unknown make vintage 3 inch scope

[DaveL59]

Thanks Jeremy, yeah had to try, at least it's not a big financial hit, so far. Tempted to get some glass cement/glue and stick the spall back in place and see how bad that makes it 

Am wondering if I can fettle a 70mm objective cell into the end as Astroboot may have something. Can always shorten the tube if a 900mm FL lens doesn't quite give enough in-focus. I wonder if the 80mm scopes the lens is slightly more than 80mm as that'll make getting a modern drop-in replacement somewhat harder. A custom made lens looks like it'd be over £100 to get so that's not an option I think. Not like it has sentimental value to me after all but would be nice to find a way to make it usable if I can do it for a reasonable cost.

[JeremyS]

2 minutes ago, DaveL59 said:

Thanks Jeremy, yeah had to try, at least it's not a big financial hit, so far. Tempted to get some glass cement/glue and stick the spall back in place and see how bad that makes it 

Am wondering if I can fettle a 70mm objective cell into the end as Astroboot may have something. Can always shorten the tube if a 900mm FL lens doesn't quite give enough in-focus. I wonder if the 80mm scopes the lens is slightly more than 80mm as that'll make getting a modern drop-in replacement somewhat harder. A custom made lens looks like it'd be over £100 to get so that's not an option I think. Not like it has sentimental value to me after all but would be nice to find a way to make it usable if I can do it for a reasonable cost.

When you get the lens cell out, it will be interesting to see if it has the maker's name or id on it, Dave. A bit academic now, nevertheless interesting to know.

[DaveL59]

only thing was a C in black pen that I noticed, no other markings tho I've not had the focuser end apart as yet. I'm curious too, it's a well made scope so I'm not giving up on it yet. I expect it was a custom ground lens for that too which makes me feel real bad but what can you do. Probably it tilted slightly when I'd loosened things earlier and that little pressure applied on the edge was all it needed. Might ping astroboot and see what outer diameter the Bresser 70mm cell they list is, tho that's 700mm FL so a big chunk to take off this OTA.

[JeremyS]

 

6 minutes ago, DaveL59 said:

only thing was a C in black pen that I noticed, no other markings tho I've not had the focuser end apart as yet. I'm curious too, it's a well made scope so I'm not giving up on it yet. I expect it was a custom ground lens for that too which makes me feel real bad but what can you do. Probably it tilted slightly when I'd loosened things earlier and that little pressure applied on the edge was all it needed. Might ping astroboot and see what outer diameter the Bresser 70mm cell they list is, tho that's 700mm FL so a big chunk to take off this OTA.

Might be worth asking Ian Poyser if he has any suitable lenses: http://irpoyser.co.uk

 

[DaveL59]

17 minutes ago, JeremyS said:

 

Might be worth asking Ian Poyser if he has any suitable lenses: http://irpoyser.co.uk

 

thanks Jeremy, have sent off a mail and will see what he comes back with. There's options I believe, just a case of what it'll cost and so forth. At least it only cost me £20 and some fuel so far  

[DaveL59]

figured I can't do any more harm, so off with the focuser just to see what's what.

one screw and the focuser lock thumbscrew and out it slid.

Removing the eyepiece securing screw I could undo the holder and as expected it's threaded so likely acts as fin focus. Some white gloop on the threads, probably to effect a smooth but draggy motion to reduce slop and drift. I notice too the eyepiece screw is plastic with a brass outer, nice touch as it hasn't marked the eyepiece barrel at all.

View down the tube shows black thin card between the baffles, the screw that's visible secures the finder base so can be improved for sure tho it likely doesn't impinge at all by this point in the optical path.

