ZIL Posted 3 May , 2022 Share Posted 3 May , 2022 I have Ross telescope but the field of view..ie the size of image through the eyepiece is very small and round.Does anyone have knowledge of these or any source for repair etc. Regards Zil Link to comment Share on other sites More sharing options...
Chasemuseum Posted 3 May , 2022 Share Posted 3 May , 2022 Ross was a major maker of many types of optical instruments. The simple multiple tube draw telescopes were intended to be dismantled and cleaned in the field by a competent artificer. These are easy to dismantle and clean, the problem is dealing with damage to the tubes (dents) and damage to the threads. The threads are a very fine pitch and easily cross threaded by rough hands. They need to be lubricated when being assembled with a quality light machine oil. You can use WD40 or similar to loosen the thread for disassembly but must clean this off with solvent and use light oil when reassembling. Artillery sighting telescopes and more complex instruments were only ever intended to be dismantled by instrument technicians. These need to be serviced by specialists. I used to own a WW2 high-mount SMLE No1 Mk III sniper rifle with the 1918 pattern scope. The lenses are compound lenses with the lenses glued together with a soft organic compound (egg white). This had been contaminated with mould and the lenses were obscured by a spider pattern of mould. I sent it off to a so called expert to be serviced. It came back with a lens chipped and the tube partially crushed and no longer round. It was usable which it had not been before but I was very unhappy with the damage. Finding a competent technician is always the hard part. Link to comment Share on other sites More sharing options...
ZIL Posted 4 May , 2022 Author Share Posted 4 May , 2022 Thank you…very sound advice…I am looking for a specialist as mine is a sighting scope as against draw. much appreciated Zil Link to comment Share on other sites More sharing options...
MikB Posted 4 May , 2022 Share Posted 4 May , 2022 This outfit may be able to help you:- https://www.opticalrepairs.com/binoculars_telescopes_repair_servicing.html I've not used them, but they appear to have dealt with a broad range of complex optics. Link to comment Share on other sites More sharing options...
ZIL Posted 4 May , 2022 Author Share Posted 4 May , 2022 Thanks MikB, Iv’e sent them a detailed email…I’ll see what develops. Regards Zil. Link to comment Share on other sites More sharing options...
Grovetown Posted 6 May , 2022 Share Posted 6 May , 2022 On 04/05/2022 at 13:59, ZIL said: Iv’e sent them a detailed email…I’ll see what develops. Regards Zil. The guy has a superb reputation in optics, so you're in good hands if it's something he can do. As his website states, his son (with the same name) had a similar business in London, but it was beset by problems and I believe it has closed. You've got the guru. Cheers, GT. Link to comment Share on other sites More sharing options...
awjdthumper Posted 6 May , 2022 Share Posted 6 May , 2022 On 03/05/2022 at 10:14, ZIL said: I have Ross telescope but the field of view..ie the size of image through the eyepiece is very small and round.Does anyone have knowledge of these or any source for repair etc. Regards Zil Any chance of some pics so that we can see exactly what you've got? From what you have said, it is not clear whether this is an artillery gun sight or a rifle telescopic sight. If the former then I'm not sure whether it would be worth doing much to it. I've got quite a few panoramic sighting telescopes (dial sights) that I've taken apart and cleaned the optics for but I'm not sure I added much value to them, although I enjoyed doing the work! Link to comment Share on other sites More sharing options...
ZIL Posted 7 May , 2022 Author Share Posted 7 May , 2022 Thanks to both…I’ll attach a couple of photos..bear with me!! Zil Link to comment Share on other sites More sharing options...
ZIL Posted 7 May , 2022 Author Share Posted 7 May , 2022 Photos attachedZil Link to comment Share on other sites More sharing options...
awjdthumper Posted 8 May , 2022 Share Posted 8 May , 2022 Many thanks for posting the pictures. I'm not an expert on these types of telescope but this might be more of a naval signal reading telescope rather than being an artillery gun sight telescope. It is obviously a variable power / zoom telescope with the large knurled section used to change the magnification. I think the biggest problem you have is that someone has added a different, much more modern, eyepiece to it which has probably screwed up the way it works and, in particular, screwed up the field of view. Rather than overhauling the telescope, this may be a case of trying to find the correct eyepiece to make it work properly. Link to comment Share on other sites More sharing options...
awjdthumper Posted 8 May , 2022 Share Posted 8 May , 2022 Looking at the telescope again, I'm curious to know what (the aluminium bit) has been fitted to the end of the end of the telescope - I assumed it contained a lens? I would be tempted to try and remove it to see whether the original eyepiece is still there in working order? Link to comment Share on other sites More sharing options...
ZIL Posted 8 May , 2022 Author Share Posted 8 May , 2022 Thank you….I agree with your comments..the aluminium piece was made by a firm in Dresden that made cameras.There is no lens in it but it does screw in correctly to the eye piece.I feel it is a camera lens extension tube used purely as an end eyepiece as against the rubber one that was fitted to this type of scope. I await a reply to my email and will update as and when. Regards Zil Link to comment Share on other sites More sharing options...
awjdthumper Posted 8 May , 2022 Share Posted 8 May , 2022 I would recommend taking off the camera adaptor tube and then seeing what the telescope does. In optical terms, it's possible the exit pupil is inside the tube and the narrower FOV you were seeing is simply due to you not being able to get your eye close enough to the eyepiece. Link to comment Share on other sites More sharing options...
ZIL Posted 8 May , 2022 Author Share Posted 8 May , 2022 Thank you..I’ve tried what you suggest..same result. It’s not that there is no image..there is but a very small field of view.It can be brought into focus but if as you say a different eyepiece has been used..it’s for very specific and precise target selection .There are also no cross hairs or pointers.I have read that this is a feature of some Ross scopes ..there is also no tube illuminator . Regards Zil Link to comment Share on other sites More sharing options...
awjdthumper Posted 8 May , 2022 Share Posted 8 May , 2022 Does the zoom control not work? If it does then this should change the field of view. As said, this is probably a signal telescope rather than a gun sight telescope - hence no cross-hairs! Link to comment Share on other sites More sharing options...
ZIL Posted 8 May , 2022 Author Share Posted 8 May , 2022 Thanks again..yes the zoom does work but the field of view remains the same. . Regards Zil Link to comment Share on other sites More sharing options...
ZIL Posted 9 May , 2022 Author Share Posted 9 May , 2022 To update ,I have spoken to the guru recommended by Grovetown.There is no doubt that what he doesn’t know is not worth knowing.He agrees that the eyepiece has been changed but to get the correct one is very unlikely.Spares for such instruments are extremely rare.The decision is to leave as is.It is usable but with a narrow field of view. Once again my thanks for all the input..the Forum never fails.Regards Zil Link to comment Share on other sites More sharing options...
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