37 replies to this topic

[LukaszLu]

I recently came across a copy of Polarex 114 in a rare BELI (BELIS?) branding version. Apart from the careful removal of traces of the Polarex brand (visible only on the plastic bag for the tube), it does not seem to differ from the standard model. The set did not include a tripod and mount, what you see in the photos comes from the standard Polarex 114.

Does anyone know which retailer sold this model under the this brand?

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[LukaszLu]

a few more pics...

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[LukaszLu]

well known, general view :-)

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Edited by LukaszLu, 07 May 2024 - 02:35 PM.

[deSitter]

Wow this is excellent! A really rare bird! The eyepiece adapter is the same as sold by Unitron for their 40mm Monochro eyepiece. Those two items were my first accessory purchases back in the day.

 

-drl

[Kasmos]

I recently came across a copy of Polarex 114 in a rare BELI (BELIS?) branding version. Apart from the careful removal of traces of the Polarex brand (visible only on the plastic bag for the tube), it does not seem to differ from the standard model. The set did not include a tripod and mount, what you see in the photos comes from the standard Polarex 114.

Does anyone know which retailer sold this model under the this brand?

Nice find. It's looks excellent. i love the unusual stuff.

 

There's a little information here (just above the photo of the Mercuius focuser)

http://www.company7....tron/notes.html

 

Links to other Belis

 

https://www.unitronh...ls/others/beli/

 

https://www.cloudyni...fans/?p=2613510

 

https://www.cloudyni...ly-not-unitron/

 

https://www.cloudyni...0900-telescope/

Edited by Kasmos, 07 May 2024 - 02:54 PM.

[LukaszLu]

No no - Monochro 40+adapter as well as mount and tripod are not the part of the find :-)

[Kasmos]

It's too bad the original mount and tripod were not included, mostly because I wonder if it's tripod was like Allan's?

 

On the plus side, it looks like it doesn't require any of your usual restoration techniques

[LukaszLu]

Unfortunately, I don't know anything about the tripod and the mount - the telescope was in a typical box that normally held both the mount and the tripod.

 

It did not require any special treatments - standard cleaning and grease replacement. There was a little more work with the eyepieces and accessories - they were quite dirty, although they seem to be in good condition. Only the Ramsden 25 mm is questionable as to whether it is original.

 

However, it turns out that even this can be risky. In the case of seized brass screws, one, even not very strong, movement is enough to tear off the head. Fortunately, this happened on the black painted flange into which the lens cell is screwed in - I simply glued the head back into place and it was not visible that it had been torn off. Maybe it was like that when I bought it - I didn't even feel any resistance, and the head fell off...

[LukaszLu]

Accessory set - the Barlow lens is missing, which was probably included in the set.

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[deSitter]

That's definitely the Unitron (by Tani?) 25mm Ramsden. What's the problem with it?

 

The 20mm Ramsden from my Monolux is also not great - lotta blue at the field stop.

 

-drl

[Kasmos]

I can't quite recall if most of them came with the Huygens 25mm or the Ramsden? I think the Ramsden. My circa '57 came with a 25mm Huygens.

 

Also, I don't think the Barlow is missing. I don't recall any of the 114s coming with one as standard equipment.

[LukaszLu]

Doubts about Ramsden arise from the fact that the black eye lens cover cannot be tightened to the end of the thread on the metal sleeve. This is because the housing of this lens does not hide properly in the sleeve, which is caused by the presence of an additional, internal sleeve holding the objective lens. It reaches to the edge of the galvanized outer sleeve, preventing the eye lens housing from being inserted. It's hard to believe that the manufacturer deliberately chose such an inelegant solution.

 

The set included a remnant of a Barlow lens - but of course it may have been placed in the case by one of the previous users.

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[deSitter]

Doubts about Ramsden arise from the fact that the black eye lens cover cannot be tightened to the end of the thread on the metal sleeve. This is because the housing of this lens does not hide properly in the sleeve, which is caused by the presence of an additional, internal sleeve holding the objective lens. It reaches to the edge of the galvanized outer sleeve, preventing the eye lens housing from being inserted. It's hard to believe that the manufacturer deliberately chose such an inelegant solution.

 

The set included a remnant of a Barlow lens - but of course it may have been placed in the case by one of the previous users.

I'm afraid I don't understand this - the barrel should have an integral field stop for a Ramsden (Huygens stops are internal). Is the eyepiece bumping up against that? Is the "field lens" (what i think you referred to as the objective lens) in the barrel or in the eyepiece housing?

 

-drl

[LukaszLu]

This is what it looks like. The field lens is fixed from the inside with a black-painted sleeve that reduces the diameter so that inserting the eye lens housing properly is impossible. This black inner sleeve should simply end about 1.5mm below the edge of the galvanized sleeve.