So plenty of scope to freshen up if I can find a suitable objective, I'd say the previous owner has had this apart in the past, given the later finder and possibly the black card inserted to darken the tube. Might even have built it himself for all I know. For sure one that would be nice to restore so still kicking myself about that lens. Oh well, still hope, maybe  

[Peter Drew]

@ DaveL59.  I have a 80mm F16 objective in a cell that you will be welcome to have if you think it would suit your purpose.  It's from one of the generic refractors of that period.    🙂

[DaveL59]

13 minutes ago, Peter Drew said:

@ DaveL59.  I have a 80mm F16 objective in a cell that you will be welcome to have if you think it would suit your purpose.  It's from one of the generic refractors of that period.    🙂

oh wow, I'd be very grateful for that Peter, thanks very much. Will PM you to sort something.

 

[DaveL59]

Decided to take a look and see how bad the lens damage is, daytime of course target a tree about 300M away

surprisingly not so bad at all!

Tried the 0.965 MA40 and that gives a narrower FoV and a 20mm held roughly on the end of the focus tube even tighter still. I think tho that the MA40 is kinda barlowed as it has a lens in the barrel as well but even so it might just be usable still  

edit - the spall was at the bottom of the objective in the test view

Edited July 16, 2020 by DaveL59

[Alan White]

I feel your pain.
It was obvious you would weaken and buy it at the initial posting.
How your luck has gone with the lens feels all too familiar to me on other projects in the past.
Good luck with however you decide to take this project.

[Alan White]

Oh and based on this run of luck, give the Lottery a miss this week 😉

[DaveL59]

thanks Alan, yeah am a sucker for vintage and giving it a new life and I do like the way it looks and is built. There's hope though from the quick daytime view I did earlier, and of course Peter may well be able to supply an 80mm lens that may well suit.

Just heard back from IRPoyser who unfortunately doesn't have anything in that size but has suggested others who may be able. One way or another I expect this one will be enjoying some starlight at some point in the future, I'm not giving up just yet  

[Roy Challen]

I've been following this thread with interest, bad luck about the lens, Dave. If want to keep the 0.965 setup, I have 3 eyepieces you can have. They came with my Prinz 660, but I don't use them. Either way, I hope you carry on with this old scope.

[DaveL59]

thanks Roy, I hope to resurrect the scope if at all possible.

I'm thinking that a 0.965 to 1.25 adaptor may be the better solution longer term for flexibility, that way I can use my regular diagonal and eyepieces rather than have to contort to crazy angled with a straight through setup as it currently is. Only thing will be to stop the fine focuser from rotating somehow. I'm looking out for a 0.965 diagonal though, at which point a set of the smaller eyepieces may well be a good idea so I can still use the 1.25 stuff on the TAL at the same time. On those lines, I'd gladly relieve you of them if you're sure you won't want them again  

[markse68]

Dang that’s a real bummer Dave  Have you had the objective out since the damage? Is it a doublet? Such a shame

No consolation I know but that Edmund Deluxe red finder I bought as an ebay bargain went in the bin the other day  The brass ep sliding focuser bit was corroded solid in the thick aluminium tube. I tried soaking in vinegar overnight and hot air gun but with nothing to get a decent purchase on all i managed was to shift in in a bit further 🤦‍♂️ Anyway the scientific application of targeted force (hammer and drift) resulted in the crosshairs glass shattering inside and at that point it was a waste of time going further. Shame as it was an unusual and nice thing but very heavy for a finder tbh...

Good to hear you’re not giving up on it and look forward to it’s resurrection

 

 

[DaveL59]

Am starting to think ahead on this one now, in terms of what work to do in restoring it if (when) I can sort the lens faux pas.

The finder cleaned up OK in terms of lenses and reticule, tho not as good as the TAL ones I have and paint is tatty. But the grey/white just doesn't fit in well with the brass and black leather finish. Perhaps I could respray the finder mount with hammerite gold and the finder in black? Too much bling bling maybe? 😉

But then the grey bits on the finder itself would be more of a challenge to strip off and paint. I guess I could change the finder shoe and use an RDF instead to a right-angle finder would likely be a better option. Or try find a brass finder...  

