Black Birch resurrected
Unusual bumps in the night have had more than one farmer peering over the fence in rural Wairarapa recently. But perhaps such disturbances are only to be expected as an 11-hectare site near the town of Carterton undergoes preparation to become the largest astronomical research facility in the North Island, one which will house the largest fully automated telescope in the country.
A group of professional and amateur astronomers has banded together to build a series of observatories on the dark sky site (so named because of its remoteness from sources of light pollution), the largest of which will have a sevenmeter- diameter dome. This particular observatory is hardly new-it has already had a mysterious and controversial past as the United States Naval Office Black Birch Observatory near Blenheim.
In the 1970s, Black Birch, together with Woodbourne, Mount]ohn and Harewood, was identified as part of the American military presence in New Zealand. The observatory made detailed sky photographs and also collected very precise positional information on stars. Speculation was rife that the survey provided data for targeting tactical nuclear weapons-in short, that the observatory’s purpose was to set up a guidance system for Tomahawk missiles, thus tying New Zealand to the nuclear arms race.
In 1996, when the Americans decided their survey work was complete and made moves to pull out of New Zealand, Carter Observatory astronomer Richard Hall and Kotipu Place Observatory astronomer Gordon Hudson contacted the US Naval Office to inquire what it planned to do with the equipment associated with over two decades of survey work.
They were told that all assets associated with Black Birch had already been passed over to Operation Deepfreeze in Christchurch. Hudson says the story from there is surprisingly simple.
“We found out who was in charge of it all, made some phone calls and then sent him an application. They turned around and said, ‘Yes you can have it; you can take the whole building and anything left in it.”‘ This didn’t include the actual telescope, but took in everything else—from door handles to dome, and even a pair of ultra-accurate caesium atomic clocks.
The dismantling was done in March 1997 by Hudson, Hall and several colleagues. Says Hall: “We videoed ourselves dismantling the observatory so we can play it backwards to figure out how to put it together again.”
For a year the dismantled dome and other equipment remained in storage, as it became apparent to the astronomers that both logistically and financially the reconstruction job was beyond them. It was then that they formed the “Phoenix Society for the Resurrection of Black Birch,” which has since attracted 115 members, bringing together experts in robotics, electronics, and optics as well as blocklayers, electricians, plumbers and every other type of skill needed to get the operation off the ground. All “the bits” are now parked under Hudson’s house as Phoenix Society members prepare the site at Ahiaruhe.
Hall says the Black Birch dome, renamed the Ahiaruhe Dark Sky Observatory, will be a first-class research observatory, capable of doing work of an international standard, and is the first of its kind to be built by a private group in New Zealand.
“At the moment, all big observatories with this sort of equipment are either run by universities or other government bodies, and many members of the public interested in astronomy lack any opportunity to use large telescopes. We also have a lot of young people and professionals in the Wellington area who are interested in doing research work, but currently they have to travel to Canterbury University to get access to facilities. This observatory will enable us to carry out research only an hour’s drive from Wellington.”
The first observatory being built on the site is a “run-off roof” observatory, where the whole roof rolls away, leaving only the walls. “This is primarily for teaching people astronomy,” says Hall. “It’s much easier if people can see a larger area of the night sky than the slice glimpsed through a dome roof. We have three telescopes to install in here, the largest a 23-inch reflecting telescope, and we also have the Peter Reid six-inch refractor telescope, which the Carter Observatory is leasing to us—an excellent telescope for observing planets—and a 10-inch Schmidt-Cassegrain telescope for photography.”
Peter Reid used to present an astronomy programme on television in the 1970s called The Night Sky. When he died 10 years ago his telescope was donated to the Carter Observatory.
The next project will be to build the large research telescope itself, which will be fully automated so that it can be programmed to observe any object or series of events that astronomers wish to photograph. Should cloud obscure the sky, the telescope will close itself down. Hall says that as well as photographing, the computer will record a variety of data that is not observable with the naked eye—such details as different wavelengths of light emitted by stars.
Hall comments: “With universities building very large telescopes, like the Keck Telescope, they’ve closed down a lot of the smaller observatories to save money, so observing time on telescopes is actually decreasing for astronomers. This observatory will help to correct this problem, and we have already been approached by professional astronomers from abroad to carry out work for them. One project we will be involved in is an international observation of an X-ray star, and another may entail looking at stars similar to our own Sun to learn how our solar system has evolved. Research projects will be overseen by Richard Dodd, Carter’s leading professional astronomer.”
Public interest in astronomy shows no sign of declining. The Wairarapa facility will allow the people of the lower North Island to experience astronomy, not just read about it.