How to clean an eyepiece

[JonnyN]

Hi all,

Just got an 8mm BST Explorer/StarGuider EP through the post which I managed to pick up off AstroBuySell secondhand for £35 (dunno if thats a good price or not but £12 better than new so hey ho). I'm really pleased with it, feels really good quality and the guy I bought it from was top. I think its one of the newer ones as well as its branded StarGuider rather than Explorer (or have I got that the wrong way round) and it looks in really good nick but it does have a bit of dust, lint and what look like water marks at each end of the glass. What's the best way to clean it? I was thinking of just using a glasses cleaning cloth but I'm petrified of doing any damage to it.

Also slightly offtopic and I'm really going to show my newbie colours here but the end of the eye piece screws out and I'm wondering for what benefit, is it for minor focus adjustments after you're done using the main focuser or is it meant to increase eye relief by just physically moving the plastic surround further out? I'll obviously be able to find out for myself tonight when I'm home from work but just excited to learn a bit about it before then.

Cheers!

[JonnyN]

Just realised that the actual glass isnt moving when you screw it out so its obviously not focusing anything, ignore that part lol feel stupid now. So I'm guessing just to increase the eye relief?

[DirkSteele]

Buy this (and the cloth)....

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

There are pdf instructions on that page as well. Very simple and straight forward.

Clear skies,

[Moonshane]

hi there

no such thing as a daft question - better to ask and find out than miss out on a good feature. these eyepieces have adjustable tops to allow you to set the position to suit your circumstances - e.g. someone wearing glasses will need it at a different position (lower) than someone not. once you find the right position, set it and leave it.

re cleaning, from your description I'd just use a puffer / blower and do nothing else. I only clean optics when they really need it (or just before selling) and have not cleaned mine for over a year. the odd bit of fluff etc will not affect the view or cause any damage.

if you really want to clean them a lot of people rate the Baader Wonder Fluid and cloth, available from FLO. eyepiece coatings are very hard and difficult to damage unless you drag hard bits across them. make sure they are free of any debris and apply as little pressure as possible but don't overly worry about cleaning them or about damaging them when you do.

when I think of how I used to clean my binoculars I now shudder but there's no obvious damage even though I just used to wipe them with the corner of my shirt!

[JonnyN]

Thanks guys, will give it a go tonight with some other lens cleaning fluid I've got!

[John]

Careful how you do it. Don't flood the lenses with fluid. You need to apply a little fluid to a micro fibre cloth and then apply it gently t the lens surfaces AFTER you have used a puffer brush to blow any debris off the lenses. Personally I'd not use anything other than the Baader fluid and cloth but I've messed up a good eyepiece in the past so my fingers are burned !

[Stargazer_00]

Not to overstress it but dont even attempt to clean it without a puffer. Cleaning an eyepiece with even one flake of dust on it would be like rubbing grit directly on your glass!

You can get puffers cheap from loads of places.

[JonnyN]

Thanks for the warning all, have held of cleaning it as I don't have a puffer or the proper baader liquid so have now got them on order! Just shame the skies are Rubbish, the EP is just sat in the focuser taunting me!

[JonnyN]

Well I managed to get hold of a puffer from one of the guys at work as well as his lens cleaning pen with fine felt one end and soft brush the other (he's big into his photography).

Puffered the hell out of both ends and then warily brushed away any of the more stubborn spots and then polished with the felt end. The EP has come out lovely and spotless and now I can't wait even more to try it out! Sod off snow and clouds!

[Stargazer_00]

Great news