8 replies to this topic

[coffee_lover]

I have read a variety of ideas some have used in cleaning their objective lens in their vintage Unitron refracting objective lens but some ideas I wonder if they may be doing more damage long term.

There is an article on the Antique Telescope Society "A Professional Method for Cleaning Optics" by Robert Ariail which provides a technique using U.S.P. Collodion. This chemical seems to not cause damage but U.S.P. Collodion could be harmful to people not trained in its use so proper precautions and training would be needed. It seems a product called Final Contact might be a better alternative as it should be safer to use. Are these chemicals only for optical mirrors or are they also for cleaning optical glass too?

I also see there is an archived posting on cloudy nights with the subject "Cleaning Glass to true professional quality".

The Objective lens on the Unitron Model 145 3" Refracting telescope from 1954 I own has "mildew/mold" within the air gap. In addition other eye pieces could use some cleaning as well. I want to reach out to members to learn what would be a safe and proper method to take apart the objective lens and clean it and avoid causing any damage. Are there places that professionally can perform these services and who are some in the US?

Thank you.

[CarolinaBanker]

I’d ask Harry Siebert at Siebert Optics or Suddarth Optical Repair.

[coffee_lover]

Thank you.

[starman876]

Cleaning lenses. Not for the faint of heart.   There have been a lot of articles on CN on how to clean lenses.    They have been very good articles.   Maybe someone else can provide the links.

[jragsdale]

Depends on the lens and what's wrong with it, but I will use tap water and soap (sap, grease, oil), ROR fluid (fingerprints), isopropyl alcohol (haze streaks), hydrogen peroxide (mold, fungus), distilled water (final rinse after soap or HP), acetone. (stubborn spots on final cleaned lens). Remove dirt with air or water before any touching the glass. Lots of articles explain the details.

[Kasmos]

It's not that big of deal for the experienced. If you're unsure about cleaning it, don't do it. Especially since you are selling it and could screw up and the prospective buyer will likely be an experience user that will know how to do it, and probably be happier if you didn't touch it so they could do it themselves.

[coffee_lover]

Thank you for your feedback on this.

[k5apl]

Some things to consider:

Be sure if you use Kleenex type tissues that they don't have lotion added.

I have found full strength Acetone leaves a film. I always do a final rinse/go over with

distilled water.

Some brands of pure cotten balls seem to be more absorbant.

I use distilled water when I make up a cleaning solution...and a drop of Dawn, and a

drop of denatured alcohol to attack mildew.

Mark the edges of the lenses for proper spacer location and original line-up. I Use a

pencil cause ink tends to wash away.

I use straight motions; not circular in applying and drying.

I use a Spanner Wrench from Amazon- much better than my home made attempts

Be patient, work slowly, have fun.

Wes

[JohnH]

I have a pretty old Wolenak telescope that I bought a few years ago in pieces but it needs a very deep cleaning.

It has a filter wheel, protective filter a meniscus but at least the internals being sealed away are all very clean from what I can see just the exposed surfaces. I need to do those clean off any grit that fell on them when it was in my workshop with woodworking tools and Airborne braces and then I'll get working on it again