carter Observatory was founded in 1941, Murray Geddes (1909-44) was appointed the first director. However he never formally took up this position, being called away on war service and he did not return to New Zealand. Ivan Thomsen (1910-69) was his successor from 1946 to 1969. He had previously worked under C.E. Adams at the Dominion Observatory.
7. N.Z. amateur astronomers in the 20th century
The fine tradition of amateur astronomy in New Zealand continued throughout the 20th century and up until the present time. This review mentions just three of some distinction among the many who have pursued astronomy as a hobby.
One was Ronald McIntosh (1904-1977), who became a distinguished meteor observer. In 1935 he published his Index to southern meteor showers. He also monitored meteor rates and analysed the methods of obtaining meteor orbits from the observed path. McIntosh published in the Monthly Notices of the Royal Astronomical Society in London, he directed the meteor section of the Royal Astronomical Society of New Zealand, and for a time he also directed the Auckland Planetarium.
Frank Bateson (b. 1909) in Tauranga is another distinguished astronomer who founded the variable star section of R.A.S.N.Z. in 1927 and has directed it from that time to the present day. Not only was he a prodigious observer of variable stars, but his VSS of R.A.S.N.Z. collated observations from dozens of other observers in New Zealand and overseas. This great body of material has resulted in the publication of charts, circulars and publications containing visual observations of many stars. Dwarf novae, novae and Mira stars were all studied in much detail, and the fact that many variables had data collected in a continuous record going back six or seven decades has provided an invaluable data resource for many professionals. Frank Bateson is as a result widely respected amongst professional astronomers world-wide, and he has been honoured in New Zealand with an OBE and honorary doctorate from Waikato University. Frank Bateson was also instrumental in establishing Mt John University Observatory in the early 1960s, when he conducted an extensive site-testing campaign on behalf of the University of Pennsylvania to determine the best location (see F.M. Bateson: Publ. Univ. Pennsylvania, Astron. Series, vol. X, pp iv + 139 (1964)). Mt John was chosen as a result, and Frank became the first astronomer-in-charge in 1965 until his retirement in 1970. A tribute to Frank Bateson can be found in an editorial by Ed Budding in Southern Stars 33, 169 (1989), followed by an article by Albert Jones in the same volume (pp. 170-171). Frank has described the VSS in Southern Stars 40, (no. 3), 7 (2001).
Finally Albert Jones (b. 1920), who lives in Nelson, is the world’s most prolific observer of variable stars. Since the early 1940s he has amassed over half a million visual observations, in some years as many as 13,000 annually, and his magnitude estimates are distinguished by exceptional reliability and precision. Albert Jones was a co-discoverer of the famous supernova 1987A in the Large Magellanic Cloud and he discovered a comet in 1946. He too was awarded an OBE and has received international recognition for his work, which continues to this day. A tribute to Albert Jones is to be found in Rod Austin’s article in Southern Stars 36, 36-42 (1994).
8. Some significant early telescopes in New Zealand
New Zealand has been fortunate to acquire some remarkable old telescopes by famous manufacturers in America and Great Britain. Most of them came here as a result of the amateur astronomers in New Zealand. A selection based on aperture and pedigree is mentioned here.
Thomas Cooke of York, England, was one of the most famous telescope makers and opticians in Britain in the 1860s. Several New Zealand telescopes are of Cooke manufacture. The largest and oldest of the telescopes in working order is the Ward Observatory Cooke refractor of 9.5 inches aperture in Wanganui. The telescopes optics were made between 1859 and 1860, and the instrument was purchased for the Wanganui City Observatory (later renamed the Ward Observatory) in 1903. Joseph Ward was the first observer with this telescope. The instrument is described in articles by C.T. Harper et al. (Southern Stars 33, 281 (1990)) and G.R. Nankivell (Southern Stars 36, 1 (1994)).
