Astronomy/Moon Libration

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Expert: - 2/28/2011


Question
I understand that Libration allows us to see a total of about 9% of the far side of the moon, but what are the individual percentages of the far side of the moon that longitude, latitude, Diurnal and physical Libration allows us to see?

I've done many Google searches for this information with no results.

Answer
Hi Tim,
Yes, I also can find nothing on the longitudes or latitudes either, but I do know that we're only talking a few percentage points (2-3%) over the eastern and western limbs, and due to perturbations (nodding) and parallax (where you're standing on the Earth's surface accounts for a few extra square miles of lunar surface too, at the poles); that gives us a few percentage points over the lunar north pole and south poles, at different times, too.
So like you said, we can see up to 59% and only 41% is forever out of our view, and is called the back side of the moon (NOT the dark side... there is no 'dark' side).
Actually I'm not into the moon... being a deep sky observer, we really hate the moon... just another big light polluter in our night sky.
See
http://en.wikipedia.org/wiki/Moon
under "Tidal Effects".
Sorry, that's the best I can do for a subject, or rather a night sky object, that I absolutely hate.
Clear skies,
Tom Whiting
Erie, PA  

Astronomy

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Tom Whiting

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Astronomy has been my hobby/pasttime for over 50 years.  Currently own 3 telescopes, the largest of which is a 30 inch Newtonian truss Dob that is portable.I taught Astronomy/Meteorology at the University Level for 13 years before retiring in 1995. Being retired and home most of the time, I am able to answer all questions relatively quickly, unless it's a new moon weekend with good observing conditions.  No astrology questions please, or questions about alleged UFO picture identifications.

Experience

Experience: Astronomy has been my hobby and study for over 50 years. We currently now own a 30 inch portable telescope (Updated - Pennsylvania`s largest portable telescope). It can be seen on our website at:http://www.velocity.net/~bwhiting and also attend several regional starparties during the year, and have been on 5 total solar eclipse expeditions.

Organizations: President, Erie County Mobile Observers Group for over 15 years.

Publications: Wrote the "Over Erie Skies" newspaper article in our local newspaper for 11 years (1975-86).

Education: Masters Degree- Taught at the University level for 13 years. Retired 20 years -USAF Pilot - KC-135 with 180 combat missions;  Also Eagle Scout, Philmont staff 2 Yrs, Order of Arrow Lodge Chief, Ham Radio (inactive).

Awards: two discoveries: The mini-coathanger asterism in Ursa Minor (the little dipper) And the mini-ladle- another asterism in the bowl of Ursa Minor. Clients: Currently President of the ECMOG as mentioned above.

Education/Credentials
BS  Metallurgical Engineering Grove City College, PAMaster's Degree, Gannon University, Erie, PA Also retired USAF pilot, 20 years.

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