Douglas will be focusing on conveying a
basic understanding of comet orbits, using real examples in historical
context, including comets in elliptical, parabolic, and hyperbolic
orbits, and showing how energy concepts can be use to characterize
comet orbits.
Examples will include some of the great
comets of history, such as the Great Comet of 1577, the Great Comet of
1680, and Halley’s Comet, as well as some illustrative recent comets,
as a prelude to a discussion of the hyperbolic orbit of C/2012 S1 ISON.
Will ISON survive solar passage?
Using mathematical modeling software,
Doug will compare the orbit of ISON with some famous “sungrazing”
comets to help explore this question. ISON will in fact reach
perihelion November 28, about 10 days after his talk, so the topic
will be timely!"



Douglas W. MacDougal, an RCA member,
observed his first comet at the age of six and has been hooked on
astronomy ever since.
Some of his memorable experiences
include seeing brilliant Comet Bennett rise with its glorious tail in
the predawn skies over Koko Head crater in Oahu, from the beach where
he was to meet his wife a week later; drawing Comet Halley from his
backyard scope as it steadily approached perihelion; and photographing
the unforgettable Comet HaleBopp with its twin tails from the
stunning 10,000’ skies of Haleakala, in Maui. 
Douglas has a degree in mathematics, with
a minor in physics, from the University of Vermont, and is an adjunct
professor at Portland State University teaching celestial mechanics
and (previously) astronomy.
Doug has taught courses in astronomy
and mathematics in Portland's Saturday Academy, whose classes
typically include talented middle school and high school students.

