Telescope Reviews: GOTO 102MM F14.7 F=1500 INFO/INPUT NEEDED

Got this old GOTO Tokyo 102mm f=1500 (f14.7) refractor OTA with finder scope yesterday, I am looking for more information and suggestions.

Condition of the glass is excellent. That's fortunate because the tube looks like it has gone through a war. Uncoated doublet group is mounted in a cell, then that cell is threaded into a collimatable cell which is attached to the tube. All I have done is clean the front and rear exposed surfaces and the glass has turned out to be very clear. I suppose not having any coatings to decay helps. I probably won't take the elements out of the cell as I have about 95% transparency as it sits and I don't plan on keeping the scope (already have a 4" f15 Antares). I will let the next owner have the fun of pulling the elements out and cleaning them.

The tube is metal and in terrible shape but worthy of restoration. Looks much better in my photo than it is, it is truly ugly. There are more than a few dents and the paint is horribly scraped. It would take removing the current (enamel?) finish, fixing the numerous dents, then repainting or powdercoating. Same for the dew shield. The focuser actually looks OK, the cell carrier has some paint loss, the cell itself (unscrews from the cell carrier) shows some anodizing decay. Tube has 5 internal baffles.

Eyepiece is a screw-in affair, unmarked as to power or focal length, with very decayed coating on the eyepiece lens and a missing eyecup. The rest of the eyepiece glass is very good, very clear, no other coating issues I can see, and with a very well defined field stop. I will try to figure out the focal length and AOV of the EP when I test the scope (maybe tonight on Saturn).

This scope is big and heavy. 65.5" long with the focuser all the way in and the EP installed, and 24lbs. Tube diameter is approx 4.125", dew shield is about 5.75" diameter.

Has what appears to be the original finder scope and brackets, finder scope is marked GOTO Tokyo, but no specifications. Front element is 30mm and overall length of tube is 16" with the optical path about 14" so this must be a pretty powerful finder scope. No crosshairs in the finder scope, nor does there seem to be any provision for any. Eyepiece of the finder scope has diopter control, much like a binocular, appears to be missing a screw-on eyecup.

Focuser is a very nice rack and pinion, with an excellent vernier scale on the side. It's a bit tight, probably due to old lube. The eyepiece screws into the focuser, along with what looks to be various adapter rings, all of which appear to be original.

I tried to do a Google search on GOTO but of course most of what I get is referencing modern GoTo computer controlled telescopes. I did see a few mentions of smaller GOTO scopes (50mm and 60mm mostly) but I haven't been able to find anything about a 102mm, nor any recorded sales. Can anyone point me to some specific info on the web about this scope? Maybe a scan of a brochure page? As I won't be keeping this scope I will be selling/trading it off but I want to play with it a bit first and also need to know some precedent as to value. Any known sales of this scope in any itteration? Any idea as to the power of the finder scope? Any idea what the "E." stands for that is before the "D=102mm" on the ID ring?

Thanks in advance.

Tom Duncan

Edited by oddog (03/12/11 01:13 AM)