White wobbly balls

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suthers

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Dec 9, 2008, 6:39:26 AM12/9/08
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A heartfelt plea to one of the astronomy forums I visit caught my eye
last week. A beginner to amateur astronomy had tried to observe
Jupiter and Venus with a 90mm Celestron refractor and was very
frustrated at the result with both appearing simply as "white wobbly
balls". This was despite previously obtaining good images of the Moon.
She wondered whether she needed to invest in more powerful or more
expensive eyepieces. One responder suggested that possibly her
telescope needed collimating (aligning of the optics).

In fact, as I suggested, the problem was nothing to do with her
equipment. The effects she was suffering were due to turbulence in the
atmosphere, that invisible barrier between us and the universe, and
was a phenomenon known to astronomers as "seeing". Applying more
powerful magnification would simply produce a larger, dancing blob!
Both Venus and Jupiter were low in the sky from her location and so
their light was passing at an angle through a greater depth of
atmosphere. When they are higher in the sky, there will be occasional
nights with good "seeing" when it will be possible to discern that the
image is sharper and clearer with one's present eyepieces. Only then
will it be worth applying a higher power.

Paul
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