Brass compression rings are a pest.

[ollypenrice]

Interesting discussion on Cloudy Nights about a Moonlite focusser that won't work because of the compression ring not being compatible with the chosen diagonal...

Which brings me back to what I said in my Meade 127 review. I hate these compressin ring devices. They are not set to any standard and so some accessories have grooves incompatible with some compression rings. I have had a camera fall out, filter wheels refusing to sit square in draw tubes and constant fear of more droppings out.

Have you ever seen an eyepiece damaged by a grub screw?

Grrr, who invented the wretched things and why? Come on, confess!!!

Olly.

[AndyH]

Compression rings would be fine if not for these bloomin' undercuts.

I dislike the latter

Andy.

[ollypenrice]

I guess you're right. We need one or the other but not both!

Olly

[dave cook]

I can understand different manufacturers having different diamensions for compression rings and undercuts but not a manufacturer who produces incompatability in its own equipment. After purchasing a WO 28mm UWAN I found that the eyepiece stood proud of the WO diagonal by 6mm it was designed to fit in and of course the ring and the undercut were out by the same amount.

Complaints to WO via the seller produced the following from WO.

"We have tested an eyepiece in a diagonal, turned it upside down and shaken it and it did not fall out" What do they thgink I'm doing out there at midnight, the Oakey Cokey?

Dave Cooke

[ZOG]

I wonder why the makers don't adopt the collett approach as used in capstan lathes.

Those seem to hold heavy lengths of bar more or less dead central.

[ollypenrice]

I'd just settle for what we had to start with!

Olly

[FLO]

Grrr, who invented the wretched things and why? Come on, confess!!!

Olly.

Televue .....

Actually, I'm not sure that they invented it but they certainly popularised it.

I wonder why the makers don't adopt the collett approach as used in capstan lathes.

Agreed

[Milamber]

I wonder why the makers don't adopt the collett approach as used in capstan lathes.

Those seem to hold heavy lengths of bar more or less dead central.

That'll be the Takahashi stuff you mean then? Thing is, would you be prepared to pay for it?

Arthur

[ZOG]

I'm sure it could be done cheaper than Takahashi Arthur, after all, on a smaller scale the system is used in some automatic pencils.

[johninderby]

Baader does a self centering one in the 1.25" size called the Click-Lock. Part of their modular diagonal system. About an 1/8th turn on the locking ring clamps the eyepiece in three places.

John

[ZOG]

I'm sure I saw some photo visual Barlow not so long ago that used the system, I cant remember the make, but it came in nice colours

[Ben Ritchie]

I'm sure I saw some photo visual Barlow not so long ago that used the system, I cant remember the make, but it came in nice colours

The AE ones do - works very well

[Tiny]

I have had no trouble with mine but are they an advantage over single or double screw fittings. I always presumed there was an advantage but what is it?

[johninderby]

Yes the A&E barlow, but the problem with that design is that it doesn't work with a WO type tapered barrel. It can't compress enough to grip the tapered part of the barrel so the eyepiece just flops around in the top of the barlow unless you pull the barrel half way out so that the straight part of the barrel can be clamped.. The Baader uses a three point cam locking system.

The advantage of the brass compression type is that it doesn't mark up the eyepiece barrel. Ever tried selling a top quality eyepiece with marks from screw type clamps? It can knock the price right down.

John

[ollypenrice]

No one should sell a top quality eyepiece! And if anyone out there has an Ethos with a marked barrel that they feel has to go cheply, well I'm yer man!

Olly.

[ZOG]

Isn't it pedantic ?? People buy eyepieces to use them and screw clamps mark barrels, it's a fact of life and no reason for not paying the price for quality optics.

[johninderby]

Yes it's stupid that anyone should bother so much about a couple of little marks. But for instance when I sold a few Naglers recently to fund buying two Ethos eyepieces I got so many enquiries asking "are there any marks on the eyepiece barrel" that I got sick of it and if I answered yes in the case of the one that did they would ask me if I'd take £40.00 or £50.00 less. Arrrrrrgh !!!!

John

[high25]

know them cue extension you can buy, twist grip things kinda like the quick release drill chucks .....no idea what the mechanism is called but its probably been mentioned here, seems a good idea and a much faster mre secure fastener over a compression ring it seems....... maybe. I dunno but i thought id throw in my thoughts .

Andy.

[ollypenrice]

John, anyone, everyone, if you have a super EP to sell and it has a barrel chewed by Lions... fear not. It will do very nicely here where, in my five first years, no one has ever scrutinized an EP barrel before deciding whether or not to look through it. I can't quite believe we are having this conversation. Aren't we supposed to be into the things that really matter?

Olly

[johninderby]

Hi

Yes I agree. Why someone would be so concerned about any trace of an eyepiece having ever been used when it is a second hand used eyepiece I don't know. Maybe they just want to look at it instead of through it.

John