D-Day Refractor Lens removal & Cleaning

[GordonCopestake]

Is the ST120 a cemented doublet?

[Macavity]

Now there's a thought.

I know my ST102 conforms to the (documented) idea of being a "Fraunhofer Airspaced Doublet". This may be evidenced by the three little "spacers" between the elements. But, as I say, I didn't struggle to separate the two lenses! Here's ONE article (from CN) which describes the cleaning of such a lens:

http://www.cloudynights.com/documents/cleaning2.pdf

Interesting that the GENERAL consensus seems to be that cleaning such a lens is a fairly resonable amateur exercise. Not so with high end achromats or apochromats! Cheaper lenses are likely machine polished and radially symmetric, but you might as well mark the relative position anyway - My ST102 already has such a pencil mark.

Might have mine out again today(!) to clean the OUTER surfaces. Like everything else 'round here, it's covered with MDF dust and also the tube thread tends to shed metal filings (sic!) when (un)screwing. I just bought some "Lithium" Grease, which will hopefully help reduce the latter...

[russ]

I can't seem to split the elements on my ST120, do you know if its possible without breaking anything?

hammer and chisel should do it

[Rob]

Just been out with the scope with awful seeing conditions, the wait to try the Vixen has been killing me!!.. Managed Saturn no worries (same as usual) and star collimation check seems good.

All in all happy man . Job done & saved myself £70!!

[themos]

8) 8) 8) kudos!