Was also looking online for brass munsen rings, not cheap but if I can get a suitable size and a dovetail bar that might make a nice mounting option in keeping with the scope's vintage. Might be a hard find tho as the OD of the OTA is around 82-84mm so not a regular pipe size. Would give me the option to use the EQ5 or remount the rings on the EQ2. I guess if I pad the rings I could even try this on the TAL-M mount...

Internally I'd pull the paper in the OTA and flock I think but the OTA itself isn't in bad shape at all and I'd not want to lose the aged look of the scope, tho I might polish up the brass and see if I can lacquer coat it so it doesn't tarnish too fast. It's not a collectors item so I guess I could go mad and do something like swap the black leather for some rosso red leather but I quite like the black/brass look.

Any thoughts folks?

[DaveL59]

28 minutes ago, markse68 said:

Dang that’s a real bummer Dave  Have you had the objective out since the damage? Is it a doublet? Such a shame

No consolation I know but that Edmund Deluxe red finder I bought as an ebay bargain went in the bin the other day  The brass ep sliding focuser bit was corroded solid in the thick aluminium tube. I tried soaking in vinegar overnight and hot air gun but with nothing to get a decent purchase on all i managed was to shift in in a bit further 🤦‍♂️ Anyway the scientific application of targeted force (hammer and drift) resulted in the crosshairs glass shattering inside and at that point it was a waste of time going further. Shame as it was an unusual and nice thing but very heavy for a finder tbh...

Good to hear you’re not giving up on it and look forward to it’s resurrection

 

 

Hi Mark

thanks but yeah, totally gutted. As soon as I heard that tell tale plink I knew the lens was toast. Spall goes around 1/3 from the edge in one large leaf. I'd tried to be so careful too, but that's the problem in some ways of this one. You basically have an ally tube inside an ally tube, very tight tolerance and fit. That's all that holds the lens in place, so working them apart just a little needed a lot of effort as I got it further apart that gave the lens just enough space to rock and catch at the edge and... drat!

I've tapped the sections gently back together now so I can at least have a try of the scope once clouds permit. Daytime it looks pretty OK in fact which was a surprise, but I expect a very different result under stars or the moon. Be nice to get an idea of what it WAS capable of tho before my ham-fisted efforts and I have another go and maybe make the lens even worse.

There's a possibility that its a single lens, depending on just how old it is, but I think it probably is a cemented doublet, certainly isn't air-spaced as the lens moved as a single mass and no sign of any spacers.

Shame on that finder, I guess we roll the dice and sometimes get unlucky with our vintage purchases. The journey is fun though if a little heartbreaking from time to time. Think so far I've been pretty lucky given the number of binos and now scopes I've accumulated  

 

Edited July 17, 2020 by DaveL59

[MarkAR]

Unless the leather is rotted I would clean and treat it to revitalise it.

Laquer may or may not be a good idea for the brass, if it was something special I would have considered gold plating to save constant polishing.

Good luck with the search for a suitable lens replacement, would be ideal to get the right size but if not I might be able to machine something to make another lens fit. Could be possible to make something for either a target or smaller lens.

[DaveL59]

thanks Mark, yes I think the existing leather looks ok so will treat that with a clean and feed. The brass I'll see depending on the lens solution, not sure how a more recent 80mm cell would sit on the tube or if the lenses are just undersize of 80mm. The latter gives the option to refit as-was with great care, perhaps. Or if the cell is sized to fit over an 80mm tube then that could with but render the existing dew shield redundant and I'd need to try source a replacement brass tube to suit.

Time will tell where I end up on this mystery tour but there's always hope  

Looking like the sky might stay fair tonight so far so am hoping I'll get a chance to point the new cloud generator at it and see some shiny sparkly things and get a vague idea of how it might have performed, maybe even see that elusive comet  

[DaveL59]

So tonight I popped the EQ5 outside in the garden and bolted this vintage 3-incher onto it, hoping for some planets and to see how bag things are with that chunk out of the lens. Original brass EP of unknown FL and a Meade MA40 which are the only 0.965's I currently have. Hoping for good but bracing myself for marred views. So how did it go?

