On a sub-zero June night, more than 150 of us are ferried in and out without the use of any white light, which would interfere with the research telescopes. Bus lights are turned off, cellphones and torches are banned, and all visitors receive a red-light key ring from the Earth & Sky offices.
As one infectiously enthusiastic guide points out, man will be colonising Mars within the next 100 years. And Mt John will arguably be the best spot in the Southern Hemisphere to watch their progress. It is home to the largest telescope in New Zealand, the Moa Telescope, which in 2008 discovered the smallest known planet outside the solar system.
As the Earth & Sky guides describe the farthest reaches of the universe, cheerful assistants bring out steaming hot chocolates to keep the Southern Alps temperatures at bay.
"We'd be arrogant to think we're the only ones here," says one star-gazing guide, looking out at the endless expanse.
Nestled in the Mackenzie Country, with its sweeping shades of blue, green, brown and white, Tekapo has always been a pleasant stop-off point between Christchurch and Queenstown. Tourists have long made the pilgrimage to take a photo at the Church of the Good Shepherd on the banks of Lake Tekapo.
But for those with more time on their hands, there are plenty of activities at this lakeside resort town.
Maori call the area Takapo, which means "To leave in haste at night". But at Peppers Bluewater Resort, the day starts with a picturesque sunrise over Lake Tekapo.
With the breakfast smorgasbord feast out of the way, most winter travellers will make tracks for the snow at Ski Roundhill 35km up the road.
Roundhill has a reputation for being family-friendly and a great place to improve your skiing skills.
If, like us, you find the snow isn't playing ball, plenty of other activities can be found to keep you busy.
Head over to the hot pools at Tekapo Springs. Arrive early enough to beat the masses and may just get one of the three pools to yourself.
The steaming pools range from 36C to 40C, or if you want to experience lake temperatures there's a plunge pool at 8C, and an ice skating rink. The springs are surrounded by snowtopped peaks and just a few hundred metres from Tekapo township.
A well-informed local tells me that Twizel, just up the road, is the wife-swapping capital of the South Island.
But for more conventional swingers, The Cairns golf course is a great way to spend an afternoon.
Grab a buggy and head to the front nine, with the Southern Alps in view to inspire your shotplay. Make sure you bring plenty of golf balls, as the water hazards are numerous.
If you still have some breakfast bacon butties to burn off, the fantastic walking tracks on the southern approach to Mt Cook are just 100km away. An hour and a half's hike through glorious alpine country along the Hooker Valley Track takes you to the south face of Mt Cook/Aoraki and an iceberg-strewn lake.
On the drive back to Tekapo, be sure to pick up a couple of freshly caught salmon steaks at one of the numerous salmon farms.
Back at Peppers Bluewater, you could inquire whether sous chef Jose is available to whip up a salmon feast.
We were lucky enough to experience a three-course meal: starter of filo pastry tail of salmon with pine nuts and grapes.
Next up was a three-part entree of poached salmon, salmon fishcake and gravlax. Then for the main, grilled salmon on soba noodles, artichokes and bok choy, all washed down with a local chardonnay.
No one will be leaving in haste this night.
Bevan Hurley visited Lake Tekapo courtesy of Peppers Bluewater Resort, Lake Tekapo. Thanks also to Omega Car Rentals.
