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How to clean telescope eyepiece?

» Telescopes » How to clean telescope eyepiece?

Why and how to clean a telescope eyepiece? The eyepiece of the telescope is the only part of your telescope that is against your eye and is therefore the only part that touches your skin. Because of this, it ends up being the dirtiest part of your telescope and the most likely to contaminate your view. If you look through a telescope through your telescope and see a swirly mass of distortion in the eyepiece, this is likely the cause.



How to clean telescope eyepiece: tips

In this article, I will explain what materials you need to clean eyepieces, the rules for cleaning telescope eyepieces, and how to clean a telescope eyepiece step by step. I will also answer the most common questions. I look forward to your comments with tips on eyepiece cleaning.

Cleaning materials

The telescope eyepiece cleaning is one of the most common ways to keep the telescope optics in a good condition. Indeed, particles of dust or some other particles that are present in the air can settle on the eyepiece when you are observing. This situation can lead to a decrease in the sharpness of the image.

The following items will be needed to clean an eyepiece:

  • Small container of distilled water.
  • Cotton swabs or cleaning tissues.
  • The cleaning solution of isopropyl alcohol (91%) or denatured alcohol – is just enough to dampen the swab.
  • Q-tips or clean cotton balls.
  • Rubbing alcohol (70%) and cotton swabs to remove stubborn marks from the telescope eyepiece.

There is also a telescope cleaning kit. This kit includes a lens cleaning pen, lens cleaning tissue, lens cleaning swabs, and a lens cleaning spray. All are great items to have on hand to keep your eyepieces, finderscope, and telescope optics clean and free of dust, oils, and other contaminants.


Don’ts On Cleaning Telescope Eyepieces

Cleaning is not a difficult task to perform, but you have to be careful to follow the right procedure and use the right cleaning solution and cloth.

First, you have to remove any filters that are in place on the eyepiece. Unscrew the filter or remove it from its holder.

  • Do not leave a telescope eyepiece in cleaning fluid for more than a few minutes.
  • Never use soap and water or other liquid detergents to clean your eyepieces.
  • Don’t use steel wool. It can leave tiny metal particles that will scratch the optical surface of your eyepiece.
  • Do not use wood sticks to try and scratch a telescope eyepiece clean.
  • Do not use a household iron to try and clean a telescope eyepiece.
  • Don’t leave rubber eyecups soaking in any cleaning solution. The rubber will deteriorate.
  • Do not try to clean a telescope eyepiece by sticking it in a microwave oven.
  • Do not try to clean a telescope eyepiece in a dishwasher.
  • Do not try to clean a telescope eyepiece by running it through a clothes dryer.
  • Do not use a stack of old newspapers to try and clean a telescope eyepiece.

Let me repeat, never ever put your eyepiece in water or any other liquid.


Steps: How To Clean Telescope Eyepieces

So, how to clean telescope eyepieces? Telescopes are delicate instruments and should be handled with great care. Carelessness while cleaning the eyepieces can result in damage to the telescope. Here are some tips to help you handle the telescope eyepieces.

Step 1: Handle the telescope eyepieces with care

When cleaning telescope eyepieces, never touch the lenses. Always grip the telescope eyepieces by the body, not the lens.

Step 2: Use Antiseptic Wash

Use an antiseptic wash to clean the telescope eyepieces. This can be done by dipping the telescope eyepiece in the antiseptic wash for a few minutes. Remove the telescope eyepiece from the antiseptic wash and wipe it dry with a clean and soft cloth.

Step 3: Use A Cleaning Brush

A few strands of horsehair or a camel hair brush can be used to clean the telescope eyepiece. Use the brush while cleaning the telescope eyepieces to clean the dirt and dust particles stuck to the lens of the telescope.


Step 4: Use Lens Cleaning Fluid

A few drops of lens cleaning fluid can also be used to clean the telescope eyepiece. Some lens cleaning fluids react with the lens of the telescope eyepiece and can harm the lens. Make sure you use the right kind of lens cleaning fluid for the telescope eyepiece.

Step 5: Use A Telescope Eyepiece Cleaning Swab

A special kind of swab, known as a telescope eyepiece cleaning swab, can be used to clean the telescope eyepiece. These swabs are made to clean the telescope eyepieces and are very convenient to use.

Step 6: Use A Microfiber Cloth

A microfiber cloth can be used to clean the telescope eyepiece. Use the microfiber cloth to wipe the lenses of the telescope eyepiece.

Step 7: Clean The Telescope Eyepieces Before Use

Before using the telescope eyepiece, clean it carefully. Cleaning the telescope eyepiece before use can help avoid contamination of the telescope.

Step 8: Clean The Telescope Eyepiece After Use

After using the telescope eyepiece, clean it again. This will help avoid contamination of the telescope.


