On the way

We'd visited Tekapo five or six years earlier, driving south from Rangiora on Highway 1, through
Christchurch to Geraldine, then turning west. This time, however, being in convoy with others (a trip
organised by our Probus Club) who knew better, we took the Scenic Highway west through Oxford,
then south to pick up Highway 77 near Coalgate.

Pausing at Geraldine this time, too, (a very pleasant town), for coffee and snack, then continuing
to Tekapo, we checked in to our 2-night stopping place and prepared for our evening at the
observatory on Mount John.

Tekapo, the town, is a pretty place on the south shore of Tekapo, the lake, while Mount John is on
the South West shore of (would you believe) Lake Tekapo.

Mount John is, apparently, technically a roche moutonnee – a rock shaped by glaciers. Its top is at
an altitude of 1,031 metres (3,380 ft) and is some 300 metres (980 ft) above the lake. One of its
claims to fame is that in April 1970 a wind of 250km/hour was recorded (135 knots, 155mph) – the
fastest known in NZ, which is a rather windy country anyway.

The Observatory

Initially a joint venture between the University of Canterbury (NZ) and the University of
Pennsylvania (USA), the observatory was opened in 1965. Shortly after that, the USAF surfaced
the rough track leading to the top of the mount, then built a satellite tracking station – which became
redundant and closed in 1983. The building was modified, incorporated into the observatory and
now houses the largest telescope. From about that time the University of Canterbury have run the
facility.

The site was chosen after extensive surveys of several places on the South Island. The key features
are its high number of clear nights, the stability and transparency of its atmosphere and the very low
light pollution in the Mackenzie Basin. You can no doubt imagine the care taken to minimise the
effect of street lighting in the town.

There are several telescopes installed, the original Cook Astrograph (1936 design) was the first.
More recently the MOA2 (Microlensing Observations in Astrophysics) was installed (appropriately,
the extinct Moa was New Zealand's largest, flightless, bird). This 1.8m telescope is of Japanese
design and has a Russian-made mirror. Its operations involve Nagoya University (Japan) along with
Auckland, Massey, Victoria and Canterbury Universities (NZ).

There's more information
here
and a nice panoramic movie.

Nowadays tours, which include individual observing, are run by a commercial company, at a
cost upwards of $100. Our visit was arranged through the good offices of a club member and an
astronomical friend and it cost us nothing – nothing, that is, except the mandatory visitors' $5 per
head towards road maintenance. The chances are that ours will be the last such visit – they need
whatever revenue they can raise.

Twenty of us, in 5 or 6 cars, gathered at the foot of the observatory road, which is some kilometres
along a side road leading off the highway, at 6:30pm and were led up by the astronomical friend of
our club member.
The ascent is very bendy, with quite steep bits – not a particularly difficult road in daylight, though
not so easy either.

We were expertly hosted by two astronomers, who explained what we were seeing on our several
individual observations as well as giving talks, aided by a laser-pen, at our expected level of
knowledge. The night wasn't as clear as we or they had hoped but the occasional patchy cloud
didn't interfere too badly as there was always a clear space in another direction.

Between us, we saw the Pleiades, Aldebaran, Rigel, Betelgeuse, Procyon, Castor and Pollux.

For me the highlights were seeing Venus looking like a small luminous moon halfway lit and
Jupiter with three of its moons bright and clear.

This observatory, though not one of the world's largest, has some importance as, currently, it is the
southernmost. For a while, until 2005, there was a fully automated site actually at the South Pole
but perhaps unsurprisingly, maintenance problems overwhelmed the project.

The search for extrasolar planets is a major part of the work here and naturally, not infrequently
they get messages asking them to look at specific coordinates 'at something interesting' so that
observations can be made continuously and subsequently collated.

After some five hours, our time ran out. Some of us were disappointed but others not.

We gathered at 11:30 to be led back down the track. By this time, of course, it was dark and
naturally, we had to be careful of the car lights – sidelights OK, headlights NO – not for the first 1/3
or so of the descent.

Manageable ...except for our driver – the dashboard lights didn't dim and he didn't know where the
adjustment was and, dazzled, he couldn't see where he was going on the tighter bends. Our front-
seat passenger sacrificed her cardigan despite the cold so it could be draped to mask the glow.

You're reading this so you probably realise that we got down safely – just a little shaken and, yes,
still starred.

Articles by Rod Archive

Rod

05.03.12 Front Page

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