small finger print on eyepiece lens

[firstscope]

is it all over for it or will everything be ok ?

[Naemeth]

Certainly not, to clean it off:

http://www.firstlightoptics.com/misc/baader-optical-wonder-fluid.html

[DirkSteele]

+1 for the Wonder Fluid. I have had worse than a finger print on the lens before at a star party where multiple people were looking through my scope, and wonder fluid brought the affected Televue Delos back to its best. Just make sure to remove any particulate matter from the lens first using a non aerosol based blower (something like this http://www.fotosense.co.uk/giottos-aa1900-super-rocket-air-blower.html) as any particles could scratch the lens, and then follow the cleaning instructions that come with it.

[firstscope]

cheers guys i really need to start been more careful

[Mark in Macc]

If it's only a small smudge, I would leave it. It probably won't make any difference.

[ronin]

Clean it.

Main point is that the top of an eyepiece may have grease close by, there are various threaded sextion at the top, so if you use a fluid don't flood it as that may dissolve some and move it, so meaning more cleaning.

[firstscope]

just a quick update if anybody is interested it seems i have also scratched the lens

its an eyepiece i paid 100 quid for so am gutted but i shall leave it alone now and see how it performs when we next get clear skies

[Moonshane]

highly unlikely you have scratched the coatings as they are pretty hard. often when you clean off an eyepiece the fluid used (I generally use 100% isopropyl alcohol) will leave a streak or two which does look like the coatings have failed. assuming there's nothing abrasive on the lens, normally breathing on the eyepiece and then before the mist disappears polishing very lightly with the supplied cloth (or a decent quality optical cloth) will restore the coatings to their former glory.

[m.tweedy]

here is information from the guru (Televeue)

http://www.televue.com/engine/TV3b_page.asp?id=103

[firstscope]

cheers Shane and michael

[Moonshane]

the main things are don't clean unless you feel you have to, if you have to go easy and if you think you have damaged your coatings (on the eyepiece - it's easier on the mirrors) then you probably haven't so don't panic.

[Mark in Macc]

I use a Lenspen mini to finish when I need to clean. Leaves a perfect finish, but just be careful whatever you do. Make sure there are no bits on the lens before you try to clean.

[E621Keith]

Sorry to hear you may have scratch the lens. That the main reason why we don't clean optics unless it absolutely necessary.

You can check whether it's a real scratch or just a mark left by cleaning by cleaning it again.

The cleaning procedure is as followed:

1. use a air blower to blow off as much surface dust as possible

e.g. http://www.amazon.co.uk/Giottos-GTAA1900-Rocket-Air-Blower/dp/B00017LSPI/ref=sr_1_1?ie=UTF8&qid=1371747123&sr=8-1&keywords=giottos+blower

2. Wet a new lens sheet of len tissue using Baader Fluid. Don't use mircofibre cloth or cheap tissue, they may have grit trapped in it that could have cause the original scratch.

I recommend Pec-pad for lens tissue. It's thick and can absorb quite a lot of cleaning fluid, so it will stay moist for longer

http://www.amazon.co.uk/PEC-PAD-Photowipes-Photographic-Emulsion-Sheets/dp/B0001M6K24/ref=sr_1_1?ie=UTF8&qid=1371747338&sr=8-1&keywords=pec+pad

3. Gently wipe the lens tissue across the mark in a straight line. Make sure the tissue is moist.

If the mark stays, it's probably a scratch. If it moves or disappeared, it probably a streak or dust.

As John mentioned, most lens cleaning fluid leaves streak after cleaning, including the Baader. The only ones I've use that leave no streak is Eclipse by Photographic Solutions and a Lens fluid made by Horiuchi Colour Lab.

Eclipse is aggressive and it dissolved the coating in one of my Celestron X-cel once. After that I use Baader for general cleaning, and only use Eclipse for critical areas such as eyepiece field lens.