I joined Dr. Peter Jenniskens, a noted meteor storm expert and a staff member for SETI, on Thursday night, August 11, at Fremont Peak State Park to watch and record the annual Perseid shower. As predicted, the first quarter moon was down by 11 pm and a low fog had dimmed the bright lights below. It was a warm, beautiful night and the skies above were dark. This made for a brilliant display of each meteor zooming by whether bright or faint. It looked like diamonds displayed against a black cloth at a jewelry store.
We set up our equipment next to the observatory where Peter assigned me to survey and record an area within the south eastern sky. I brought with me my recently redesigned Image Intensifier recording system. My new system consists of a Lens, Image Intensifier Tube, Control box, and a Canon ES2000 Hi-8 Camcorder. At the spectacular November 18, 2001 Leonid shower, I had used a 50 mm. f/1.4 lens, although with very successful results, provided only a 22-degree field of view. It now has a wide angle 24 mm, f/2.8 lens which provides a field of view of 60-degrees (almost eight times more coverage). The Canon ES2000 Hi-8 camcorder displays a recordable time down to a second for ease in logging meteor sightings.
Originally I had developed the Image Intensifier system for the 1977 Total Solar Eclipse in Colombia, where I attempted to capture the faint, but illusive "Shadow Bands." For those unfamiliar with this phenomenon, the bands normally appear a few moments before and after totality. Visible to the naked eye as fast moving light and dark bands along the ground or wall surface, they are much like those seen on the bottom of a swimming pool when the surface water has been disturbed. I have since found that my Intensifier system works well for recording meteor streaks.
The Image Tube was discarded by our former companies' Low Level Light TV group, because of the burned spot near the center. The tube is a micro channel high gain amplifier with a brightness gain of 30,000 and a nominal magnification of 1. The minimal resolution is 30 line pairs/mm. The unit has fiber optic input and outputs and is essentially a bundle of micro miniature photo-multiplier tubes. It electronically multiplies the input image by a gain factor depended on the applied voltage-in this case 7 kV obtained from a high voltage power supply operating from two "AA" size batteries located in the control box.
The fun begins when reviewing the Hi-8 tapes on my TV screen and looking for the bright and faint streaks to show up. During the course of the Perseid storm night I recorded over 150 meteors consisting of 25 bright displays, the remainder between faint and medium traces and 6 strays. The count is not complete as I continue to find more faint traces.
Dr. Jenniskens predicted elevated rates around 1:18 a.m. PDT and again later in the night. The results from one camera alone are not enough precise to measure that. We are waiting for the results of three other intensified cameras operated by Dr. Jenniskens, as well as four other cameras operated by amateur astronomers David Holman and Peter Gural at Susanville and near San Diego, respectively.
Many thanks to my personal editors, Joe Heim and May Coon, for reviewing this text and to Dr. Jenniskens for his review and also his guidance and teachings at our site. I also wish to acknowledge the help I received from SJAA President Mike Koop and FPOA Director of Instruments Ron Dammann for making this endeavor possible.
Previous | Contents | Next