90-minute exposure of stars over Mt Taranaki, Egmont National Park
This photograph is the result of an idea that struck me whilst travelling from Palmerston North to New Plymouth one night back in my student days. I had seen time-lapse photographs of stars before, but I was curious as to how such a photograph could be taken so that the stars centre of rotation, the South Celestial Pole, would be directly over the top of a prominent natural landform, such as Mt Taranaki.
A few years later, in October 1999, I decided to try it out. Simple geographic principles told me that, to get a photograph with the stars rotating about a point directly over the summit of Mt Taranaki, I had to get to a south-facing vantage point that was exactly north of the mountain. By drawing a few lines on a topographic map I found a suitable point to be on a spur just below 1399-metre Henry Peak, on the Pouakai Range immediately north of Mt Taranaki. With good weather in the forecast, it was time for me to go and see if my idea would actually work.
On arriving at my pre-chosen spot near Henry Peak I found it to be covered with thick scrub vegetation, making a photograph impossible. However Henry Peak itself, about 300 metres to the northwest, was mostly open tussock, so this became my vantage point after a short extra climb. (This is also why, if you look closely at the photograph, the South Celestial Pole is not quite directly over the mountains summit, but offset to the right just a little).
Compared to the effort involved in lugging my gear to this point, the photograph itself was not difficult to get. Once it was dark I simply opened the shutter, locked the cable release, set the alarm on my watch for 90 minutes and got into my sleeping bag to wait. For most of this exposure I was in fact fast asleep!