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Monolux 4366

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#1 ftwskies

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Posted 27 October 2016 - 11:54 AM

Do you remember when your first "project" scope arrived?  That heady mix of anticipation and trepidation...  The thrill of discovery as you carefully unpacked it, not knowing exactly what you'd find?  The musty smell of old cardboard, the dinge of accumulated dust, rust and grime...

 

Well, that was my night last night.  My Monolux No. 4366 arrived via FedEx out of Albany, NY yesterday, and after I got home from church I waited 'til the kids were in bed to pour myself a finger of bourbon and gleefully unwrap my present...

 

gallery_240021_6729_85839.jpg

 

gallery_240021_6729_151267.jpg

 

gallery_240021_6729_32182.jpg

 

gallery_240021_6729_80036.jpg

 

 

First impression:  This thing's gonna take some work.  Unlike my time-capsule Milben, this scope's got some miles on it. 

 

As far as I can tell, I've got a complete kit.  :hmm:  The seller (or their source) basically shipped me a Big Bag o' PartsTM -- the assorted lenses, tubes, collars, etc. that apparently comprise the finder and accessories.  "Some assembly required, batteries not included!"  :lol:   It seems I've the makings of an oddly constructed singlet-objective 5x24 finder, a 2x Barlow, an image-erecting tube, a prism diagonal, two Huygens EPs (a 12.5mm and a 6mm), a sun filter, and one or two extension tubes (?).  Oh -- and a small ~1/4" metal rod with strange bullet-shaped concavities at each end that does Jove-knows-what.  :scratchhead:   Anyhow, the various assorted lenses appear to have survived the trip :praying: , but are liberally smeared with grime and dust.   The objective looks a little milky, but is otherwise clear and undamaged.  (I tried to remove the shade and cell with my bare hands to get a closer look, but neither would budge.  I didn't want to force it.  All in due time, I s'pose.)

 

I'm guessing that the 4366 was sort of a budget model; instead of a wooden crate it has a nice, sturdy cardboard box with a leather carry strap.  Also, there there's no tray holding the tripod legs together -- in fact, in the illustration of the assembled scope that's included on the one-sheet instruction manual the tripod tray has been scribbled out -- I'm guessing this was done at the factory.  There are some other odd details for me to unravel,too -- like the two (not three) finder scope adjust screws.  And the way the scope mounts in the saddle -- instead of knurled knobs on each side, there's a fixed bullet-nosed bolt on one side that mates into the left side of the OTA, and and a knob on the right side to cinch it down.  At first blush the whole thing looks make-shift, but on closer inspection that parts all look factory made-for-purpose.

 

gallery_240021_6729_57751.jpg

 

gallery_240021_6729_107857.jpg

 

Guys, I'm gonna have soooOOOOoooo many questions... 

 

Just for starters:  Can anyone help me date this scope?

 

My gut is telling me mid-late 60's, but there's no JTII sticker, nor any of those little round JTII tags in the box, so it's just a hunch, I guess.  All metal construction, plus the apparent age of the box coupled with the font/logo styles, etc.  Not a hint of styrofoam in the box, either, but that may have been discarded previously, as the entire kit was wrapped in bubble-wrap inside the box and the tripod came pre-assembled.  I do have one other potential clue:  A blank order card from one Compass Instrument & Optical Co., Inc. of 104 East 25th Street in New York.  (No zip code - maybe that's also a clue?) 

 

gallery_240021_6729_50532.jpg

 

NOTE:  According to justia.com, Compass Instrument & Optical Co. owned the Monolux, Cadillac (binos), Monoscope, Compass and Panther brands.  FWIW, it looks like they're still around, now known as Compass Industries.  They sell knives, compasses, binoculars, magnifiers, stopwatches, pedometers, etc.


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#2 paulymo

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Posted 27 October 2016 - 12:10 PM

Very cool!  Yes I remember the day I brought home my vintage project scope (it was only about a month and a half ago!) and how lucky I was that I didn't have the kids or anything better to do that day  :grin:

 

Can't help with the dating of it but am looking forward to seeing pics of the rehab and hearing the first observation report.

