What I noticed cleaning eyepieces

[sorrimen]

Hi everyone

I’m very new to telescopes in general but have bought some BST Starguiders. Sadly the two times I’ve gone out they’ve dewed up completely, which I never realised was a problem, but left a fair amount of residue behind. I also accidentally thumb printed one (silly me).

Anyway, I have some baader wonder fluid and started cleaning them. I watched videos but what I noticed was there would always be a residue from the cleaning solution left behind. What fixed it for me was letting dry for 10 seconds or so, then going through meticulously drying it up with cue tips (cotton buds). It felt wrong at first but I kept circling each area until it was clear and that seemed to work a treat, rather than just letting it air dry. I’m sure 99% of you won’t even have this problem, but for whatever reason I’m crap at cleaning things and not leaving streaks (mirrors especially) so if you’re anything like me, try this out.

Also, feel free to share any of your cleaning routines, I’d love to hear them and get more advice! 

[Uplooker]

Having some element of “dirt”, whether that be eyelash grease on the EP will have little if any impact on the views. Best to use a bulb blower to get rid of particles of dirt, prior to any cleaning. Best of all, avoid cleaning unless it is likely to etch the coatings, i.e. bird poop

[bomberbaz]

I clean mine on average once a year or maybe less. As Ian says above a little grime will not have a hugely noticeable difference on your performance, hence my infrequent cleans.

As for mirrors, I have only once cleaned a mirror, the said mirror was something of a dust magnet though.

[Alien 13]

The problem with any solvents is that they can only dissolve grease spots then evaporate leaving a thin film of grease behind, the method you describe moping up the grease loaded solvent before it dries makes sense and far better than the hours of rubbing required after its dried. I am one of the very very few outcasts that just use a lens pen, one swipe and any grease is gone 🙂

Alan

[great_bear]

Unfortunately it *is* important to remove eyepiece dirt because - like cleaning your car - if you avoid it, you can get spots permanently etched onto the surface.

But do be *very* careful when using cotton buds and tissue - it's easy to apply too much pressure and scratch the lens due to a trapped dust particle. I've also known some toilet/kitchen tissues to have particles trapped *within* the manufacturing of the tissue itself!

For genuinely dirty eyepieces, always use a brushless-bulb-blower first, then visually confirm under excellent lighting that the surface is particle free, and check the tissue/bud is also free from contaminants before slightly dampening with isopropyl or wonder-fluid and wiping, and even then use only the lightest of touches to get the job done. 

There are some excellent additional tips on the Televue web site.

HOWEVER - the best technique of course, is not to get them dirty in the first place. ALWAYS keep them capped (at least the top one) when out, and always bring them indoors with both caps securely on - or they'll quickly get covered in condensation, which can lead to mould spots if then re-capped in that state.

Be aware at public events, unskilled observers often fail to see anything due to incorrect eye-placement, and may immediately use their thumb to wipe the eyepiece! It's jaw-dropping when it happens, but they don't know any better. A lot of folks use "junk" eyepieces when allowing randoms to look into the scope for that reason alone.

Anyway, if kept clean through careful use, the only eyepiece maintenance required is normally:

1. First a brushless-bulb-blower to remove dust that's landed on them
2. The very edge of a fold of new, *dry* tissue to merely "poke-away" (NOT wipe!) any stuck particles before blowing off the surface with that bulb-blower 
3. Then a genuine brand-name lens pen from a reputable dealer - but ONLY if (and where!) there are visible surface marks (again, only the lightest-of-touches)
4. A final blower blast, to remove any remaining lens-pen particles

I can't remember the last time mine were bad enough to require any application of fluid... Five years or more?

P.S:

• Avoid using lens brushes on eyepieces in particular. They may appear to work at first, but the dust is often sticky with eyelash-sweat and gets smeared everywhere the next time you use that brush, and the brushes almost impossible to clean after that.
• Fake lens pens have been common in the past, and are a disaster. Sure they seem expensive when purchased from (e.g.) FLO, but you're getting the real thing - I've had a fake one bought elsewhere before, and believe me, its really not worth the risk!

Edited June 9, 2022 by great_bear

[sorrimen]

Oh yes I forgot to mention the use of a bulb blower frequently throughout, quite right! I agree, less cleaning the better. Certainly learned my lesson and eyepieces are staying pocketed from now on.

[bosun21]

I just wanted to check that when you say you let the Baader wonder fluid dry, that you are not putting the fluid directly onto the eye lenses. You should be putting a couple of drops or a quick spray onto your microfiber cloth.Then gently wipe the surface of the lens (after a blow of air to get rid of any loose dust etc). I literally don’t have anything to dry.

[Spile]

A combination of Baader fluid and a unused corner of the matching cloth works for me. I would not trust a qtip

[great_bear]

+1 for that Baader cleaning cloth. Big fan of that for both eyepieces *and* for mirror spots. 
 

When washing (any) optical cleaning cloth, I normally finish up giving them a good hand-rinsing with distilled water. Tap water leaves scratchy limescale powder deposits otherwise. 
 

I also find that the cleaning cloths given away with spectacle cases are usually terrible and go straight in the bin. 

[munirocks]

All of the above is good advice but I will add...