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[LukaszLu]

Eye lens housing correctly inserted into the sleeve (K 18 mm)

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[deSitter]

This is what it looks like. The field lens is fixed from the inside with a black-painted sleeve that reduces the diameter so that inserting the eye lens housing properly is impossible. This black inner sleeve should simply end about 1.5mm below the edge of the galvanized sleeve.

Which way is the convex side facing for the lens in the barrel? I wonder if this is some mashup of a Huygens and a Ramsden - the Ramsden field lens convex side should face the eye, and the flat side should face the sky. There is no field stop, and a 25mm Ramsden should have about a 20mm field stop near the far end of the barrel. I can't believe the barrel end is the field stop.

 

-drl

[deSitter]

Interesting - reviewing the catalogs, in the 50s the 25mm eyepiece was a Huygens, but in the 70s it is a Ramsden.

 

-drl

[Kasmos]

Former owners make all kinds of strange mistakes, so here's a long shot.

The diagonal's chrome barrel (with threads on it's end), also doesn't look right. I kind of doubt it, but Is there any chance it and the barrel on the eyepiece were swaped?

 

 If not you might also check the one on the Porro. 

[LukaszLu]

Strange as it may sound, a field lens does not have a flat surface at all. The very fact that it is locked with this internal sleeve, which cannot be removed with standard tools, shows that this is some kind of non-standard combination. In my opinion, this also rules out the version of an accidental sleeve replacement - this double sleeve does not fit any eye lens housing.

 

Interestingly, the eyepiece gives a great image. In the center of the field of view it is crystal clear, precise and without any traces of chromatic aberration. It's a bit worse near the edges of the field of view, where blurriness and slight aberration appear. Perhaps this is the best eyepiece in the set - the other eyepieces give clear traces of CA, which is somewhat understandable at shorter focal lengths.

[deSitter]

Strange as it may sound, a field lens does not have a flat surface at all. The very fact that it is locked with this internal sleeve, which cannot be removed with standard tools, shows that this is some kind of non-standard combination. In my opinion, this also rules out the version of an accidental sleeve replacement - this double sleeve does not fit any eye lens housing.

 

Interestingly, the eyepiece gives a great image. In the center of the field of view it is crystal clear, precise and without any traces of chromatic aberration. It's a bit worse near the edges of the field of view, where blurriness and slight aberration appear. Perhaps this is the best eyepiece in the set - the other eyepieces give clear traces of CA, which is somewhat understandable at shorter focal lengths.

OK this further indicates that this might be a mashup, because a Ramsden eyepiece always has a plano-convex field lens as far as I know. I've never heard of a Ramsden variant with a non-standard field lens. There is a "Symmetrical Ramsden", sort of like a Plossl but with simple lenses. That's the SR eyepiece in classics. There should also be a field stop slightly beyond the field lens in a Ramsden. On the other hand, a Huygens-Mittenzwey will have a concavo-convex lens with the convex side toward the sky, and no field stop.

 

How is the lens held in the barrel? I must say this is an interesting mystery!

 

-drl

[LukaszLu]

Well - it seems that the field lens was simply forced into the sleeve and that holds it in position. From the inside it is probably resting on the inner black sleeve. There is a field stop on the outside, but there is free space between it and the lens - it does not press against it and it seems that nothing other than the force of friction holds the lens in the right position. Anyway, I can't see anything like that - even with a magnifying glass.

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[deSitter]

That's correct - field stop slightly in front. Well, this eyepiece is just wonky!

 

-drl

[LukaszLu]

This is what it looks like - although it works very well!

[LukaszLu]

In the meantime, I made progress in the investigation of the mysterious remnant of a Barlow lens that was located in a charming box signed by Junghans.

 

The key to solving the puzzle was the unusual thread located on the edge of the diagonal sleeve. If this model was not equipped with Barlow as standard, it becomes clear why someone decided to make up for this lack by inventing a clever and quite convenient way to attach the lens. It is simply screwed onto the sleeve, obtaining a substitute for a typical design. It can even be unscrewed with the entire sleeve and used interchangeably with a regular, standard sleeve, making assembly and disassembly easier under observation conditions.

 

And... it works!

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[deSitter]

In the meantime, I made progress in the investigation of the mysterious remnant of a Barlow lens that was located in a charming box signed by Junghans.

 

The key to solving the puzzle was the unusual thread located on the edge of the diagonal sleeve. If this model was not equipped with Barlow as standard, it becomes clear why someone decided to make up for this lack by inventing a clever and quite convenient way to attach the lens. It is simply screwed onto the sleeve, obtaining a substitute for a typical design. It can even be unscrewed with the entire sleeve and used interchangeably with a regular, standard sleeve, making assembly and disassembly easier under observation conditions.

 

And... it works!

Yes I thought this was widely known. I have a Celestron shorty barlow (free with another purchase) where the barlow is in a cell with the same threads as a filter, so I can screw it onto my binoviewer. First one I've owned, but it reminded me of the Unitron barlow. I could attach this to my diagonal like this as well. You could do a timer test to find the magnification - time a star going through the field side to side across the middle.

 

-drl