HKU Bulletin October 2012 (Vol. 14 No.1)

Cover Story Will we detect anything? Are we going to discover a new phenomenon? Is my theory going to be confirmed? Disappointment will mean an adjustment of plans. A new discovery will lead to excited cheers. ¡ ¢ £ ¤ ¥ A Pilgrimage to the Stars Professor Sun Kwok, Dean of Science, describes a night in the life of an astronomer. are often hung on the telescope high above the ground, we use a ‘cherry picker’ to reach the boxes. Trying to fix delicate things in such clumsy clothing (and often in darkness) is not the easiest job. Close up with the stars If we are lucky, the problems are not major and observation can start. In the old days, one had to constantly guide the telescope to ensure it was not drifting from the target. Now, much of this tedious work has been automated and the computer does the guiding. Many of us still watch the screen for any signs of instrument malfunctioning or abnormal weather conditions. Will we detect anything? Are we going to discover a new phenomenon? Is my theory going to be confirmed? After the exposures are finished, we take a quick look at the raw, unprocessed data hoping for a glimpse of what we are looking for. Disappointment will mean an adjustment of plans. A new discovery will lead to excited cheers, hugs, and sometimes tears. One of my favourite activities is to go out to the catwalk around the dome and admire the glory of the stars in the night. After allowing my eyes to adapt to the darkness (and this is total darkness as there is no artificial light anywhere in sight), I can make out faint stars that are hard to see among the light pollution of our civilised world and enjoy the majestic Milky Way. One has the feeling of being as close to God and nature as one can be. When the dome finally closes with the dawn, I walk out of the building. The shadow of Mauna Kea is projected onto the distant sky by the sun at our back. Despite my tiredness and fatigue, this magnificent sight greatly boosts my spirits. Until I am too frail to undergo the vigour demanded of a night of astronomical observations, Mauna Kea will remain my Mecca and Jerusalem. M acclimatise to the high altitude. My students and I go over the star charts and observing plans, scheduling every detail of the coming nights down to the minute. This is necessary because at the summit of 4,200m, the decreased supply of oxygen can create acute mountain sickness including headaches, drowsiness, nausea, and worst of all for a scientist, impaired judgment. Since the cost of observing time on a telescope is valued at tens of thousands of US dollars per night, one does not want to make any mistakes or waste a single minute. A steep climb After a few hours of rest and breakfast around noon, I head up to the summit to check out the conditions of the telescope and the instrument I expect to be using. Too many times, I have found problems with a failed component, requiring me to make new plans. Sometimes, wind and snow on the summit intervene, creating endless anxiety that my precious observing time may go to waste. The road between Hale Pohaku and the summit is mostly unpaved, steep, and winding, but once we reach the summit, we are greeted with the most spectacular sight of white telescope domes against a background of infinite blue skies. Among the largest are the two 10-metre Keck Telescopes, the 8.3-metre Subaru Telescope, and the 8-metre Gemini Telescope. After checking the equipment, I return to Hale Pohaku for a short dinner, then climb the summit again to start my observation. I turn on the instruments, fire up the computer, and wait for sundown in the small and cramped operation room. This often is the most anxious moment because we will find out whether the instruments are working up to our expectations. If any problem develops, we put on our boots, gloves, and heavy coats and leave our heated control room for the naturally cold dome above. As the instruments o r r l m y m k j p o r q r v k r x y r j v p j j v | u j k s r v v k j w x y z { k | y o m v v p x r y p ¦ m p § k j r m | k { k j | m y n k y y m y v p j x l r y p m y p o r k l r k s p o r y ¨ i j y r ¨ { m m r q r v k r 7KH PDJQL¿FHQW VLJKW RI ZKLWH WHOHVFRSH GRPHV k x j p r v k s y ¨ i j y r ¨ { m m r q r v k r k j As I step off the plane at Honolulu airport, I am greeted by warm tropical air and the smell of the sea. Sun-seekers give me a puzzled glance, wondering what this crazy guy is doing carrying a heavy winter coat in this tropical paradise. Indeed I am the odd man out as I am not heading to the beach, but to a dormant volcano 4,200m above sea level on the Big Island of Hawaii. I will need all the warm protection I can get in the subzero temperatures of the summit of Mauna Kea. Mauna Kea, meaning ‘white mountain’ in Hawaiian for its snow-capped summit, is a sacred site for native Hawaiians. Mauna Kea is also a holy site of modern astronomy. It is the most popular location in the northern hemisphere to place large telescopes for astronomical research. A tropical inversion cloud layer forms around the mountain at about 600m, meaning the summit is almost always above the clouds, resulting in endless clear skies above. I head up the mountain to Hale Pohaku, a mid- level (2,800m) facility for the observatories where I usually spend my first night trying to o r r l m y m k j p o r q r v k r x y r j v p j j v | k x j p r v k s r l m y m v r j p k j 11 October 2012