Well, I've just seen Jupiter and 2 moons as they rose above the rooftops, nice and sharp with both the brass eyepiece and the MA40 0.965. They need refocusing when switching which takes a bit of getting used to with a drawtube, but WOW! Could even make out that the planet had slight banding. Of course it's now tracked behind the skeleton oak tree before I could try refining my technique.

Then Saturn rose just above the rooftops and bingo, nice and clear too, can see the rings but without being able to push the mag obviously it was small, but the rings are indeed distinct from the planet. Couldn't make out any moons so far tho.

Sorry for the lousy first pics from phone at eyepiece on this vintage scope, with no eyecups on either eyepiece its not easy to get the camera positioned well by hand and of course me focusing the scope with no glasses so would be a tab out probably too.

I have to say that apart from when out of focus, that chip in the lens doesn't seem to aflict the image at all, quite a surprise. Tho I expect on a big and bright target like the moon that'll be a different story. Still, having planned that I could pop the Tal100RS on if it was real bad, I'm pleasantly surprised and very pleased. This old scope gives very nice views indeed, ta very much! So, for sure all is not lost on this one 😄 

[Cosmic Geoff]

You could blank out the chipped part of the objective with black tape etc. That should improve the contrast. I did this with a vintage Ross 40mm scope that arrived with a spall at the edge of the objective. The aluminium lens cell and glare shield parts would not undo - somebody already tried.

[DaveL59]

1 hour ago, Cosmic Geoff said:

You could blank out the chipped part of the objective with black tape etc. That should improve the contrast. I did this with a vintage Ross 40mm scope that arrived with a spall at the edge of the objective. The aluminium lens cell and glare shield parts would not undo - somebody already tried.

Been thinking that same thing Geoff, I've some water based matt enamel and also some paint pens so I could carefully paint that section at some stage. Was very impressed with the view it gave though and it didn't affect the views of the planets or stars at all even panning across the affected area. Considering the age of it I can imagine the previous owner spent many a happy hour viewing the heavens above with this scope  

On reflection am also thinking along the lines of working some brass strip or half a brass munsen ring fitted to the wood carrier to tidy the overall look. Keep as much of the original as I can, as it were.

[MarkAR]

15 hours ago, DaveL59 said:

Or if the cell is sized to fit over an 80mm tube then that could with but render the existing dew shield redundant

Might be possible to split the shield and solder a strip in to make it bigger.

 

[DaveL59]

19 minutes ago, MarkAR said:

Might be possible to split the shield and solder a strip in to make it bigger.

 

Had thought that's a possible option, tho it's 2-layer, outer is brass and the inner white non-ferrous likely ally and that inner forms the front part of the lens ring. A matching ally tube fits into the brass very tight, forming the lower lens ring. I am thinking though it it comes to it to buy a sheet of brass and try making a replacement shield to suit a replacement lens cell. The inner would be flocked anyway after all, but how well I could roll sheet metal by hand is another matter of course, bound to look well amateur I expect but you never know 😄 

I might have another look at separating the lens holder/shroud in the next couple days now it's had it's first light outing with me last night then I can have a closer look at the lens. After that it'll be a while before I can try owing to the amount of effort needed to turn/move the parts. Kinda nervous to dig this hole any deeper at the moment though, given it's quite usable as-is do I risk rendering it scrap until I have a lens I can replace it with...

[DaveL59]

ooh, just bought an old Vivitar metal lens cap, 85mm ID which should do nicely for the existing brass shield and help protect the lens (or the conservatory from catching fire with the sun glinting down the scope!). 

ahhh the slippery slope beckons once more... 😄