Another Cooke telescope of almost the same size (originally 9⅓ inches, later 9 inches from 1896) was built in York in 1866-67 for the well-known English amateur, Edward Crossley (see F.P. Andrews and E. Budding, Southern Stars 34, 358 (1992)). This telescope came to New Zealand in 1907 for the Meanee Observatory, near Napier, of the Rev. David Kennedy (1864-1936). In the mid-1920s the Wellington City Council purchased it from Kennedy’s estate and by 1942 the telescope was installed in the newly opened Carter Observatory in Kelburn. It received its third objective lens in 2001.
The largest refracting telescope in New Zealand came here in 1962. It is the 18-inch refractor by the American optician John Brashear, which was formerly erected at the Flower Observatory of the University of Pennsylvania. This telescope dates from 1897, though the Brashear optics are a few years older. It was to have been installed at Mt John, but funds for the building were never realized. Now there are plans to donate this famous old telescope to a museum.
Several other smaller telescopes of distinction also date from the late 19th century. New Plymouth Observatory acquired a 6-inch Alvan Clark refractor in 1920. It was formerly at the Sydney Observatory and dates from 1881. Clark was the foremost American optician in the late 19th century (W. Orchiston, Southern Stars, 34, 277 (1991)). Another 6-inch refractor is at the Townsend Observatory in Christchurch. It was made by Thomas Cooke in 1863 and was acquired by the Canterbury University College in 1891 and installed in 1896. It is still owned by the University of Canterbury and is in regular use for public viewing.
Another refractor of similar aperture was the 5½-inch Grubb refractor made in Dublin in 1882. It was owned by Thomas King, the observer at the Colonial Observatory in Wellington. After King’s death in 1916, it was acquired by the Wellington City Council and erected as the King Edward VII Memorial Observatory in 1918 in Kelburn. Later this became known as the Thomas King Observatory (see J.B. Seymour, Southern Stars, 36, 102 (1995) and G. Hudson, Southern Stars, 42 (no. 4), 4 (2003)).
One old reflector of note was made by George With and John Browning in England, probably about 1870, and was acquired by J.H. Pope, an Otago school teacher in about 1871. The subsequent chequered history of this telescope is given by Tony Dodson in Southern Stars 37, 45 (1996). Another With-Browning reflector, of aperture 9¼ inches, was owned by the amateur observer Henry Skey (1836-1914) in Dunedin. The telescope passed to Skey’s son in 1914 and eventually was donated to Ashburton High School in 1925. The telescope was refurbished and housed in a new building between 1974 and 1977. A detailed article was published by Bob Evans and Ken Lucas, who were involved with the refurbishment (R.W. Evans and K.J. Lucas, Southern Stars 33, 178 (1989)).
9. The Royal Astronomical Society of N.Z. and other regional societies
The New Zealand Astronomical Society was founded in 1920, and formed a nation-wide umbrella organization to which the many regional societies have become affiliated. In 1946 N.Z.A.S. acquired its royal charter, and accordingly became the Royal Astronomical Society of New Zealand. R.A.S.N.Z. is a rare example of an astronomical society that flourishes with both amateur and professional members, and indeed one of the strengths of the New Zealand astronomical scene has been the healthy interaction between these two communities. The society is run by a council and president and contains a number of sections for different interest groups. Of these the Variable Star Section, directed since 1927 by Frank Bateson, is certainly the most famous. Other sections cover aurorae, comets and minor planets, occultations and photometry; astronomical computing and meteors sections have also existed in the past. The society holds an annual general meeting and conference, publishes the journal Southern Stars and also a monthly newsletter.
More information on R.A.S.N.Z. can be found from the society’s website at www.rasnz.org.nz.
Astronomical societies are to be found in all the main centres in New Zealand, with over 600 members for the strong Auckland Astronomical Society. As many as 24 regional societies are currently active in New Zealand. Many of these societies now run their own observatories (for example the Joyce Memorial Observatory of the Canterbury Astronomical Society near Christchurch).
