With a 3:00 am wake-up call, we left the hotel at 4:00 am on Thursday, January 14 for the peak of Mount Haleakala. On the way up I noticed that the bus' windshield wipers were on and became concerned that we wouldn't see anything. It was not a problem; we were passing through a cloud. Astronomers (on top of mountains) like clouds. They block out light from the cities below. After 29 switchbacks as we worked our way up the mountain we reached the summit at about 6:00 am. The temperature was 3° C. Clearly visible: the Southern Cross, Mars, the constellation Scorpio (the scorpion), and two passing satellites. The picture above, Haleakala sunrise.
The Panoramic Survey Telescope And Rapid Response System (Pan-STARRS) is used to survey the sky searching for objects on a trajectory that will impact the Earth. The telescope design is such that it can view a large portion of the sky. Large enough that it can scan the entire sky visible from its location three times during the dark nights of each month. Successive scans are compared looking for objects that have moved and then their paths are calculated. This telescope is the first of a planned four. Here is a picture of the control room for the telescope. Off to the right in the room was a pile of containers labeled 'emergency food supply'. A few minutes earlier, the monitor on the left showed the astrophysicist who was using the telescope in his warm office at sea level on one of the islands.
When you first look at the telescope this is what you see.
Here is what is actually going on. The primary mirror is a 1.8 meter (6 feet) diameter circular concave mirror with a large circle cut out of its center.
Light is reflected from the primary mirror (in the picture above) to the convex secondary mirror above (shown in the picture below). It is a little difficult to pick out the secondary mirror due to collimating cylinders and reflections. There is a large circular aluminum plate in the center of the mirror.
Then light is reflected down through the hole in the primary mirror to 'the business end', the charge coupled device (CCD) detector. The 1.4 billion pixel detector is about 40 cm by 40 cm. For comparison, your typical digital camera detector may have about 5 million pixels and be a few millimeters on a side. Actually, the detector consists of 60 CCDs arranged in an 8 by 8 grid with the four corners removed. You can see lots of familiar orange fiber optic cables coming out of the detector.
That was just the first event of the morning. The next event was a bicycle ride down the side of the volcano. The bus took us down from the telescope at 9740 feet to our point of embarkation at about 6500 feet, but still above the clouds! Only about a half dozen of our group participated. We did sign a long release form. Some of the rules: follow the lead bicycle, stay in the center of the lane, keep the double yellow lines on the left, keep the single white line on the right, maintain your distance behind the bicycle ahead of you, .... We were told, when using your brakes remember: right R is for rear brake and left L is for launch.
The lead cyclist was in radio contact with driver of the van with the trailer behind us. At times we pulled off the road to let cars pass. There was one uphill stretch. We were told, start pedaling at the bottom and you'll make it to the top. The were lots of places where it was steep and many tight turns. We made one stop, for breakfast. We didn't go all the way down to sea level. Before we got down to an area where there was heavy traffic on the roads we stopped. We covered about 15 miles. At the beginning I was using the brakes even on the straightaways; by the end I was crouching down to minimize my air resistance. Really neat.
We were dropped off at the Maui Ocean Center and the rest of the group joined us there. The main attraction is The Hawaiian Aquarium. There were some interesting examples of sea life camouflage, a flounder (flounder lie on the bottom) that blended perfectly with the surrounding sand and a crab that carries pieces of coral around on its back. There were these interesting unicorn fish. While lots of people have theories, no one really knows what evolutionary purpose the horn serves. When they fight they use sharp scalpels in their tails. We ate lunch at the aquarium. I had mahi mahi, again. We saw green sea turtles. So named because their meat is green. A demonstrator explained that they have young turtles on exhibit, but when they reach maturity they are placed in the ocean. We learned that on Hawaii more people die each year from falling coconuts than from sharks. It was funny; when we were lining up at the group entrance to go in to the aquarium our Tour Manager asked, "How many are not seniors?"
The lecture for the evening was Target Earth. We learned more about asteroids, made mostly of charcoal and stone, and comets, made mostly of ice. Asteroid Ida has a satellite, Dactyl. Comet Shoemaker Levy's 1994 Jupiter impact is well known. In 2009 an impact zone was detected on Jupiter indicating another collision. Asteroid Apophis will make near Earth approaches in 2029 and 2036 and there is some discussion of mitigation missions.
Tomorrow, bags outside our doors at 6:00 am. 9:30 am flight from Maui to the island of Hawaii.
