Flamsteed Astronomy Society

NMM Member Event September 21, 2008 — Fred Watson

“Navigation & the Inter-planetary Superhighway”

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by Mike Dryland

Fred Watson is Astronomer-in-charge of the Anglo-Australian Observatory at Siding Spring NSW.  Fred presents a very popular radio show down-under and has become the public face of astronomy in Australia.   He is author of the best-selling books “Stargazer: The life and times of the Telescope” and “Why is Uranus upside down?”, a Q&A collection based on his radio show.  Fred was leading a whistle-stop tour of locations with astronomy connections in Europe in celebration of 400 years of the telescope, and we were lucky to catch him when he could lecture at the NMM.

Fred’s subject was “Navigation and the Inter-planetary Superhighway”.  He began by looking at navigation on Earth — a Great Circle route is the shortest path between two points, but navigators often don’t follow great circles.  Other routes are sometimes quicker or cheaper.  Since the days of sailing ships, navigators have depended on ocean currents and the trade winds, and now in the time of jet airliners, the jet-stream, which can give a boost in speed of very many KPH, often determines the fastest route in practice.  So it is in space.  Fred followed the history of learning about the dynamics of space travel and showed how navigation between the planets shares many similarities with terrestrial travel.

Fred’s style is very fluent and entertaining.  He constantly digresses on tangents from his main theme, somehow returning unerringly to where he left it.  His narrative is spiced by anecdotes and asides with lots of laughs, and he makes astronomy highly accessible without being condescending.  It’s very easy to see why he’s so popular on radio and TV.

Fred Watson (pic: Mike Dryland)

Navigation on Earth — Great Circle route.  Shortest but not necessarily quickest or cheapest

Fred works his way from Newton’s laws which describe how gravity works, same for the Moon and apples, and looked at escape velocity and orbits.   In navigating between planets, the ‘transfer ellipse’ or Hohmann orbit is the equivalent of the Great Circle on Earth.  On the way, Fred took us through a review of Mars exploration looking at the Mars Rovers, and Phoenix mission, with even a nod at Beagle II. 

The  ‘Transfer ellipse’ or Hohmann Orbit — space equivalent of the Great Circle.  The shortest and fastest way to travel from planet to planet, but very expensive on fuel.

Fred Watson

(pic: Mike Dryland)