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Re: (meteorobs) LM Star Count vs Milky Way Perception
I have no experience with visual observation yet (will try to learn
as many IMO LM area as I could in Spet.), so I would start with my
experience with CCD observations.
I agree with GWG and Lew about seeing (stableness of atmosphere?)
explaination, as well as with Sue about eyesight. My site usually
has good seeing under bad transparency, and bad seeing under good
transparency, which is also true for some other (maybe most??) sites.
Good seeing is important to detect faint object, especially by direct
'looking'. Detection of extended sources could be more 'detector'
dependent, so different people may have different abilities on
extended source detection under same weather condition and under
same point-source detection abilities. The factors of influence
could be the angular resolution, sensitivity, 'exposure time', f.o.v.
of the 'detector' (eye), as well as the sky background and how extend
the source is. Another small effect could be the color effect of
both the source and the detector, and everyone may have different
color response when observe.
I did try some IMO LM field one night under quite good transparency,
with clear Milky Way, but only got LM about 5.0-5.5, but I felt that
it 'should be' better than that. :) I'll have more certain experience
later.
What I think is also important relating (or similar) to this question,
is the detection of moving objects (which might be asteroids for CCD
observation, and meteors for visual). I felt that my eye is not good
for point source (only give LM=5.0 to 5.5 under very good weather??),
but might be very sensitive to moving objects, so it might be given
more meteor detections (of course I mean the real ones) than average
- I'll try to make a comparison when I have some chance to observe
with any of you experienced observer later...
Jin
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Jin Zhu | Tel.: +86-10-62759888 (O)
Beijing Astronomical Observatory | +86-10-68392030 (H)
Chinese Academy of Sciences | +86-314-5053035 (Schmidt dome)
P. R. China | Fax : +86-10-62759888
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P.S.: resent from jinzhu@sun.ihep.ac.cn. My previous sending from
zj@bac.pkudot edu.cn is returned because of local power down problem.