Post by Chicago Astronomer - Astro Joe on Jul 15, 2006 1:23:10 GMT -6
Proper Cleaning of the Eyepiece - Yahoo Group
There are times when in immediate need, I'll yank my t-shirt out from under my shirt and give an eyepiece a wipe. I know it isn't the proper way, but better than peering thru a smudged optic when a line of people are waiting to catch a peek.
I found here at the Telescopes yahoo group a great thread on proper cleaning and care of eyepieces. I post just a segment of several yahoo postings here:
------------------
NEVER USE Q-TIPS!!!!!!!
Q-Tips may feel soft to your skin, but they are hard as rocks to the
soft coatings on lenses. I wouldn't be surprised if you scratched
the coatings when you did your cleaning. the scratches may not be apparent to the eye, but they're there nonetheless. Not only is the stick hard, but the cotton on Q-Tips is processed (like cotton
balls, which should also never be used), causing the edges of each strand to sharpen like tiny blades.
Stick with a roll of surgical (unprocessed) cotton and/or a lens
pen. And BTW, alcohol isn't a great idea either. It can leave a
residue. Lens-cleaning solution is a better choice.
I'm one of the obsessive eyepiece cleaners, both in the field and
after each observing session. I find the smallest amount of eyelash oil or dirt has a dramatic deleterious effect on the image contrast.
I've been carefully following this procedure for many years and the
coatings on my eyepieces are pristine, no scratches or signs of wear.
I always use the following:
1) Blow off any particulates with a large ear bulb syringe (looks
like the bulb blower from a camera store except it is huge and will
give a blast of clean air).
2) Lightly brush off any stubborn particles with a sable artist's
brush.
3) Blow off again to remove anything released by the brush.
4) My first cleaning solution is Kodak lens cleaning solution. It's a
known entity with a long track record of safety on very expensive
coated camera lenses. If the material doesn't come off with the Kodak, I use the Zeiss cleaning solution. You will find that one solution is more effective than the other on certain contaminants. I haven't tried the Baader Optical Wonder cleaning fluid or Purosol yet but they come highly recommended, especially for organic contaminants like tree sap.
www.astro-
physics.com/products/accessories/cleaningproducts/cleaningsystem.htm
4) Machine made q-tips are harsh on coatings. Use
surgical roll cotton, extremely soft with no particulates. Very
inexpensive, available from drug stores or medical supply stores. A
$5 roll has enough cotton to clean a thousand eyepieces. For larger areas like scope objectives or corrector plates I use Opto-Wipes LCW-400's from Opto-Alignment Technologies.
www.optoalignment.com/ow.htm
5) Avoid using too much cleaning solution. You want to prevent any solution wicking around the edge of the eye lens into the innards of the eyepiece. An old photog taught me a trick -- shake the Kodak cleaning solution so it has a head of suds, then hold the bottle _upright_ and dispense a dab of foam onto the cotton. It is the perfect amount of fluid.
6) Roll the cotton against the direction of movement across the
glass, so the leading edge lifts any particles off the glass and
doesn't rub them across the glass surface. Replace the cotton after one complete rotation. Use zero pressure, only the weight of the cotton.
7) I make my own q-tips by twirling a wooden applicator stick (can be purchased at medical supply stores, same place as surgical roll
cotton) while dipping the tip lightly into the surgical roll cotton.
Once you have picked up a dab of cotton with the tip, roll it between your fingers to shape it. With a little practice you can make them look like they came out of a factory and can customize the size to whatever is appropriate for that particular eyepiece. You can make one the size of a fist for corrector plates or objective lenses if you wish. For those tiny eye lenses in short fl orthos, you can snap an applicator stick in half and use the fine point to twirl up a dab of cotton to make a q-tip as small as 1 mm.
8) Final puff of air to remove any lint left by the surgical cotton.
Roland Christen had the following to say about dirt on eyepieces in the Yahoo AstroPhysics users group:
"Eyepieces are mega-mucho far more affected by tiny sleeks and
surface contaminations than telescope mirrors or objective lens
surfaces. The images are highly concentrated and pass through only the tiniest fraction of the eyepiece lens element. A tiny defect on that surface will be very large compared to the image. A dust grain will be a mountain on Mars. Anyone who has seen the effect of a mote of dust on a CCD chip cover plate will know instantly what I'm talking about. That same dust mote or sleek will have zero effect at the front objective."
I can't bring myself to use one of those lens pens, just can't see
rubbing anything across the coatings. All it would take is just one
tiny particle.
===========
I'm going to get me some surgical cotton and no longer use the Q-tips. I would change one thing tho. I wouldn't mold the pulled cotton with my finger tips, unless I was using a gloved hand. No sense in contaminating the cotton with oils from ones hand.
Good advice from the members at the yahoo group...
