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Kitt Peak - Part Two
Kitt Peak comes to life at sunset
SpaceWatch domes (left) 4-Meter dome (right)
36-inch SpaceWatch dome
Jim Scotti in the control room
Adding the liquid nitrogen
I was looking forward to the dinner hour, because of an additional contact I had made at Kitt Peak, thanks to my local astronomy club's participation in the NEAR EARTH ASTEROID (NEA) program. One of our members, Larry Robinson, had been in contact with an astronomer at the University of Arizona, Jim Scotti. Jim had received his degree in astronomy from University of Arizona in 1983, and has been active in the SpaceWatch program, a project at U of A that looks for Near Earth Asteroids. He had been involved in confirming a number of NEAs which were discovered by Larry Robinson and Dick Trentman from our club.
Larry had emailed Jim and arranged for him to get together with me while I was at Kitt Peak.
I had been in touch with Jim, and we arranged to have dinner tonight, after which Jim said he would give me a tour of the SpaceWatch 36-inch telescope!
Since I knew that my observing program wouldn't start until after the Public Observing Session concluded at 9 PM, I knew that I'd have plenty of time for my visit with Jim Scotti.
Shortly after arriving at the Dining Room I met Jim and during our meal we had a fascinating conversation about his work, and how he has been collaborating with amateur astronomers such as Larry and Dick at our astronomy club.
After dinner, he took me up to see the SpaceWatch observatory where he would be using the 36-inch that night in his continuing search for Near Earth Asteroids.
On the way, we noticed that, as the sun set, Kitt Peak was starting to come to life. The nearby domes of the 84-inch and the 3.5 meter WIYN telescope were opening up, and the domes were rotating. (see picture to LEFT).
As we continued our walk, the domes of the two SpaceWatch telescopes came into view, with the huge dome of the Mayall 4-meter in the background. (see
picture at left).
The dome of the 36-inch telescope he would be using tonight is shown in the picture to the LEFT.
Upon reaching the dome, we entered the control room and Jim booted up the computer and started the software that would be controlling the telescope.
Once he had the computer and the telescope connected, his next step was to prepare the instrument
and camera for the night's work.
The camera he uses is a very sensitive monochrome CCD detector that is cooled with liquid nitrogen. One of the first things he needed to do was to fill the cooling chamber in the CCD detector with liquid nitrogen, which has a temperature of over 300 degrees below zero.
The 36" Spacewatch scope and its nitrogen cooled CCD camera.
After these housekeeping procedues were done, Jim and I returned to the 36-inch's control room and he completed his set up for the night's work. Jim explained that his Near Earth Asteroid search work employs a technique called "drift scanning". I was unfamiliar with this term, and his explanation was fascinating.
Basically, to "drift scan", the telescope is slewed to the "start point" of the search area, as designated by Right Ascension and Declination angle. Once the telescope is in the "start position", the telescope drive is turned off, and the sky "drifts" through the camera's field of view due to the Earth's rotation. The CCD camera sends a continuous feed of images to the monitor in the control room. It's like watching a slow motion movie, with new objects constantly "drifting" into view at the left side of the screen. The super-cooled sensitive CCD detector shows objects down to 25th magnitude as they drift across the screen. Whenever a fast moving Near Earth Asteroid appears on the screen, it will usually have produced a trailed image by the time it drifts off the field of the camera. The position of any trailed image is automatically picked up by the software and "flagged" with its RA and DEC position for further follow-up and orbit calculation.
I spent several hours with Jim, watching objects drift across the screen: stars, star clusters, nebulae and even galaxies (which Jim referred to as "pests"). He said that it was unbelievable how many galaxies he sees during a night spent drift scanning and said that it only served to increase his awe at the vastness of the universe. Eventually it was almost nine o'clock, and I had to bid farewell to Jim. He was a very friendly and engaging guy, and was a pleasure to spend time with. Thanks, Jim! He showed me to the door of the observatory, and I made my way back down the hill to the Visitor Center to begin my night of observations. I could hardly wait.
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