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Image of the Month
CCD IMAGING with Adam Block
I arrived at the Visitor Center at around 8:30. Adam Block was assisting the visitors under the dome. They were observing Saturn, which was favorably placed, almost on the meridian. I heard a lot of "oohs and ahhs" as various visitors stepped up for a look. Adam told me that he was using a TeleVue 20mm Nagler eyepiece, which gave a magnification of 203X, with a field wide enough to take in all Saturn's moons. After the last visitor stepped away from the telescope, I stepped forward to take a look. The view was memorable. Seeing was steady and Saturn's image was crisp. The rings were nicely inclined toward us, and I could see the Cassini division right at first glance. The A, B and C rings were very clearly delineated. There were subtle belts on the disc, and the polar cap was a bluish-gray. The colors were quite vivid. The moons Dione, Enceladus, Rhea, Tethys and Titan were clear and sharp. It was a great way to start the evening!
After the last visitors had cleared the dome, Adam and I got ready for another night of observing. Things went very smoothly, and by midnight, I had completed the last object on my Herschel 2 "target list". I'm sure Adam was glad when he learned that I'd observed the final target on my observing list. I had the feeling that he'd been itching to show me the wonders of the electronic imaging world. Sure enough, during our midnight "lunch break" in the astronomer's dining facility, he casually asked if I'd like to see how a CCD camera worked. Actually, I had been curious about CCD imaging, and had from time to time considered poking my toes in the CCD water, but the entrance fee was pretty high, so I kept putting it off. Now, I thought, might be the time to see what electronic imaging was all about.
I watched with great interest as Adam removed the visual star diagonal and eyepiece from the scope and inserted the SBIG (Santa Barbara Instrument Group) ST-8 CCD camera and filter wheel. He then had to connect the camera/filter wheel to the computer that controlled the telescope, and start up the camera control program which was called CCDOps (this was a proprietary camera control program developed by SBIG. It was very clunky to operate, and has long been obsolete...but in 1999, it was "top drawer"). Once he had the camera connected and started up, he slewed the scope to a selected star and proceeded to focus the camera. Once this was done, we selected a target object, in this case the open star cluster M-67 in Cancer, since it was near the meridian.
I should mention at this time that the 16-inch SCT did not have a guide scope, so we were not set up to do guided photography. For this reason, we were limited to fairly bright objects, such as open and globular star clusters. Over the next several hours, we took a number of exposures, usually around 30 seconds in length. At the end of the evening (or I should say EARLY MORNING!) we had imaged 6 objects. After taking 20 or 30 short exposures of each object, Adam then stacked them and did a basic "stretch" of the image to bring out more detail.
When Adam and I shook hands and parted ways just before sunrise, he gave me a floppy disc containing the images, so that I could process them further in PhotoShop when I got home. I look at those images today and laugh at how crude they look! Lots of egg-shaped stars, and lots of electronic noise. But, at the time Adam and I were taking them, I was thrilled by what we had captured in such a short exposure, compared to film!
I went back to my room at the dorm and promptly collapsed into the bed. Lack of rest from the busy schedule had caught up with me! I was out like a light, and slept until just past noon. After waking up, I went to the dining room for a late lunch and then returned to my room to pack. After leaving my room, I stopped at the Visitor Center, turned in my room key, and started down the mountain. As I drove towards Tucson and Kitt Peak receded in my rearview mirror, I felt a deep sense of satisfaction. THOSE TWO NIGHTS ON KITT PEAK WERE AN UNFORGETTABLE EXPERIENCE.
A FOOTNOTE: My short initial exposure to CCD imaging with Adam Block planted a small seed in my mind that began to bloom a few years later, after I had built Land of Oz Observatory.
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