 

Congrats!

 

Pauly


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#3 ftwskies

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Posted 27 October 2016 - 12:23 PM

Thanks, Pauly.  I'll be adding pictures and documenting the restore here on this thread.  I'm sure I'm in for an education / adventure!  :grin:

 

According to Wikipedia, the mail-in card I have uses the old district/zone format ("New York 10, N. Y.") that started in 1943.  ZIP codes started in 1963 but weren't mandatory until 1967.  That means (to me) that the card was printed before 1967 at the latest.


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#4 paulymo

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Posted 27 October 2016 - 01:03 PM

Nice detective work!  And given that Compass probably only ordered those cards printed once a year or so and that they wouldn't have ordered cards they knew could be obsolete when being used, I'm guessing at latest '65-'66.

 

Pauly



#5 Joe1950

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Posted 28 October 2016 - 08:27 PM

This was my first scope at 8 years old, 1958 (not the actual one but the same) Just got it a few days ago.  Not a project scope - excellent condition.

 

 

 

 

Monolux 50x50 Spotting Scope (used for astronomy) #4346.

 

 

Had a great time with it for many years.


Edited by Joe1950, 28 October 2016 - 08:29 PM.

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#6 rseven

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Posted 28 October 2016 - 10:30 PM

I bought a Monolux 60mm scope similar to this as a kid. It had some really sweet glass. Quite frequently I could crank it up to 175x with clear images. Of course the sky was a lot clearer 50+ years ago.

Very nice classic scopes. Thanks for sharing.
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#7 ftwskies

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Posted 30 October 2016 - 09:17 PM

Okay, I have another question.  Could sure use some help from our resident experts....

 

Through a process of deduction and some experimenting using my C90 I was able to get the accessories reassembled in working order, so now it's just a matter of cleaning and restoring.

 

I'm working on the 5x24 finder first.  It has a double-convex singlet objective that rests in the rear of the shade, and the tube threads in behind it.  The eyepiece is constructed from two double-convex singlets with a spacer tube between them.  A field stop holds them into the threaded eyepiece, which threads into the rear cell so you can focus the finder.

 

gallery_240021_6729_32902.jpg

 

First I had to clean the finder's objective; it was the only bare lens that was included in the Big Bag O' Parts.  Luckily it survived storage and shipment without damage, but it was crusted with some sort of hardened clear goo -- maybe tree sap or dog slobber or something, who knows. :lol:

 

 

gallery_240021_6729_46828.jpg

 

Lens cleaner wouldn't dent it, and neither would soft dish soap under running water, even with gentle application of the ol' thumbnail, so I soaked it in boiling hot soapy water for two minutes and that softened it up nicely; finished up with lens cleaner and Kimwipes and it's crystal clear now.

 

With that done, I turned my attention to the eyepiece.  The field stop didn't want to come out at first; someone had dribbled a spot of yellow glue on it that was gumming up the internal threads.  (Poor man's Locktite? :ohgeeze: )  I used thin sheet steel as a spanner and was able to slowly torque it out.  I was able to get all the dried glue out of the threads using a sharp dental pick followed by a swipe of adhesive-remover solvent.  (Love that stuff!)  A thin coat of white lithium grease on the threads returned smooth focuser action.  Luckily the eyepiece lenses weren't as dirty as the objective; a little lens cleaner and some Kimwipes got those little guys sparkling.

 

With all threads cleaned and lightly greased, I was able to reassemble the finder.  I noticed that even with the shade screwed down tight onto the tube, the objective still rattles around a little.  As far as I can tell it's slight lateral looseness, not tilt, so it shouldn't be too big a deal.  Still, right now I'm thinking this was a pretty poor design.  Is it possible there's a piece missing?  Some sort of gasket or stop or something?  Seems kinda hokey to me to just rest the bare lens on top of the tube and screw the shade down on top of it, but that appears to be the design...

 

Anyhow, I put it back together and it looks just like the picture in the instructions.  I took it outside to test it out on some distant targets and...

