rgm40
sage
Reged: 04/15/08
Loc: Western Kentucky
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Increasing contrast using flocking over lens ring
#5310615 - 07/09/12 10:46 PM
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Just curious how many are using flocking material to cover the bottom lens ring to eliminate glare and/or increase contrast at the eyepiece. I was browsing through the forums yesterday and ran upon this thread:
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5052650/page/0/view/collapsed/sb/5/o/all/fpart/3/vc/1
and I asked myself why not do this to all my eyepieces that have a similar designed bottom lens ring? I just purchased a used Ultrascopic 15mm and it has a similar flat bottom lens ring. Have not looked at my other eyepieces yet to compare. Any thoughts?
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Ernest_SPB
sage
Reged: 11/13/10
Loc: St.-Petersburg, Russia
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Re: Increasing contrast using flocking over lens ring
[Re: rgm40]
#5310832 - 07/10/12 02:20 AM
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I do not think this can improve image in any noticeable level. To get ray reflected from the bottom back to eyepiece you need very special conditions and not usual observed objects.
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helpwanted
Post Laureate
Reged: 07/04/07
Loc: Phoenix, AZ
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Re: Increasing contrast using flocking over lens ring
[Re: Ernest_SPB]
#5311080 - 07/10/12 09:17 AM
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I have flocked the inside draw tube on my newt
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ed_turco
Pooh-Bah
Reged: 08/29/09
Loc: Lincoln, RI
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Re: Increasing contrast using flocking over lens ring
[Re: helpwanted]
#5313033 - 07/11/12 05:24 PM
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I am thinking of flocking my eyelashes.
Ed 
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amicus sidera
Carpal Tunnel
Reged: 10/14/11
Loc: East of the Sun, West of the M...
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Re: Increasing contrast using flocking over lens ring
[Re: ed_turco]
#5313075 - 07/11/12 05:41 PM
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Rgm40:
I do not think that such flocking would be of any noticeable benefit. As Ernest said, very unusual conditions would have to exist for it to be useful - perhaps a first-magnitude star just outside of the field or some other uncommon occurrence.
Ed:
One or both eyes? 
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MRNUTTY
Carpal Tunnel
Reged: 11/22/11
Loc: Mendon, MA
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Re: Increasing contrast using flocking over lens ring
[Re: ed_turco]
#5313223 - 07/11/12 07:15 PM
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Quote:
I am thinking of flocking my eyelashes.
I thought you said eyeballs!
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Lew Zealand
scholastic sledgehammer
Reged: 06/28/04
Loc: Pasadena, CA
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Re: Increasing contrast using flocking over lens ring
[Re: MRNUTTY]
#5313625 - 07/12/12 12:29 AM
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The Moon is why you want to blacken everything you possibly can in your visual train. I have a few higher power eyepieces which are very unsatisfying to use on the Moon because they deliver poor contrast thanks to a lot of internal reflections from the parts of our bright satellite outside the field of view. My SCT could use flocking on the inside of the OTA to improve Moon viewing as well and even my 100mm achro could use it for the same reason.
You won't see much of an improvement unless you have cruddy mag 4 skies like here in LA LA land or view the Moon.
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Scanning4Comets
Markus
Reged: 12/26/04
Loc: Hamilton, Ontario, Canada
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Re: Increasing contrast using flocking over lens ring
[Re: Lew Zealand]
#5313714 - 07/12/12 03:08 AM
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I am thinking I may get more contrast by flocking my flocking.
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MitchAlsup
Pooh-Bah
Reged: 08/31/09
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Re: Increasing contrast using flocking over lens ring
[Re: rgm40]
#5316277 - 07/13/12 04:06 PM
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The word is baffle.
You can increase the 'darkness' of an EP by placing baffles in the light path. These baffles need the following parameters. A) they do not vignette light that makes it to the exit pupil. B) the baffles block all stray light that the telescope baffles do no. C) the optimal shape of the baffle is an anular ring with a knife edge cut on the edge. D) The baffles are spaced to prevent illumination of the sides of the EEP tube by stray light.
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