10. Carter and Auckland observatories
The Carter Observatory in Wellington came into being in 1941 as a result of a generous benefaction by the Wellington businessman, politician and Wairarapa farmer, Charles Rooking Carter on his death in 1896. The original bequest of £2000 was not sufficient to found an observatory, but after many delays, the Carter Observatory came into being in December 1941 in the Botanical Gardens in Kelburn. Murray Geddes, a Victoria University College graduate and Southland school teacher became the first director. However war service prevented him from taking up the position. He was a keen observer of meteors, sunspots, variable stars and aurorae.
The Carter Observatory houses the 9-inch Cooke refractor, and in 1968 it acquired the 41-cm Ruth Crisp reflector. In 1977 Carter Observatory was given the title “National Observatory of New Zealand”. A planetarium was built there in 1992 and the role of the observatory as a regional resource for astronomy education and public outreach has thereby been strengthened. The Carter website is at www.carterobs.ac.nz.
The Auckland Observatory on One Tree Hill opened in 1967 and houses a 50-cm Zeiss Cassegrain reflector funded from a donation by Edith Winstone Blackwell. It has been used for photometry of variable stars. The telescope was fully restored in 2003. The Observatory is part of the Auckland Stardome which features a Zeiss Planetarium, completed in 1997. The Stardome website is www.stardome.org.nz.
11. Astronomy in New Zealand universities
Although at the present time astronomy as a subject for teaching and research is very much concentrated at the University of Canterbury, several of New Zealand’s other universities have also had or do have an interest in teaching and researching into astronomy. At present Canterbury’s Department of Physics and Astronomy has five academic staff who specialize in optical astronomy, mainly with interests in stars. In addition one staff member has an interest in the solar system, in particular meteoroid dust particles in the solar system (observations of their orbits are made at the meteor radar facility at Birdlings Flat near Christchurch) and two staff members are interested in cosmology or astro-particle physics. One of these is a theoretician specializing in general relativity and gravitation, the other works on problems of neutrino astrophysics, and in particular the opportunity of detecting neutrinos from outer space by the interaction with the ice shelf in Antarctica (the so-called international IceCube project).
Canterbury also has academic staff with interests in different aspects of astronomy and space science in other departments. Thus the Department of Electronic and Computer engineering has an interest in astronomical imaging through a turbulent terrestrial atmosphere and the technique of adaptive optics (a method of producing sharper images by compensating for the blurring of the atmosphere with a very fast computer controlled mirror), the Department of Chemistry has an interest in interstellar chemistry and planetary atmospheres, and the Department of Geological Sciences has an interest in planetary geology and vulcanology. This wide range of expertise makes Canterbury the clear leader in astronomy amongst the New Zealand Universities.
Four other universities currently have significant programmes in teaching and research, though each has only one academic staff member. Thus Auckland University collaborates in the MOA project (see below), an international programme with Japanese scientists for which the observations are made at Mt John. Victoria University of Wellington also is part of this project. At the Auckland University of Technology, one staff member has an interest in theoretical aspects of radio astronomy and galactic structure. At Massey University’s Albany campus, one staff member in mathematics has an interest in stellar dynamics. Otago and Waikato universities have also employed astronomers in the past, but these astronomical programmes have now lapsed. Having said that, all New Zealand universities teach physics and most of the physics programmes offer some astronomy, mainly at an introductory level. Only at Canterbury can courses be done at any level from years one to three or at honours level (year 4). Canterbury also offers a master’s degree in astronomy. Canterbury, Auckland and Victoria universities have all had recent PhD students in astronomy. Indeed Canterbury typically has 8 to 10 graduate students (MSc or PhD) enrolled at any one time.
Information about the teaching and research in astronomy at Canterbury can be obtained from www.phys.canterbury.ac.nz.
12. Mt John University Observatory
Mt John University Observatory was founded in 1965, as a joint project between the universities of Pennsylvania and Canterbury. The observatory is located at Lake Tekapo, in the centre of New Zealand’s South Island, at a dark-sky site where there is a maximum chance of clear skies. Although the involvement of Pennsylvania was active for the first ten years at Mt John, this is no longer the case and since about 1975 the observatory has been effectively run by the University of Canterbury.
