Comet Chasing The visual observation of telescopic comets as if they are moving deep sky objects
Most people see the big bright comets, but relatively few track down the telescopic ones
How I became a Comet Chaser Comet IRAS-Araki-Alcock came within 0. 03 AU of the earth in 1983. This 3 rd magnitude comet moved 30 degrees across the sky in one night. The 21 -inch Visitor’s Telescope at Mount Laguna Observatory
The First Information Revolution • Software to plot comet positions was the 1 st revolution • Knowing only the position of a comet isn’t enough • The visual magnitude doesn’t reliably tell you if a comet will be visible in the scope
Size Matters Why did I fail to observe the 12 th magnitude 2 P/Encke in an 18 -inch Dob?
DC Explained • The Degree of Condensation is a measure of how diffuse the comet appears • DC = 9 is starlike • DC = 0 is uniformly diffuse • The more diffuse, the more difficult it is to detect for a given magnitude
The Second Information Revolution • Recent comet observations available online • Magnitude, Coma Diameter and DC synthesized at my Comet Chasing web site • Minimum aperture for detection can now be reliably estimated
How I Estimate Comet Detectability 1. 2. 3. 4. 5. My Sky. Tools software uses an algorithm based on the work of Dr. Bradley Scheafer to estimate how difficult it is to detect a star in a telescope My software similarly uses a detection contrast algorithm based on the work of Roger Clark and Mel Bartels to estimate how difficult it is to detect a diffuse object in a telescope Both algorithms model the eye, optical system, atmospheric conditions, light pollution and the astronomical object Both algorithms estimate a detectability parameter that can be characterized as obvious, easy, detectable, difficult, challenging, very challenging, or not detectable I compute both detectability parameters for the comet and then interpolate based on the DC to obtain a best estimate of the detectability of the comet
My Comet Chasing Web Site cometchasing. skyhound. com The minimum aperture required is broken down into the following categories: naked eye, 7 x 50 binoculars, small scopes (4 inches or smaller), various intermediate apertures, and very large scopes (24 -inch or larger).
Successful Comet Chasing 1. Start by finding out which comets should be visible to you at cometchasing. skyhound. com 2. Use any software to plot the position 3. A dark site is important 4. Have an expectation of how large the comet will appear in the eyepiece 5. Start with your lowest-power eyepiece unless the comet is small
The Fun of It With the right information Comet Chasing is no more difficult than observing the Messier objects But why chase them? • Comets change from night to night • Periodic comets form a link to our own past and that of observers from long ago • Comets lead us into interesting star fields we might not otherwise see
Comet Chasing Resources Comet Chasing cometchasing. skyhound. com Comet Observing Information www. aerith. net Cometography by Gary Kronk (historical comets) www. cometography. com Comet Chasing Group groups. yahoo. com/group/Comet. Chasing
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