How to Clean the Optical Lens?

Feb. 21, 2020

Maintaining telescope optical components-cleaning the lens

Cylindrical lens supplier shares with you: To remove dust from the eyepiece, try to inhale between your finger and the lens. Do not blow, otherwise it will leave spit stars.

A quick and easy way to remove dust from the eyepiece is to place a finger on the viewing end of the eye (do not touch the glass!), Draw in air from under the finger, and let the air flow through the lens. This job takes only one second.

If inhalation does not work, the traditional method of cleaning ash-soaked optical components is to gently brush with a camel hair brush. This tool is available at photographic equipment stores, with soft hair and minimal scratch damage to the lens. Brush very lightly. The brush should be stored in its storage box or plastic bag.

Photographic equipment stores also sell compressed gas cans used to blow dust off lenses. Be careful of those who use liquid propellants, it is said that if they are poured or shaken during use, it will spray droplets on the glass surface with residues. Blowing through your mouth (rather than inhaling) can easily leave traces of saliva.

Achromatic Lenses

Achromatic Lenses

For stubborn dust or smudges, there are various lens cleaning solutions. Pure isopropanol or methanol is good, and it is available in drug stores and Wujiaohua stores. Isopropyl alcohol used for medical scrubs diluted by standard is also easy to use and easier to find, but do not use alcohol preparations containing other ingredients to avoid stains. Camera equipment stores sell commercially available lens cleaning fluids such as pure methanol, but you can buy much cheaper at Wujiaohua. There is also a "lens pen" with a soft, retractable cleaning head saturated with solvent.

When cleaning the lens, the liquid should be dipped in a cleaning cloth, not directly on the lens itself. You definitely don't want any liquid to seep in from the edge of the lens, it will bring dissolved greasy matter to the inner surface of the glass, leaving stains in places you can't reach.

You need a soft, grit-free cloth. A clean cotton cloth is fine. Moisten the cloth with cleaning solution, and gently apply the liquid to the lens in a circle without applying pressure. If necessary, dry very gently with a new cloth. Do not drip the liquid directly on the glass, because the liquid can easily penetrate from the edge of the lens, leaving stains on the inner surface.

The grease on the eyelashes and fingerprints, if left on the coating long enough, will permanently discolor it. But this stain is only superficial, and eyepiece manufacturers firmly believe that it will not have a noticeable effect on performance.

If the problem occurs inside the eyepiece, it is best not to take it apart. You will almost certainly skew the lens assembly, and if you try to correct it with too much force, the edges will break. What should be done is to call the manufacturer for professional cleaning.

Unless you are an expert, do not remove the large front lens of a refracting and refracting telescope from its mounting groove. The danger still lies in the skewed and broken glass, or the parts are not assembled into their original shape! With more time and cleaning fluid, achromatic lenses can be cleaned as small.


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