Dirty eyepieces will hamper all your views through your telescope. Here’s what I discovered about how to clean telescope eyepieces – especially the things you need to avoid.
The main advice: dust and grit is the enemy! And so is mold.
The following will have you getting the most out of your viewing. If you’re interested in extra eyepieces, check out my article about choosing the right telescope eyepieces.
Why this is important? Eyepieces need cleaning more often than objectives since they are handled more and tend to collect fingerprints, eyelash grease, and dust.
The oils in fingerprints and eyelash grease contain acids and this creates smudges and degrades viewing quality through your telescope.
The following is a guide for eyepieces, based on my research. Note: It’s best to check the manufacturer’s directions for cleaning products, especially telescope mirrors or fluorite elements, or if their directions vary from the below (always follow that of the manufacturer).
Should you use an eyepiece cleaning kit?
Yes, an eyepiece cleaning kit is helpful. It makes life easier, as you can quickly put your hands on all the items you need to clean your eyepiece optics.
You can buy one already compiled or put one together yourself. Apart from the lens cleaning liquid, contents may include a soft lint-free microfiber cloth, a soft anti-static brush, Q-Tips (earbuds), or similar, and a case for storing the contents.
Telescope eyepiece cleaning kit examples
The following kits are available at Amazon. Orion has an optics kit you can check out also if you’re interested in a good telescope eyepiece cleaner kit (listed further down).
| Image | Item | Features | Shop* |
|---|---|---|---|
 | Zeiss Lens Cleaning Kit | Air blaster + lens brush | View! |
 | Celestron Lens Cleaning Kit | Lens brush | View! |
 | Altura Photo Professional Kit | Air blower + lens brush | View! |
How do you clean telescope eyepieces – the tools
Scratching the surface of your eyepieces will ruin your views through them permanently. If you happen to get your telescope wet, it’s important to take care in the drying process.
That’s why it’s best to take a few precautions – such as using the right cleaning tools – so you don’t have to worry about harming your eyepieces.
Anti-static brush
An anti-static brush is a good idea as it won’t attract dust or cause dust to collect through static charge like others may, especially during cold conditions.
Blower
As a blower, consider a bulb-type puffer. An ear syringe, which you can get from the pharmacy, will work.
Lint-free cloth
You’ll need a soft, lint-free cloth. Make sure the cloth you’re using isn’t so abrasive that it could scratch your lens surface or remove any anti-reflection coatings.
A microfiber one won’t leave behind lint. Lens tissue is useful if you prefer it. Just know that you want to avoid anything that’s going to deposit lint on your eyepieces.
Q-tips
You can use Q-tips, but make sure they are 100% cotton and not made of polyester or other synthetic materials that create static.
Alcohol
The solution you use to clean the lens needs to be a special type. Use 91% pure isopropyl alcohol, which comprises alcohol and purified water (no minerals). Avoid alcohols with lanolin or other oils that you find in solutions of rubbing alcohols.
10 Steps to cleaning your telescope eyepieces
- Use good lighting in a dust-free environment when cleaning
- Blow dust particles from the surface – a bulb-type puffer is best*
- Use a light touch with a small soft anti-static brush to remove dust or dirt from the lens
- Now examine it for smudges and goop
- Lightly moisten a Q-Tip with the cleaning solution for the lenses. Don’t overdo this. Too much solution may tend to pool and along with the goop collect in the eyepiece itself.
- With the moistened Q-Tip, start in the center and lightly wipe the lens with the Q-Tip in a circular motion until you reach its outside edge
- Mop up excess cleaner with a dry Q-Tip end and repeat the previous and this step
- Use a microfiber cloth or lens tissue to gently polish the surface of the eyepiece to remove any lingering debris
- Wipe down the outside of the eyepiece as well, using either water or alcohol
- Allow everything to dry for at least an hour before putting them away in their cases to store
*If using canned air, use with caution as you want to avoid damaging the special eyepiece coatings from getting the icy cold liquid propellant on the eyepiece
Manufacturer cleaning instructions
What do top brands such as Televue instruct on cleaning eyepieces? Here are the main cleaning points documented by Televue for their Plössl and Panoptic:
- Blow dust particles off using a bulb-type puffer
- Don’t pour the cleaning liquid onto the surface
- Use Windex (or Glass Plus) to clean the lens surface (According to the Televue website: “The anti-reflective coatings on eyepieces and objective lenses are durable enough so that almost no liquid (short of a corrosive) is going to damage them.”)
10 don’ts on cleaning telescope eyepieces
- Don’t use household cleaners as they may have additives that can cause damage to lenses on the eyepiece. Avoid using acetone- and alcohol-based products that contain additives, e.g. rubbing alcohols and nail polish remover, that could damage the protective coatings on lenses
- Don’t blow off dust with your mouth or you risk moisture droplets spotting the lens
- Avoid touching the surface of the lens with your fingers to prevent adding oils and dirt from your skin
- Never pour the cleaning solution directly onto the lens – use a Q-Tip or similar swab
- Avoid using straight tap water when cleaning telescope eyepieces as it can leave minerals deposits – demineralized, distilled, or RO water is best
- Avoid using paper towels or facial tissues that will leave lint when cleaning the lens
- Avoid using a heavy hand when wiping with the cleaning solution – It won’t pick up more gunk and increases the risk of wearing away the coatings
- Definitely do not use a vacuum cleaner to blow the dust from your telescope eyepieces
- Don’t clean the optics if they aren’t dirty. This will lessen the chances of accidentally scratching them
- Don’t store your telescope eyepieces in a moist humid place that’s likely to promote mold growth (which is tricky to get rid of) or where they could get knocked over or damaged by other objects
+ Don’t use general eyepiece cleaning solutions on telescope mirrors or optics containing fluorite or other variations – check with the manufacturer if unsure.
Good tips when cleaning telescope eyepieces
Here are some tips …
storing your eyepiece cleaning kit
Store your eyepiece cleaning kit in a poly bottle that your eyepieces normally come in.
Tip on cleaning your microfiber cloth
You don’t want a microfiber cloth with oil and grease marks remaining from the last clean job. So here’s what you do…
Wash it in warm water with plain and simple soap – one free of sulfates, parabens, heavy perfumes, and dyes. Rinse thoroughly, once again in warm water, and then re-rinse in distilled water or RO water.
Dry it in a lint-free place. You want this so the cloth stays dust- and residue-free for the next cleaning action, so there’s no frustration about it transferring any oil or grease back onto the eyepieces.
Info sources
I like to thank Rich Warp for his input via Cloudy Nights for the above tips | Televue Instructions