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Old March 6th 07, 12:04 AM posted to sci.astro.amateur
W. H. Greer
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Posts: 141
Default Serendipitous Observations

The recent lunar eclipse has come and gone. Like many other
observers, I went out to see what I could see from my location.
Unfortunately, my location on the Earth's surface placed me at a
distinct disadvantage. I was able to see only the last nine minutes
of the umbral phase of the eclipse.

It's very rare that I observe celestial objects as they are rising or
setting; but after doing so I've never regretted it. Under such
circumstances it's possible to see phenomena that are not otherwise
visible.

On this occasion I was treated to two phenomena of interest. First
was the observation of a full Moon, in partial eclipse, distinctly
flattened along its vertical axis by atmospheric refraction. Even
without an eclipse, this was worth observing.

The second phenomenon involved color. Fortunately I had chosen to use
a small, 102mm SCT that was relatively free from chromatic aberration.
(My 80mm, f/5 achromat was left inside!)

A thin, distinct ring of color hugged the lunar limb. The bottom
portion of the ring was red. On both sides of the Moon, as I observed
the ring progressively higher up, I was treated to a familiar sequence
of colors. In order, the colors we red, orange, yellow, green, and
blue.

For me, the highlight of this eclipse were the above mentioned colors,
not artifacts from a telescope, but the result of atmospheric
refraction.

As it turned out, my location on planet Earth wasn't all that bad
after all!
--
Bill
Celestial Journeys
http://cejour.blogspot.com