TheSkySearchers

Years ago I found this 102/600 lens for sale and bought it for a project scope, cutting down a 102/1000 tube to make a shorter, faster ‘scope.

When my health went south I packed up all my toys and this week started unpacking things. Looks like I did not do a very good job protecting this one.

Any hope for it, and how would I go about making it “right”? It was nothing exceptional but gave decent views and I hate waste.
Thanks

Are those spots on the inside?

Yes, they are.

Depending on the design there might be a way to pool the lens cell out. Then you can clean the internal lens surface. There are a few members here with experience in taking refractors apart. They may give you pointers if you provide model details

What make is the refractor and is it a doublet?

I am not seeing anything in the image that looks like fungus so likely just condensation

If it is a doublet there should not be to much holding the lens in place.
If you can get it apart you can give the lens a good bath (soak) in distilled water and a bit of dish liquid.
A gentle scrub should clean it up fairly well.

I had a lens set that was so filthy I had to let it soak for almost 4 days before everything came off and it still puts up good views now.

Lady Fraktor wrote: ↑Thu Dec 29, 2022 4:32 am What make is the refractor and is it a doublet?

I am not seeing anything in the image that looks like fungus so likely just condensation

If it is a doublet there should not be to much holding the lens in place.
If you can get it apart you can give the lens a good bath (soak) in distilled water and a bit of dish liquid.
A gentle scrub should clean it up fairly well.

I had a lens set that was so filthy I had to let it soak for almost 4 days before everything came off and it still puts up good views now.

The original manufacturer of the scope was not given, the previous owner needed/wanted the focuser and sold off the lens (if I recall correctly he said the donor scope was made in Japan but I have nothing to verify that statement).

It is a doublet. After my session last night I pulled this scope out and it looks fairly easy to get apart. I’ll give the soak a go and while I have it down go through everything.

Thanks, I’ll let everyone know how it goes in a few days.

Just remember which way the lens fits together, nothing worse than having to take it apart to flip a element
(from experience)

Since you will have it apart, now would be a good time for upgrades.
Blacken lens edges, possibly re-spray the tube inside and/ or outside...

Emphasis on what Gabrielle said. That should be easy to clean as well. I did the same thing with a 60mm scope I made from an old Tasco objective and a cut-down 60mm Celestron tube.

I painted the inside of the tube flat black, and used a Sharpie to blacken the lens edges. For what it is, it really works well. Gabrielle is right too with the lens order, make it easy on yourself!

In this, the crown is to the left and the flint is to the right; picture the scope to the right of the flint; the order in which they came out of the lens cell. Easy peasy!
Best of luck and let us know how it goes!

All the best,

The cleansing went well, soaked most of an eight hour day, carefully rinsed and dried. Painted the inside of the tube flat black (there were shiny silver colored screws from the prior conversion efforts.
My sharpie was pretty well dried up, I’ll have to grab another next time I am out and catch the lens edges.

Good (or better), glass is telling, isn’t it? The little 72 ed II blew this one away. Makes me hesitant to pull out my venerable little ST 80. It also makes me fear for my wallet as I am now hearing a 102 ED calling softly.

Other than the ED glass being better I did get pretty decent views with the exception of mild 4-point diffraction spikes on brighter stars. I cannot remember if they were there before or not.

I will be looking into pinched lenses, reflections off anything inside the tube and my eyesight. I wear glasses but I view without them which may be the culprit?

Anyway thanks for the help, it is greatly appreciated and I’ll keep on keeping on puzzling through this one.

Put your glasses on and look at the star images. If the spikes disappear, you probably have enough astigmatism to require correction with glasses.
If the spikes don't disappear, look for a pinched lens.

Weather has been sporadic and on the somewhat clear nights Luna has been in the way.

The one night I was able to get out just a short while I saw the spikes with and without eyeglasses.

I adjusted the lens’ and hope to get in a session tonight.
Last night was a beauty with very dark, clear skies but I did not get home until very late and did not have time to cool the scope for a good try. ‘Scopes been on the deck for an hour and I plan on getting out by eight. Hoping all goes well with the scope, I’m unreasonably attached to it because it was my first conversion project.
Clear sky’s to all!