 

Uh-oh.  :shocked:

 

I can't get it to come to focus.  The eyepiece is threaded all the way in, but it seems to still want to be a lot closer to the objective than the tube allows.  The tube is about 4" long, but if I freehand the eyepiece and the objective (without the tube) they have to be about 2" apart to come to focus.  I'm pretty sure all three lenses are going to be symmetrical, right?  I did try flipping the objective anyways, but got pretty much the same result.

 

Any ideas?   :help:


Edited by ftwskies, 30 October 2016 - 09:20 PM.


#8 Bomber Bob

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Posted 30 October 2016 - 09:22 PM

The finder should have an aperture stop behind the simple lens - that's why it's loose.  I'll look through my spare parts.  I may have a better grade finder you can adapt to your existing tube...


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#9 ftwskies

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Posted 30 October 2016 - 09:56 PM

Gee, thanks - that would be great, JW!  :bow: 

 

I'm curious to know more about this aperture stop, though, if you don't mind.  Like I said above, I got a Big Bag O' Parts with this scope, so maybe I'm overlooking something.  Can you describe it, or does anyone have a picture of what it looks like?  I think Chuck was saying he did some work on one of these finders recently that had the same singlet objective as mine...



#10 Chuck Hards

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Posted 31 October 2016 - 08:52 AM

Could it be inside the finder tube, still?



#11 ftwskies

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Posted 31 October 2016 - 12:28 PM

Nope.  I had that thing completely disassembled yesterday -- it was just a smooth empty tube with external threads at the objective end and internal threads at the eyepiece end.  A spacer or aperture stop would have to either thread onto the inside of the shade before the tube threads in behind it or else rest in groove inside the shade with the lens (in which case it's not being much of a stop).  If you look closely at the shade in the picture above you can see a small groove at the base of the internal threads where the lens rests when the tube is screwed in.  The lens is almost exactly the same diameter as the OD of the tube.  You can rest the lens on the top of the tube and thread the shade on down over it and it captures the lens -- just not snuggly, even when the shade is fully tightened down.

 

I can live with the rattle (or fix it easily myself), I only mentioned it as a potential clue to the focus issue.  That's what I'm really trying to figure out -- I'm not sure how it's possible that the parts I have ever built a working finder... But they must have, right?  So I must be either missing pieces, or doing something wrong (lens orientation or something). 

 

I can always improve the performance by replacing stuff, but I'd really like to restore this thing to working order using as much stock stuff as I can.  From there, if I want to swap stuff out to improve it, fine, but I'd prefer to have a fully functional stock scope as a baseline for any mods.



#12 Bomber Bob

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Posted 31 October 2016 - 01:11 PM

I looked through my boxes of odds & ends for any 5x24 finder parts -- No Joy.  I did find this 1980s Mizar (?) with an achromatic cemented objective and glass eyepiece (possibly Erfle!).  It needs some LUV - and crosshairs! - but gives decent views.  The base has a 22mm bolt spacing for mounting to a scope.

 

6x30 LER Japan Finder w Bracket S02.jpg

 

If you want to give it a try, just let me know.  Telescope Warehouse has this 5x24 --> http://shop.telescop...57&categoryId=8   It's similar to the finders on the basic vintage imports of the 60s & 70s.


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#13 ftwskies

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Posted 31 October 2016 - 02:18 PM

Thanks, JW, I appreciate the offer.  That little Meade finder might actually be worth picking up if for no other reason than to tinker with it and see if it's constructed the same as mine.  From the tiny little picture it looks just like the one I'm working on.

 

When I get a free evening I'm going to try getting my finder to focus before I give up on it.  It occurred to me that maybe it focuses out at infinity but not at the treetops 200ft away like I've been trying.  I'll have to find some way of unobtrusively and temporarily marking one side of each of the three lenses so I can keep track of their position and orientation as I run through different configurations, just in case the lenses are not symmetrical.  TBH, the eyepiece lenses are too small to tell for sure, but the objective does appear to my eye to have a slightly smaller radius on one side than the other...

