Telescope Reviews: observing Comet 2P/Encke

The easiest way to answer this is to look at the published ephemerides at the Harvard IAU site

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/0002P.html

Two things to look at are solar Elongation and estimated magnitude (m1). During its 40 month orbit it is typically only visible to amateurs for only 3 months (mag < 14). The magnitude typically ranges between 5.0 and 22.0, with 37 months typically below mag 14.

However during the next apparition in August 2010 the comet will peak at mag 5.0 BUT it will only have a solar elongation ranging between 1.3 degrees and 10 degrees during its brightest phase. This will make it impossible to observe in any useful way - except during the total solar eclipse! There are periods either side of peak brigness where the comet reaches a useful elongation but is either rapidly brightening or dimming in the 11.0 to 7.0 mag range. So there are observing windows. Overall this is a very poor apparition indeed!

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Televue 85, GM-8/Gemini, Canon 40D (unmodded), Canon 450D (modded w/Astronomiks clip-ins - UV/IR, OWB)
Coronado SM60/BF10, Baader Herschel Wedge
Leeds Sky Clock Ripon Sky Clock