Observing the heavens from the summit of Mauna Kea
Hello, I’m Dr. Missagh Mehdipour, a research scientist at the Mullard Space Science Lab. In this post I will tell you a little bit about my first observing trip to a telescope.
As an X-ray astromoner, I am interested in studying the hottest objects in the universe which radiate in the X-ray energy band. However, as a consequence I don’t often travel to ground-based telescopes to observe them; X-ray astronomy can only be done from space since the Earth’s atmosphere absorbs the X-rays (on the upside those harmful radiations cannot reach us!). So when in the final year of my PhD the opportunity of an observing trip to a ground-based telescope came along, I grabbed it with both hands. My colleague Prof. Mat Page, and I travelled to the James Clerk Maxwell Telescope (JCMT) on the summit of Mauna Kea in the Island of Hawaii.
With a diameter of 15 m, JCMT is the largest single-dish telescope in the world operating in the sub-millimeter region of the spectrum. With its sensitive instruments it detects light from the coldest materials in the universe, with temperatures of only a few degrees above absolute zero. The observations that we carried out were part of a major survey to study our galaxy and the universe in sub-milimeter wavelengths. Since water vapour in the Earth’s atmosphere attenuates radiation in this part of the spectrum, the high altitude and dry conditions of Mauna Kea (an extinct volcano standing at 4200 m above sea level), makes it the ideal place for submilimeter astronomy. In fact since the creation of an access road in 1964, more than a dozen world-class telescopes have been constructed at the summet, making Mauna Kea one of the most important sites for ground-based astronomy.
Atmospheric pressure at the summit is about 40% less than at sea level; this poses a health risk which can have a range of effects on humans from minor discomfort to life threatening conditions. Therefore we were strongly adviced about sympotoms of altitude sickness and how to prevent it and respond to it. Before travelling to the summit, we stayed at our base camp (known as Hale Pohaku, Hawaiian for “stone building”) on the slope of Mauna Kea for two night to allow us to acclimate to the high altitude. Hale Pohaku at an elevation of 2800 m is a cluster of buildings which includes few dormetories and a main building containing a caferteria, offices, recreation facilities. The many cinder cones and lava rocks in the surrounding areas are testement to the former volcanic activity of the mountain.
Our observing program ran for 7 consecutive nights; we would leave our base at 6 pm each night and return by 8 am the following day. After the first two nights, staying up all night became easy! For safety reasons, no one is allowed to spend more than 14 hours above the base camp in a 24 hour peroid. The drive from Hale Pohaku on the winding dirt road to the summit takes about 20 minutes. The view from the top is spectacular; we often saw tourists driving up the mountain to catch a glimpse of the beautiful sunset.
In the couple of days we had before and after our observing run, we visited some amazing places in the Big Island. One interesting location is the Volcanoes National Park. The park is full of mind-bogglingly huge crators and fascinating lava fields. The cracks on the ground from which steam and sulphur gases are expelled are a reminder the region is an active geothermal area. The diverse and beautiful landscape of Hawaii Island makes it a unique place definately worth visiting!