The first major instrument to be installed there were three astrographs used for sky photography, of apertures 100, 125 and 250 mm, and all mounted on a single equatorial mount under a sliding roof. The astrographs came from the University of Pennsylvania and they were used in the late 1960s to produce a photographic atlas of the southern sky, known as the Canterbury Sky Atlas. This was in fact a southern extension of a similar northern hemisphere photographic survey made from Lick Observatory in California.
In 1970 Pennsylvania provided a 60-cm aperture Cassegrain reflecting telescope for Mt John. This telescope is known as the Optical Craftsmen telescope, and it was equipped with a photoelectric photometer for measuring the brightness of stars. Mainly variable stars were the topic of interest, these being stars that vary in brightness as a result of pulsations, explosive eruptions or eclipses of a binary system. All these types of variable star have been the subject of intense study at Mt John over the last nearly four decades.
In 1975 Canterbury provided a second telescope made by the firm of Boller and Chivens in the United States. This telescope is also of 60-cm aperture, and it was the first to be used for stellar spectroscopy at Mt John, from 1976. It has also been used for photoelectric photometry and for direct photography of the sky. But since 1995 this telescope was completely refitted and given a new drive and optical system to make it suitable for the MOA project, which involves wide angle CCD imaging of crowded star fields to undertake measurements of stellar brightness. The MOA project is discussed further below.
The 1-metre McLellan telescope, currently New Zealand’s largest telescope, was designed and built at Canterbury and installed at Mt John in 1985. Although it can be used for photometry and imaging, the great majority of all time allocated on it is for high resolution spectroscopy of stars. For this purpose the Hercules spectrograph is used. The data can be used for measuring stellar velocities, their temperatures, pressures, chemical composition, rotation rates and other interesting parameters.
A fourth reflecting telescope for Mt John is currently under construction in Japan. It will have a 1.8-m aperture and a large CCD electronic camera will be mounted at the prime focus. This telescope will be used primarily for CCD photometry as part of the ongoing MOA project. The telescope is due for installation in the second half of 2004.
Further information about Mt John can be obtained from the web sites at www.phys.canterbury.ac.nz or www.mjuo.canterbury.ac.nz/mjuo.
13. The 1-m McLellan telescope
The design for the McLellan 1-m telescope was undertaken at Canterbury in the early 1980s, with the assistance of Norman Rumsey and Garry Nankivell working at the Physics and Engineering Laboratory (now Industrial Research Ltd) of the former DSIR in Lower Hutt. The optical design of this Cassegrain telescope is a so-called Dall-Kirkham arrangement, with an ellipsoidal figure for the primary and spherical secondary. That system has rarely been used in the past because of the significant aberrations as one observes stars off the central axis, which degrade the images. But Rumsey showed that with a suitable system of lenses just before the final focus, sharp images could be achieved even for a one-degree field of view. What is more, he argued that the Dall-Kirkham was much easier to make than the more traditional Ritchey-Chretien arrangement. The optical figuring of the mirrors was undertaken by Garry Nankivell, who was seconded to Canterbury for six months in 1981. Low expansion Zerodur ceramic was used for the mirrors.
The mechanical design and construction was by technical staff at the University of Canterbury. It is a traditional asymmetric single-pier equatorial mounting. The electronics and control system were also a local Canterbury product, including the drive system, encoding and computer control.
The whole telescope was completed in late 1985 and installed at Mt John in early 1986. It was installed in a building on Mt John formerly used by the US Air Force for tracking satellites, but which had become vacant in the early 1980s and was completely refitted and modified to accommodate the new telescope. Canterbury built an 8-m dome for the new installation. The telescope was opened in July 1986 and named after Professor Alistair McLellan, the former head of the Physics Department at Canterbury. It has been in almost uninterrupted operation on clear nights ever since 1986, with stellar spectroscopy being the main area of research for which it has been used. The photometry of stars with a CCD camera and the tracking of asteroids are other noteworthy projects undertaken with this telescope.