 

Gosh, you were right -- this classic scope stuff isn't for the faint of heart!  :lol:


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#14 ftwskies

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Posted 01 November 2016 - 08:26 PM

So I took the finder out tonight when I got home from work, just to see if I could get it to focus on a more distant target. (On Sunday I had just tried focusing on the trees across the street, so tonight I tried using Mars as a target.).

No such luck.

Then it occurred to me: Is it possible that the reason the objective is loose in there is because I'm missing a lens? Could it have been a doublet originally? It seems like a doublet that small would have been cemented, so it's probably not likely... But I wonder...?

#15 Bomber Bob

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Posted 01 November 2016 - 08:38 PM

It could have been an achromatic.  I think one of my 5x24 finders has a cemented doublet.  I know the 40mm Astro Optical finders I have are air spaced.  That's a problem with vintage scopes -- changes made by previous owners.



#16 ftwskies

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Posted 01 November 2016 - 08:47 PM

I guess I could get one of those cheap 5x24 finders and replace this objective with the new one... Or shop for a nicer replacement from a glass house like Edmund...

#17 ftwskies

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Posted 01 November 2016 - 08:53 PM

Hrmmm... But that's a problem. How can I figure out the FL that I need to work with this finder? Is it standard for all 5x24s?

#18 ftwskies

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Posted 01 November 2016 - 10:24 PM

Okay, I pulled out ye olde trusty caliper and took some numbers.

 

The shade has a groove for the objective that is 3mm wide even when the shade is fully screwed on tight.  The edge of the objective I have is only 1mm wide.

 

The objective is double convex, 24.29mm in diameter.  It's 4.32mm thick in the middle, and like I said, 1mm thick at the edge.  It has a 43mm FL, which is a problem, because the finder tube is 95mm long.   The EP focal plane is obvious because of the four notches in the bottom of the field stop where the crosshairs used to be.

 

So I'm growing more convinced that this thing had an air-spaced achromat objective.  And that gives me a sad, because it was probably a pretty nice lens when it was intact.



#19 ftwskies

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Posted 02 November 2016 - 09:40 AM

This morning I ordered the stuff I need to fix the finder; I've got a lens on order from SS and a new finder on order from Telescope Warehouse as a "Plan B".

 

So... On to the next question -- and this one's really puzzling me.

 

Any idea what this piece is for?

 

gallery_240021_6729_48924.jpg

 

gallery_240021_6729_48619.jpg

 

In case it's not clear form the pictures, it's an aluminum dowel, roughly 3/8" dia. and 3-1/2" long, that's drilled out on each end.  Not threaded.  The only place I could find where it fits is between the screws on the mount yoke, but that makes no sense at all to me.  Any ideas?  :hmm:



#20 Stargoat

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Posted 04 November 2016 - 06:53 PM

This morning I ordered the stuff I need to fix the finder; I've got a lens on order from SS and a new finder on order from Telescope Warehouse as a "Plan B".

 

So... On to the next question -- and this one's really puzzling me.

 

Any idea what this piece is for?

 

gallery_240021_6729_48924.jpg

 

gallery_240021_6729_48619.jpg

 

In case it's not clear form the pictures, it's an aluminum dowel, roughly 3/8" dia. and 3-1/2" long, that's drilled out on each end.  Not threaded.  The only place I could find where it fits is between the screws on the mount yoke, but that makes no sense at all to me.  Any ideas?  :hmm:

That is exactly where the part goes. Have several early 1960 yokes from Circle T scopes and some still have this rod. Best guess it was used during original packing of the yoke to keep the side yoke screws in place during shipping as they had that thick grease on them.

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#21 ftwskies

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Posted 04 November 2016 - 07:20 PM

Hey, thanks! Wow, what a strange bit of kit that is. I can't imagine what purpose it really could serve... Unless maybe they were worried about the yoke getting squashed in the case or something? Seems like a pretty robust solution to an unlikely problem (since those cast yokes are pretty sturdy on their own).

