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The Webfooted Astronomer - May 1999
University of Arizona Astronomy Campby Fred Quarnstrom
I recently attended the University of Arizona (UA) Astronomy Camp in Tucson, Arizona. If you ever get a chance to go, it is well worth the $350, which includes food, lodging, and use of 61-inch, 60-inch, 40-inch, 16-inch, and 10-inch telescopes, hydrogen alpha filter, a 2K-by-2K CCD camera, and many two-inch eyepieces. Here's an account of my experience at last year's camp. The camp was the same this year except we had one more day and got to use CCD cameras.
Camp began at the Alumni Association building of the University of Arizona. Our adventure at adult Astronomy Camp began when Dr. Don McCarthy came through the door a with a bright red Edmond's Astroscan telescope under his arm. Don is an Astronomer at the Steward Observatory.
He introduced his camp staff, all graduate students working on their Ph.D.s. They looked like they belonged at a YMCA summer camp staff with ponytails, jeans, and shorts. The campers included housewives, a dentist, a couple of medical doctors, a few wives who came with their husbands, several retired folk, and a school teacher. The common thread was an interest in astronomy.
We were driven a short distance to the planetarium at the Flandrau Science Center where we reviewed directions, meridian, zenith, altitude measurements and were introduced to the stars we would see in the sky later that night. Larry Dunlap did a particularly good job of centering our attention to the square of Pegasus describing it as a baseball diamond and guiding us to areas of interest in left field, right field, and first base.
We next visited the Steward Observatory Mirror Laboratory under the football stadium. They were in the process of polishing a 6.4-meter mirror. It was a little shocking to see one of the technicians walking on the mirror with padded shoes with a push broom cleaning the mirror.
We then saw another 6.4 -meter mirror and 8.4 meter mirror blanks that were waiting for grinding. It is hard to relate to a mirror that is over 27 feet in diameter. Both mirrors had focal lengths of slightly more than their diameter f= 1.25 and 1.14. This lab has pioneered in the use of silicon forms that leave the back of the mirror looking like a bee hive. The open cells are about 6 inches across with walls that are 1/2 an inch thick. The top of the mirror has a glass slab that is about 2 inches thick, the same as my 10-inch mirror.
The form is placed in an oven after being loaded by a borosilicate Pyrex type glass. Once the glass is melted about the consistency of honey, the oven starts to rotate at 7 rpm. This causes the molten glass to climb up the walls of the mold giving it the shape of a parabola. The front surface of the mirror will be within millimeters of the final shape when it comes out of the oven. The oven is slowly cooled until the glass has set. The oven stops rotating at this point and the temperature is slowly brought to room temperature over the next three months. Once the mirror is cool, high pressure water jets are used to remove the forms from the individual cells. The resulting mirror weighs about 1/6 of what a solid mirror would weigh. There I was standing with in touching distance of the largest mirror ever cast.
For the next hour and a half we wound our way up into the mountains north of Tucson to Mt. Lemmon. The summit is relatively flat and 9200 feet in elevation. The summit is occupied by and old Air Force facility, several buildings for sleeping, a kitchen, and a half court basketball court. There are six telescopes at the summit.
At sunset, we first watched the space shuttle and Mir pass overhead and then headed to Mt. Biglow to observe with the 61-inch telescope. There were a number of binoculars and two 10-inch Meade LX200 telescopes for us to use. The 61-inch scope is computer controlled and housed in a dome close to 40 feet in diameter. It has an hydraulic floor that lifts or lowers the observer to the proper height to reach the eye piece. To say we were spoiled is an understatement. We viewed spectacular Jupiter, Saturn, Neptune, Uranus, many planetary nebula, and the Orion Nebula. I actually felt I could see some of the red color you see in photos. Part of the group left for the barracks at about 1 a.m. the rest of us spent the night until the sky was starting to glow toward the East
I got this picture of Mars by holding
Breakfast was at noon followed by a discussion of the emptiness of space and an exercise of laying out a miniature solar system. That afternoon we viewed the sun and solar prominences with an H alpha filter on a LX200 and a projection image from the Astroscan.
Don and his staff were truly amazing with their descriptions. All of them were very bright folks who understand astronomical concepts and are able describe them in ways we could understand without the math and physics calculations that I have forgotten from my college years 38 years ago. They made very complex topics understandable and seemed to genuinely enjoy answering our questions.
Our second night of observing again began by watching Mir. This evening there was also a SBIG ST7, CCD camera set up to demonstrate CCD astronomy. At 1 a.m. I left for the barracks; two all nighters is more than I can handle.
Sunday we packed up and rode back to Tucson. From there it was an hour to the Southwest and Kitt Peak. We visited the gift shop to see the fixed displays. The glass core that was cut from the 4-meter mirror was on display. It is almost 2.5 feet thick. The National Solar Observatory was next. we entered the tunnel that goes many hundreds of feet into the rock to a mirror that reflects and focuses the sun back up the tube to another mirror that directs the image down into an observing room where the image of the sun is about a yard across. The white box behind the blue yolk holds the mirror.
Our next stop was the 4-meter scope. We crawled into the CCD cage. We were shown images of M 33 that were taken the previous night. We saw the aluminizing vacuum chamber, machine shop, and control rooms.
We ended our day watching a sunset and for the first time in my life I saw the green flash. The flash was confirmed by several others in our group. Once the sun was down we had our farewell dinner at the University of Arizona dormitory on the summit of Kitt Peak and started back to Tucson and the real world. What a weekend!
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