14. The Hercules spectrograph
In 1975-77 Canterbury built a high dispersion echelle spectrograph for Mt John based on a design provided by the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. This was at the time a novel kind of instrument using a special type of diffraction grating called an echelle to disperse the light into its component colours. The new echelle spectrograph, which was one of the first of its type in the southern hemisphere, was mounted on the Boller and Chivens 60-cm telescope in 1977 and used for recording the spectra of bright stars. At first these were recorded photographically, but later with electronic image intensifier tubes, then with an electronic diode array digital detector and finally with a charge-couple device (CCD).
This instrument was retired in 2001.
In 1998 work had begun on a much larger and more powerful spectrograph, the High Efficiency and Resolution Canterbury University Large Echelle Spectrograph (HERCULES) which was designed and built at Canterbury. This is an instrument linked to the telescope by an optical fibre and the whole spectrograph is mounted inside a vacuum tank in a specially insulated room to maintain exceptional stability.
The HERCULES spectrograph was installed in 2001 and had its first light in April of that year. Today it is the main instrument used on the McLellan telescope. It is used to analyse the spectra of variable stars and, for example, to measure precise velocities of stars using the Doppler effect. Since 2003 two planets orbiting stars other than the Sun were found using this spectrograph.
More information on the Hercules spectrograph can be found at www.phys.canterbury.ac.nz/~physsib/.
15. The MOA project
If by chance a massive object (a star or perhaps a black hole) passes precisely between us and a distant star, then a phenomenon known as gravitational microlensing can take place. This is caused by the bending of light rays by the gravitational field of the intermediate massive object (the lens), with the result that the light from the distant star can be amplified in brightness, typically for a few weeks or a month while the alignment of the source star, lens and Earth is nearly perfect. Although this was predicted many decades ago by Einstein, the first microlensing event was only discovered in the early 1990s. The main reason is that the alignments are so rare, that millions of stars have to be searched to find one undergoing microlensing.
In 1995 a project began at Mt John, mainly supported by Auckland, Canterbury and Victoria universities in New Zealand and Nagoya University in Japan. About 30 scientists from these four universities and several other institutions are involved in the project. It is known as the MOA project, meaning Microlensing Observations in Astrophysics. All the observations for MOA have so far been made with the 60-cm Boller and Chivens telescope at Mt John, using observers from both New Zealand and Japan. The objects viewed are the Magellanic Clouds (two small satellite galaxies of our Milky Way Galaxy) and the Galactic Bulge near the centre of our Galaxy. In these regions of the sky (which are only easily visible from the southern hemisphere) millions of stars can be observed in one exposure, giving a reasonable chance of finding microlensing events should they occur. Fifty or so events are discovered annually by the MOA team.
The principal aims of MOA are to discover and make observations of microlensing events in order to learn more about dark matter such as black holes in the Galaxy and possibly to discover planets in orbit around other stars (if the lens is a star, which normally will not be bright enough to be visible, happens to have a planet in orbit around it, then this may influence the way the source star’s light is amplified in a characteristic way that can allow new planets to be discovered). In fact MOA has discovered one planet using this technique in 2003, and possibly another in 1998. The 2003 event is the only probable planet discovery by microlensing.
In 2003 the Japanese principal scientist in the MOA project obtained a grant of about $7 million for a new larger telescope for the MOA project. This new 1.8-m telescope is now under construction in Japan and will be installed at Mt John in the second half of 2004. It will have a Russian made Astrosital mirror and the mounting is an alt-az mount, in which the two axes are always vertical and horizontal. A very large CCD camera with 80 million pixels and covering a field of view of about 1.5 degrees will be mounted at the prime focus.
The optics for the new MOA telescope were designed in New Zealand at Industrial Research Limited, who will also make the four corrector lenses used for producing sharp images, and which are mounted just in front of the CCD detector.
More information on the MOA project can be found at www.phys.auckland.ac.nz/moa/index.html.