See, I knew I could ask here at CN and someone would know. :)

#22 Chuck Hards

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Posted 06 November 2016 - 03:10 PM

Okay, I pulled out ye olde trusty caliper and took some numbers.

 

The shade has a groove for the objective that is 3mm wide even when the shade is fully screwed on tight.  The edge of the objective I have is only 1mm wide.

 

The objective is double convex, 24.29mm in diameter.  It's 4.32mm thick in the middle, and like I said, 1mm thick at the edge.  It has a 43mm FL, which is a problem, because the finder tube is 95mm long.   The EP focal plane is obvious because of the four notches in the bottom of the field stop where the crosshairs used to be.

 

So I'm growing more convinced that this thing had an air-spaced achromat objective.  And that gives me a sad, because it was probably a pretty nice lens when it was intact.

 

Something's not right.  43mm is too short for the focal length on this finder.  It's been a while since I replaced the objective in the one I gave away with an achromat, but I seem to remember the FL being closer to 97mm or 99mm, something like that.  The focal length will be the physical distance between the rear of the objective and the plane of the cross-hairs.  Should be closer to four inches than 43mm.

 

Going from memory here, but I'm pretty darn sure 43mm is too short.  



#23 ftwskies

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Posted 06 November 2016 - 11:33 PM

You're right as usual, Chuck.  The focal length of the finder objective should be 95mm, but the focal length of this one double-convex lens is indeed 43mm.  Between that and the looseness of the lens in the assembled finder I've concluded that I'm missing the other half of what was originally a doublet.  Anyhow, I've got a new 95mm FL lens from SS coming this week to replace it.  


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#24 ftwskies

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Posted 10 November 2016 - 09:57 PM

Well, my finder lens from Surplus Shed came in today.  It's a single DCX lens with 95mm FL.  Uncoated, far as I can tell. The 1" diameter makes it a perfect drop-in replacement.  It's thicker than the remaining crown lens from the original achromat but still not quite as thick as the complete pair would have been, so there's still a tiny bit of slop in the retaining groove that I plan to fill in with a soft foam rubber gasket.  The finder comes to focus now with the eyepiece almost all the way in.  (I could've used a 100mm FL lens instead but I couldn't find one.) But hey, it works!  Granted, it's an uncoated singlet so it's got a ton of color, but at least it gives an image that can be used to aim the scope at the Moon, planets or a bright star.  I'll probably keep an eye out for a suitable achromat to replace it down the road, but for now it's functional.

 

Here's the even better news, though:  Skies were clear tonight with a gibbous moon, so I took the scope (which I've tentatively named Molly) out for first light.  And I think we have a winner!  Aside from some light ghosting which I think is likely due to the grubby glass, I got some really crisp, color-free views of the lunar limb at 18x (using my 40mm Meade MA) and 39x (my 18mm Celestron Kellner)!  I ran out of time for tonight but I can't wait to see how it does at higher powers, especially once I get all the glass cleaned up.  Might prove a little tricky since I'm having a heck of a time getting the front cell off the tube.  The shade comes off fine, but the cell won't budge. In fact I have to be careful how I grab it with the shade off because the retainer ring wants to loosen under my hand and I can tell (because it's dusty) that the crown lens wants to spin with it!  I can't be certain that the flint is rotating as well and I don't want to mess up the alignment -- especially since I don't yet know whether there are any alignment marks on the lenses.  But at least I think the glass in this thing is gonna make the refurb efforts rewarding. 


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#25 ftwskies

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Posted 21 January 2017 - 01:50 PM

I'm getting started in earnest now with the refurb on this 'scope.  Last night I did a photoshoot to fully document all the nooks and crannies on this kit, both for my records and also to illustrate any questions that come up as I go.

 

One thing I noticed was the poor quality of the castings on some of the parts.  The optics are good vintage Japanese, but some of their metalwork was iffy.  Check out the voids in this lens cell from the included 2X Barlow; the first pic shows a big void in the threads that attach the nose piece, and the second picture shows the lens stop threads (on the flip side of the cell):

 

gallery_240021_6729_68426.jpg

gallery_240021_6729_21925.jpg




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