Is my EP cactus?

Sausageman (Mike Boggan) · #1 26-03-2006, 06:00 AM

Had my scope at work last week to show the guys the night sky.
I took out my trusty Tele vue 11mm to look at Saturn and Jupiter and noticed a fingerprint on the lens. Making the viewing blurry.
I took it apart, cleaned it as I would a mirror with Isopropyl alcohol, and put it back together.
No joy, I have clarity around the edge but still a blur in the middle.
Any ideas?
As it has been in its box for 8 weeks with the print on it, has it ruined it?
Is it cactus?

Mike.

asimov (John) · #2 26-03-2006, 08:16 AM

Hmmm. I have heard that leaving a print on a coated lens for too long will eat/etch the coatings permanently. If you've cleaned it already.....I wouldn't like to speculate here, but it sounds like it could be cactus!?

matt · #3 26-03-2006, 10:17 AM

I thought it would take longer than that for oils in finger prints to eat into the coatings?

asimov (John) · #4 26-03-2006, 10:32 AM

In this link, they say to 'promptly' remove the print but no clue as to how long before the print etches the lens.

I reckon its just smeared, & may need more cleaning.

http://www.cybercollege.com/tvp014.htm

matt · #5 26-03-2006, 10:34 AM

I guess it depends on the individual coatings?

John B would know.

Starkler (Geoff) · #6 26-03-2006, 10:41 AM

Maybe you didnt put it back together properly?

Apparently Televue can service their eyepieces and replace individual lens elements although its probably not worth it for a plossl.
I would contact Bintel and see if they are able to help even to just properly clean ,reassemble and assess.

casstony · #7 26-03-2006, 10:55 AM

I've used a relative's eyepieces on which the coatings looked so cloudy as to be almost opaque, though the eyepiece still functioned reasonably well. I'm assuming that the coatings were damaged by eyelash oils, though I can't rule out other causes such as eye makeup.

Tony

asimov (John) · #8 26-03-2006, 10:56 AM

I had the same scenerio with an eyepiece a year ago (showed it to a friend after receiving it brand new & I said "dont touch the glass" & wot happens!? she touches the eye lens with her thumb!!!!) I cleaned it the next day & its as good as gold.

Sausageman (Mike Boggan) · #9 01-04-2006, 10:44 AM

Sorry I haven't answered brfore now.
I have been on night shift and unable to use the computer as my son sleeps next to it.
I will try cleaning it again, but I don't think it will do much good.
I did assemble it wrong at first but re-did it
I think that I will will just have to buy a new one.

Mike

ving (David) · #10 01-04-2006, 11:56 AM

i'd say that if yout EP looks like this then you have serious problems!

janoskiss (Steve H) · #11 01-04-2006, 12:31 PM

Just don't pull the next one apart, Mike. There is no need to. The inside lenses should not get dirty.

But maybe you can save your EP still. Concave lenses go on the outside, convex on the inside. Couple of pics:

http://www.frostydrew.org/observator...pes/plossl.gif
http://www.twcac.org/Graphics/plossl.gif

Sausageman (Mike Boggan) · #12 01-04-2006, 10:58 PM

Ahh.
Thanks Steve.

LOL. What an Idiot I am.

Mike.

Sausageman (Mike Boggan) · #13 01-04-2006, 11:00 PM

Dave,
The link you sent wouldn't load.

Mike

ving (David) · #14 02-04-2006, 12:52 PM

hmm... worked for me

here it is anyhow

Vermin (Tom) · #15 02-04-2006, 01:44 PM

Worked for me too (took a while to load though).