16. SALT
SALT is the Southern African Large Telescope. This is a large 10-m class telescope of novel design currently under construction at the South African Astronomical Observatory at Sutherland some 400 km NE of Cape Town. The telescope is now nearing completion. In May 2000 the University of Canterbury became a partner in the SALT consortium, being one of about a dozen partner countries or institutions in South Africa, the United States, Poland, Germany and Britain. Canterbury bought a roughly 5% share in SALT in return for funding for the telescope and for the design and construction of one of three major instruments. In Canterbury’s case, the instrument bid for was for the high resolution echelle spectrograph, similar to but larger than HERCULES now in operation at Mt John. At the time of writing the start of construction of the new instrument for SALT is expected later in 2004.
SALT will also have a lower resolution spectrograph (for observing fainter objects) known as PFIS (prime focus imaging camera) being built by the University of Wisconsin, which is one of the SALT partners, and a direct imaging CCD camera known as SALTICAM, being built at SAAO in Cape Town.
Once SALT is operational Canterbury astronomers will have the opportunity to obtain data on one of the world’s largest telescopes and to do research into fainter and more distant objects beyond our local region of the universe.
For more information on the SALT project, see www.salt.ac.za. For information on the Canterbury spectrograph being designed for SALT, go to www.phys.canterbury.ac.nz/~physsib.
17. The future of New Zealand astronomy
Astronomy world-wide has undergone a fundamental revolution over the last hundred years. That should be evident, even to a casual reader of this account of astronomy in New Zealand. In most of the 19th century and before, astronomy was first of all, an aid to maritime navigation and a means of accurate mapping of localities on the Earth. To this end, time-keeping and astrometry, the science of measuring star positions with high precision, were two of the principal tasks undertaken by astronomers.
Starting in the 1860s, changes in the way astronomers in Europe practised their science began to take place. For the first time they began to ask fundamental questions about the physical nature and properties of the stars. At first physics was hardly advanced enough to provide many answers. But physics also underwent a revolution, and by the early twentieth century astronomers began applying physics to interpret their observations. This revolution was only really successful from the 1920s, when a real understanding of stellar spectra using physics became possible. Thus was born the branch of astronomy called astrophysics.
The development of New Zealand astronomy mirrors these developments on a world scene. Certainly the first New Zealand astronomers practised time-keeping, navigation, the determination of geographical coordinates and astrometry. Later observers studied meteors and comets and theoreticians speculated on the nature of variable stars (Bickerton) and the origin of lunar craters (Gifford). It is fair to say that New Zealand was slow, however, to embrace astrophysics. The Carter Observatory, established in 1939, undertook some solar physics, and a photoelectric photometer to measure star brightness was used there soon after the second world war. But lack of resources prevented a fully-fledged research programme to be developed. Further study of meteors by radar was made at Canterbury in the 1950s and 60s. But only when Mt John Observatory was established with American help in the 1960s can we say that a firm base in observational astrophysics was established in New Zealand. By this time observatories specializing in astrophysics had already celebrated over 50 years or more of existence in many European countries and in North America, and the Commonwealth Solar Observatory in Canberra Australia was founded in 1922. In this sense, New Zealand has had a late start in astrophysical research.
With Mt John now a high-tech and successful research observatory, with astronomy and astrophysics being taught and researched in at least four if not five New Zealand universities, and with important contributions to astronomy from a thriving amateur community, and New Zealand’s participation in international astronomy projects such as MOA, IceCube and SALT, the future of astronomy in New Zealand now looks very bright. In spite of a late start, there is no doubt that we are now making a significant mark on the world scene in selected areas of astronomy and astrophysics. Perhaps only about a dozen professional astronomers actually work in New Zealand (the number depends on how one defines an astronomer), mainly in our universities. On the other hand about four dozen New Zealanders are professional astronomers overseas, and many have been or are astronomers of international distinction. If we add these people to the tally of astronomers in New Zealand, including a dozen or more amateur astronomers who make valuable research contributions, there is no doubt that in proportion to our total population, New Zealanders are making a huge contribution to the world of discovery in astrophysics and space science. And it’s a contribution of which New Zealanders as a nation with an astronomical birth can justifiably be proud.
Acknowledgement: The author of this review thanks Alan Gilmore and Pam Kilmartin for helpful discussions and for drawing my attention to many of the references cited in the text.