Cleaning refractor telescope lens

Below I will tell you how to clean a refractor telescope lens:

  • If you use a lens brush to clean the lens, make sure it is a soft one and not a stiff brush. A stiff brush will scratch the lens. If you don’t have a lens brush, use a soft camel hairbrush. This can be found in most art supply stores.
  • Before you clean the lens, it is a good idea to remove the lens from the telescope. You don’t want to accidentally drop or bump the lens or the telescope.
  • Remove the lens from the telescope. Use a lens brush to clean the outside of the lens. Be careful to not touch the lens with your fingers. The oils on your hands will cause spots to appear on the lens. If that happens, you need to clean the lens again.
  • When you finish cleaning the lens, check it for spots. If you get spots on the lens, you will have to clean the lens again.
  • You can also clean the lens with a special lens cleaning fluid. This can be found in most camera stores. Follow the directions on the bottle.
  • You can also clean the lens with pure isopropyl alcohol. This is the same alcohol you use for rubbing on prescriptions. It may take several applications to get the lens clean.


Cleaning of catadioptric telescopes

The eyepieces of catadioptric telescopes are more difficult to clean than the eyepiece of a refractor. The objective lens of a catadioptric telescope collects less dust than the eyepiece of a refractor since it is larger. The eyepiece of a refractor collects a lot of dust because it is smaller and the observer is closer to it. In order to clean the eyepiece of a catadioptric telescope, you should use a lens brush and a blower. If you have no blower, you can use a vacuum cleaner.

  • The first thing to do is to check the eyepieces and clean them thoroughly.
  • Once the eyepieces are clean, you can check the mirror. If you can see your image in the mirror, then there is no problem, but if you can only see the back of your head looking at the mirror, then it is possible that the mirror has been shattered by a speck of dust.
  • If you do find this problem, then you can ignore it, as the scattering will be very slight, but if you do want to clean it, then I suggest that you work with a dark cloth or dark paper to cover the mirror.
  • Then using a cotton bud, or a very soft brush, very gently rub the mirror from the center outwards, being careful not to touch the front or back of the mirror, and do not use any polish or cleaning fluid.
  • This should be the first step in your catadioptric cleaning regime.

How do I know I need to clean the eyepiece in my telescope?

If the view through the eyepiece is not as sharp as when you first acquired the telescope, or if the star images are not as bright as they once were, then it is likely time to clean the eyepiece.

A typical 1¼” eyepiece contains several elements which, over time, will become dirty and/or encrusted with tiny particles of dust. These particles appear as small, dark patches that obscure the image of the star, or they may appear as small, dark lines that run through the image of the star.


There are several clues that can indicate the eyepiece needs cleaning. The first is your view through the telescope. If you look in the eyepiece and see hair or dust motes, then the first thing your eye will do is blink. This is a natural reaction and is actually trying to remove the offending particle from your eye. This will cause you to lose sight of the object you are looking at.

Another clue that your eyepiece is dirty is if you have to constantly press the eyecup of your eyepiece against your eye. This is due to your eye trying to get a better view of the object by pressing the eyecup against your eye. If you are experiencing either one of these, it is time to clean your eyepiece.


I often hear questions about eyepiece cleaning: how to do it properly and is it worth it? Here I summarize the most popular ones.

What eyepieces do I need for a telescope?

As a beginner, you may be wondering which eyepieces you need for your telescope. The answer depends on what type of telescope you have. Telescopes come in different eyepiece sizes. The most common eyepiece sizes are 1.25″ and 2″. If you have a refractor telescope, you will have a 1.25″ eyepiece, while if you have a reflector telescope you will have a 2″ eyepiece.

Is 10mm or 25mm better for a telescope?

10mm will give you a wider field of view but you can’t see as much of the sky, whereas the 25mm is more powerful but with a narrower field of view.

How-do I-know-I-need to-clean-the-eyepiece-in-my-telescope

What is a Nagler eyepiece?

A Nagler eyepiece is one of the best eyepieces for astronomy. They are made by TeleVue, a company that has been around for many years and has a stellar reputation for making the best telescope eyepieces out there. The Nagler eyepiece is a top choice because of its field of view, which is very large and makes you feel like you’re observing the object you’re looking at in a very wide field of view.


Accumulated dust can reduce the contrast of images viewed through the telescope, degrade image quality, and cause shadows in the image. Dust can be removed by using the telescope dust cover, a soft lens cleaning cloth, or an industrial vacuum cleaner. If you have a lens cleaning kit, use it. Lens cleaning kits are inexpensive and work well.

What tips do you have for cleaning the eyepiece? Tell me about it in the comments, I’m interested in your opinion.

About Michael Oliver Barlow

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