I use a strip torn from plain Kleenex - not just any tissues but real Kleenex - wrapped around a cotton bud, using the cleaning fluid to help the strip stay wrapped. Use the side of the tip, never end-on, with practically no pressure, the way that Italian picture restorers touch a painting. Using the side helps prevent your own sudden twitches  from putting undue pressure on the lens (which is where I would worry about lens pens which are used end-on).

Change the tissue strip often. If the lens is dirty I might go through ten strips. If there is a stubbornly dirty area RESIST the temptation to push "just a little bit harder". Use more swipes -- not more pressure. 

To get rid of sleeks I almost always have to do the final polish using distilled water from a ready source -- my breath.

[sorrimen]

12 hours ago, bosun21 said:

I just wanted to check that when you say you let the Baader wonder fluid dry, that you are not putting the fluid directly onto the eye lenses. You should be putting a couple of drops or a quick spray onto your microfiber cloth.Then gently wipe the surface of the lens (after a blow of air to get rid of any loose dust etc). I literally don’t have anything to dry.

Yes definitely not. Perhaps I’m still using too much on the q tip. Tried the microfiber cloth instead but just couldn’t reach the outer edges. Also, almost bought an eyepiece off you, shame I just missed it!

[sorrimen]

3 hours ago, munirocks said:

All of the above is good advice but I will add...

I use a strip torn from plain Kleenex - not just any tissues but real Kleenex - wrapped around a cotton bud, using the cleaning fluid to help the strip stay wrapped. Use the side of the tip, never end-on, with practically no pressure, the way that Italian picture restorers touch a painting. Using the side helps prevent your own sudden twitches  from putting undue pressure on the lens (which is where I would worry about lens pens which are used end-on).

Change the tissue strip often. If the lens is dirty I might go through ten strips. If there is a stubbornly dirty area RESIST the temptation to push "just a little bit harder". Use more swipes -- not more pressure. 

To get rid of sleeks I almost always have to do the final polish using distilled water from a ready source -- my breath.

I think I was using far too much pressure, but didn’t seem to damage anything I hope. That last tip I was considering but figured it was bad to do after cleaning. Next time I’ll try it.

[Louis D]

7 hours ago, sorrimen said:

I think I was using far too much pressure, but didn’t seem to damage anything I hope. That last tip I was considering but figured it was bad to do after cleaning. Next time I’ll try it.

Just huff upward holding the eyepiece above your mouth, so you're less likely to get saliva on it.

[Don Pensack]

I have had eyepieces for >20 years that I sold that looked brand new.

I clean them by:

1) blow off all debris to avoid scratching.  I have an electric blower (no propellant or oil) that blows just about everything off.

2) I add 1-2 drops of fluid to a Q-Tip, and, while the Q-Tip is wet, make a spiral pass of the entire lens surface, starting in the center, then quickly flip the Q-Tip and repeat with the dry end to mop up the residue.

3) I quickly grab a 2nd Q-tip (cotton only, no additives) and, moving from edge of lens to just past the center of the lens, rotate the eyepiece under the Q-Tip until the whole lens has been brushed twice.

I then flip that Q-Tip to the clean end and repeat the spiral pass.

 

When done, no streaks, no residue, and a clean lens.

 

One way you know the lens is very clean is that the resistance to the movement of the Q-Tip on the lens disappears during the process, as if the lens is teflon coated.

 

[great_bear]

Quality of Q-Tips may be better in USA. Here in the UK “Cotton Buds” (as they are known here) can be quite variable. I used some Sainsbury’s own-brand ones today, and they were shedding fluff all over the lens surface

Didn’t affect cleaning much - I just blew it away as it happened using the bulb-blower. 
 

My Orion 2” Ultrablock filter is proving tricky. One side is perfect but the other side looks like it has a lot of dust, but in close inspection it’s a myriad of tough surface specks that don’t want to go away.  I *think* I’ve made it a bit better, but I’ve stopped before risking it further.

is mould-remover safe to try on an ultrablock @Don Pensack or would that destroy the coatings do you think?

[Don Pensack]

Filters have a lot of coatings and can be easily scratched.

I would go with Lumicon's recommendation to never use anything stronger than isopropyl alcohol.

Pure ethyl alcohol would work too but it is illegal for sale in many places since it can be consumed.

Something strong enough to remove mould, like MEK or a solution of sodium hypochlorite would likely damage the coating.

[sorrimen]

On 10/06/2022 at 20:33, Don Pensack said:

I have had eyepieces for >20 years that I sold that looked brand new.

I clean them by:

1) blow off all debris to avoid scratching.  I have an electric blower (no propellant or oil) that blows just about everything off.

2) I add 1-2 drops of fluid to a Q-Tip, and, while the Q-Tip is wet, make a spiral pass of the entire lens surface, starting in the center, then quickly flip the Q-Tip and repeat with the dry end to mop up the residue.

3) I quickly grab a 2nd Q-tip (cotton only, no additives) and, moving from edge of lens to just past the center of the lens, rotate the eyepiece under the Q-Tip until the whole lens has been brushed twice.

I then flip that Q-Tip to the clean end and repeat the spiral pass.

 

When done, no streaks, no residue, and a clean lens.

 

One way you know the lens is very clean is that the resistance to the movement of the Q-Tip on the lens disappears during the process, as if the lens is teflon coated.

 

This is great, thanks so much! Followed this for my final mucky eyepiece and it worked a treat.