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Astronomy/Moon & Sun sometimes appear larger than usual

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Expert: - 1/7/2005


Question
Why is it that sometimes both the moon and the sun appear larger than normal?  Is it a function of atmopheric moisture having an magnifying effect?  For instance, early this morning the moon looked VERY large while I was at my home (5:15 AM eastern time)- by the time I got to work (about 35 minutes later) it appeared closer to normal size, but still fairly large.  My home is in the woods of NH, so there isn't much light pollution around, but the moon appeared about twice as large as normal.  I have noticed the same phenomenon on occasion with the sun on a very hot day, or as the sun is setting.  Other times (at sunset) the sun seems "normal size".
Thank you very much for taking the time to answer my question.  I appreciate your willingness to give up your personal time to answer my question!

Answer
Hi Mara,
Yes, anything to do with size change, shape change,
color change like the orange sunsets or deep yellow
moon rises, shimmering, twinkling, color changes
in a bright star....it's all our atmosphere, and not just the moisture in it, it's the air itself.

If we had no atmosphere, one would see none of these;
the stars would not twinkle, and they would stay just as
bright, right down to the horizon; the sun and moon would
appear to be the same as they are straight overhead, right
down to the horizon.  We live at the bottom of a swimming
pool, astronomically speaking.
Of course, without the air, we wouldn't be here either, so its
something of an irritant that we just have to learn to live with.
Hope all this helps.
Clear Skies,
Tom Whiting
Erie, PA

Astronomy

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Tom Whiting

Expertise

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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