Hi Chris,
The problem doesn't occur when bino-viewing from my backyard. It happens when I go to one of our dark sites. 20minutes and the outside of the lens is all fogged up
The AOE 7x50 which are nitrogen purged don't seem to fog up so easily.
So your suggesting I stick with my current binos and not worry about purchasing new ones? Are there dew heaters for binos?
Quote:
Originally Posted by chris lewis
Does the dewing occour internally as well as externally ? Dewing occours when moving from a warm envoironment to a cooler one - usually fairly suddenly. The dewing mainly occours on the outside lens. This will still happen whether they are W.P. / nitrogen purged or not. Binoculars that are W.P will stop internal fogging and long term deterioration from midew / dust spots. My top end W.P. Leicas and Minox's still have dew form on the outside lens esp. when I move from a A.C room to the warm / humid oudoors- it can take 30 mins for the external fogging / dew to go. I sometimes have to acclimatise the binos. first by leaving them outside for 30 mins or so. Both the binos you have are good astro. binoculars. They both have a 7mm exit pupil which is best on very dark skies / and or with 'young' eyes - older eyes ie. 40 + usually cannot dilate to 7 mm which can mean wasted aperture. The other 3 binos you have nominated are aslo good quality binoculars again with 7mm exit pupils - only the 10x50 Pentax has a 5 mm exit pupil. All the binos you have nominated have a relatively narrow FOV. The Celestron 9x63 will let you 'see' more but only incrementally really then your 8x56's. You need to got to a 70 mm aperture bino really to notice the difference. Most can hand hold 10x and 12x really is the maximum for free hand holding. If you do go larger ie. 15x70 you will noticably 'see' more, but will need to tripod them to maximise there abilities. The Celestron 9x63 is a good choice but honestly you will only see marginally more then your existing 8x56's and it will still fog externally.
Chris
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