published North and South 1997
A chilly late autumn night in a Marlborough vineyard. Outside the magic of the sky awaits and grape grower and astronomer Bill Allen steps out of his warm house and into his observatory. He is going to observe and record the dance of the variable stars.
Bill built his first telescope when he was studying electrical engineering at Canterbury University in the 1960’s and has been hooked ever since : “I still find the sky fascinating. Sometimes I will sit outside on a camp chair and just gaze at the sky with binoculars.”
Along with a handful of astronomers in New Zealand and less than 100 worldwide, Bill practices photoelectric photometry – the study of variable stars. There are two basic types of variable star – ones which pulsate, and twin stars which spin and whirl around each other, each masking the light from the other.
The key is the changing light emitted by the stars. Equipment on the telescope monitors the changes in star brightness and this data is analysed by a computer. The electronic signals produced can be played over speakers, so as well as gazing at the skylarking stars , Bill listens to them.
Bill is one of many backyard astronomers who form a network known as ‘a whole earth telescope’ – a scheme organised by professional astronomers whereby amateurs in various parts of the world observe a particular celestial body as the earth turns.
A highlight of Bill’s astronomy career was his involvement in the discovery of Pluto’s dense atmosphere. In 1988, a planetary occultation (a planet moves in front of a star and blocks out its light) involving Pluto occurred.
“Pluto passed in front of a very faint star and for a period of time, blocked its light. By knowing the speed of the planet moving in front of the star, it was possible for the first time, to directly measure the diameter of Pluto.
“Before this event, it was thought that Pluto didn’t have an atmosphere, but the way the star’s light faded before and after Pluto passed, indicated an extensive atmosphere many times the depth of the earth’s atmosphere which was totally unexpected.”
So, what makes a man who hates the cold set the alarm, leave his warm bed in the middle of a winter night – “some nights I’d get up, observe, go back to bed and almost not realise I’d done it” – and sit under a frosty dome open to all the elements? Bill and his fellow astronomers use the word serendipity to describe the attraction: “You are looking at a group of objects and you might just discover something such as a star exploding ( a super nova)
“It’s the continually unfolding mystery of the sky, the hope of finding something, the excitement of making a successful observation and the satisfaction of contributing to science.”
Serious amateur astronomers such as Bill are a valuable resource for professional astronomers. Many of the world’s largest telescopes are oversubscribed many times over which means professional astronomers have limited access to them. While the backyard telescope is not able to see the faintest objects, the keen amateurs are able to spend many hours keeping an eye on what is going on.
After 30 years of observing the heavens, Bill says they still capture his imagination although he always applies strict scientific principles to his observations and he has never seen an unidentified object: “I have spent a lot of time looking at the sky and there’s nothing I can’t explain. I tend to know the sky like I know a city -when something is there that shouldn’t be , I can easily pick it up whether it be a rising star or planet, or a satellite.
“Having said that there have been times when I have been observing by myself on the top of Black Birch ( at the former Carter Observatory outpost) – the isolation gets to you a bit and it’s been almost frightening. If you see something unexpected you get a cold sensation up your back but then you identify it and you’re O. K..”
As well as practising the ancient science of astronomy, Bill dabbles in another age old tradition – viticulture. About four years ago, he and his wife Rosemary moved out of town into the Marlborough countryside and developed an eight hectare vineyard with the help of their horticulturalist son, Tim. They grow eight hectares of sauvignon blanc grapes (63 tonnes produced last year) for Villa Maria. Bill’s scientific approach has paid dividends here as well, as last year’s crop from the Alvine Estate produced a gold medal wine for Villa Maria.
The Allens are not the first to combine astronomy and viticulture in New Zealand. Back in 1842, the French Mission Brothers established the nation’s first winery in the Hawkes Bay and erected a telescope in the vineyards in 1909 – just in time to see Hayley’s comet .
“I’ve got the best of both worlds here. The atmosphere is clear with no electric lighting from the town which is great for astronomical viewing, and the vineyard is a retirement project for the family,” Bill says happily.