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From: TerryMoselaol.com
Date: Mon, 6 Jun 2005 18:01:28 EDT
Subject: Venus, NLCs

Hi all,

Look out for Venus on 8 June, when it will lie about 5 deg below right of a 
nice young thin crescent Moon, very low in the WNW.

This is the start of the local season for Noctilucent Clouds, or NLCs. 
'Noctilucent' means 'night-shining' and these beautiful high-level clouds are indeed 
visible long after all other lower clouds have ceased to be illuminated as 
the Sun slips lower and lower below your local horizon. The are visible only 
when the Sun is between 6 and 16 degrees below the horizon, and are visible then 
because they lie at an altitude of about 80-85km, and so catch the Sun's light 
even in deep local twilight. 
   They may form around tiny particles of meteoric dust, and they appear as 
lovely silvery-white, sometimes slightly coloured, wispy bands and sheets, low 
down in the Northern part of the sky. They often appear near Capella, which 
lies low down in the North near local midnight at this time of year.
   They may put on their best displays near the time of Solar Minimum, so 
2005 could be a good year!
   You can get lovely photos with exposures of about 1/2 to 3 seconds, 
depending on your film speed and lens aperture, or even try the auto setting on a 
digital camera. The small viewing screen on the latter won't do them justice, so 
keep all images that seem to be correctly exposed & look at them on your PC 
screen later before deciding which ones to keep & print. 
   They are best seen from the N half of Ireland, but have been reported from 
the far South too, although very low down from there.

Clear Skies,

Terry Moseley


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