Tuesday, July 4

Maungatea's mysterious basalt boulder

Hmmm. Loooooong time since I added anything to RaroLens.
That's because most of my videos these days are of various travel destinations so I've decided to put them on a new blog:
But today I have a Rarotonga-based video so here it is.
A group of friends recently hiked up to Maungatea Bluff, heading into the hills on the northern side of Rarotonga.
We were going to see a strange basalt boulder that Gerald McCormack, the director of the Cook Islands Natural Heritage Trust, found a while ago.
This boulder had tumbled from the bluff down the side of the hill and come to rest a short way off the side of the track so wasn't particularly easy to see if you didn't know it was there.
There are lots of basalt boulders up there but most of them are breccias, conglomerates made of basalt rubble held together by molten lava pouring over them.
The mystery boulder has a series of parallel grooves with rounded bottoms along its surface and on Rarotonga there's nothing else like it that anyone knows about.
Gerald wanted to re-visit the boulder to take more photographs and we all tagged along.
He originally thought the grooves might be man-made but after a lot of online research he found similar rocks in New Zealand, in particular at the Wairere Boulder Nature Park in Northland.
Geologists say these were formed when rain dripped from trees onto humus on the ground. The humus acidified the water which then formed streamlets that ran down the face of the rocks. Over millions of years the water dissolved the rock to form grooves (often called flutes).
There may be other fluted boulders somewhere on the hillside or possibly even signs of flutes up on the bluff but the ground isn't easy to walk over. We were on a track and it was quite a scramble in a lot of places. It's not surprising, then, that nobody has reported seeing anything similar on Rarotonga.
It was lovely being up in the bush but not particularly peaceful. The squawking sound you can hear on the video is the sound of birds, I think they are petrels, flying back from feeding at sea which they apparently do around midday.
Flying is clearly the best way to get to and from the bluff.
We had to walk, make that scramble, back down.

Sunday, January 1

The Golddigger Trail


While we were in Chile tweaking the settings of Phil's remote telescope(El Sauce Observatory), we stayed at the Hacienda Los Andes.
The Hacienda is in the valley of the Hurtado River at the southern end of the Atacama Desert in the foothills of the Andes. It is well away from the usual tourist routes and surrounded by pure wilderness although the valley itseld is green and fruitful.
The lodge grows much of its own food and has hiking trails and is a centre for astrotourism as it has several observatories on the property.
It also has a small herd of Chilean Criollos horses and has horseback riding tours ranging from half a day to multi day expeditions where you can spend up to 5 days in the saddle with overnight camping under the stars.
Well, I've only been on a horse once and that was fifty years ago but the Hacienda can cope with rank beginners as well as experienced riders so I decided to tackle the Golddigger Trail, a three hour morning ride.
My horse, Sirius, was very placid and new the trail intimately. I just had to sit on his back and hold the reins loosely. He had a tendency to stop and pull up clumps of grass to chew as he ambled along but he was the ideal mount for a non-rider.
It was a fascinating ride; once you leave behind the Hacienda environs you are out in rugged country with not a sign of human habitation.
The trail is narrow and winds alongside steep sided canyons, through dry riverbeds and over rocks and sand. Vegetation included cacti, lotsof them, and trees, shrubs and grass that were all so dry that they looked dead but must get enough rain during the winter to keep them alive.
We stopped on top of a ridge for a drink of water. This is supposed to be where an abandoned goldmine was situated, hence the name Golddigger trail, but I saw no sign of anything there.
Thought I might be a bit saddle sore at the end of the ride but I wasn't at all. This is obviously thanks to Sirius - the ideal horse for a beginner.

Telescope in the Atacama Desert


Since retiring Phil's been hankering after a remote observatory.
When we first came to the Cook Islands over thirty years ago it seems that the night skies were clear and the Milky Way looked magnificent for most of the year. I'm sure that's an exaggeration; you remember the things you want to as time goes by. But certainly the sky at night is much cloudier than it was when Phil first built a telescope on Rarotonga. That's global warming in action at the local level.
It's been a long time coming but at long last Phil's telescope in Chile has seen first light.
The observatory is situated at the southern end of the Atacama Desert, 1600 metres high, in an area called El Sauce.The site is home to several other telescopes including four large domes owned by a group of Russian astronomers who also have air-conditioned containers with living, office and storage quarters. Phil's telescope is the first of what will eventually be six set up in a large shed with a roll-off roof. Another much smaller shed nearby has several small telescopes used for tracing space junk. And site has room for more observatories of varying sizes.
Electricity shouldn't be a problem as there's a large array of solar panels with plenty of room for more and, along with clear skies at night, the Atacama has lots of sunshine during the day. Not all the time though - about 330 days a year!
The scope has has been operational for a few months now but needed some extra bits and pieces added to it so we had a holiday that included flying to Santiago, Chile's capital, and then La Serena, a forty-five minute flight further north.
Hired a 4WD SUV iin La Serena and drove to Hurtado, the town nearest the site. The 4WD was necessary because most of the roads we were on were one lane dirt with occasional passing places as you can see in the video.
It was quite an adventure, but the thing about adventures is that they're usually uncomfortable at the time otherwise they'd just be called 'travel'. It was hot during the day but one night we stayed at the telescope and boy was that cold! At 1600m above sea level, when the sky is clear the temperature drops like a stone. During the day the wind howls around the various observatories, because of thermal currents. At night the temperature falls and the winds die down. This means that very early morning is the only time to fly the drone to get some aerial footage, so we were up before dawn and wore layers of t-shirts, jumpers and jackets to ward off the chill. Also needed to keep the drone and GoPro batteries in pockets to warm them up before they would operate.
Living in a tropical island paradise, you forget what really cold weather is like!