Loose elements in 8mm Starguider

[ScottS]

I've had my 8mm BST Starguider EP for a while now and it's been performing very well, but recently I've been using it and have noticed with the eyecup wound out, there is a set of elements inside that are loose and rattle in the housing.

Now, I've removed the barrel section and discovered that the loose elements inside the housing can be screwed back and forth as expected and that the rattling will stop if I wind them fully towards the barrel end of the EP.

My question being, is this the correct position for these set of lenses?

I,ve not had the chance to actually use the EP in the scope since the adjustment. Obviously I don't want inferior views from this EP just because the lenses are in the wrong position.

My other BST EP's are of a slightly different configuration at this end, so I can't tell from them.

Any help much appreciated.

Thanks.

Scott.

[RT65CB-SWL]

Does not sound, (sorry), good. Have a word from where you purchased it from and see what they say. If it was Alan from 'Sky's the Limit' I should not think there would be any problems.

[Peter Drew]

Most eyepieces have a thin slotted retaining ring to hold the lens elements firmly in position. If your eyepiece retaining ring is loose turn it in until the lenses stop rattling, this should be the correct position for them. 

[ronin]

One of the new BST's I got had a rattle from the bit that goes into the focuser, the element in that had come loose somewhere. I simply tightened it up and all is fine.

I would guess you have split yours at the centre of the main body, where there is one of the anodised rings. There is a slotted holder in there and it will need to just be tightened up.

Likely it was never done that much at assembly ahd during the shipping around the world has worked a little loose. Just take care to keep the internal lens clean and free from anything.

[ScottS]

Okay, thanks for the feedback. I'll have another look tomorrow.

[nightfisher]

For some reason the 8mm BST can suffer a rattle, best way to deal with it is to remove the eyecup and there is a slotted ring to tighten

[Donkeiller]

I find all my BSTs have developed a rattle at some point. Tightening the slotted ring is only a temporary fix.

My solution is to tighten the ring, then add a drop of superglue to lock it in position.

Works every time

[ChrisLX200]

I find all my BSTs have developed a rattle at some point. Tightening the slotted ring is only a temporary fix.

My solution is to tighten the ring, then add a drop of superglue to lock it in position.

Works every time

That - or nail varnish, which is a bit easier to remove should it be necessary to disassemble for cleaning. The rings should never be physically tight for fear of distorting the lenses, they are merely there to retain the components in position relative to each other.

ChrisH

[ScottS]

Most eyepieces have a thin slotted retaining ring to hold the lens elements firmly in position. If your eyepiece retaining ring is loose turn it in until the lenses stop rattling, this should be the correct position for them. 

It appears that winding the slotted ring out (towards the barrel/focuser end) cures the rattle. Does this seem right?

I find all my BSTs have developed a rattle at some point. Tightening the slotted ring is only a temporary fix.

My solution is to tighten the ring, then add a drop of superglue to lock it in position.

Works every time

Not sure I trust myself with that fix.

[AndyWB]

My 8mm developed a rattle - screwing the ring IN cured it. 

[LukeSkywatcher]

Most eyepieces have a thin slotted retaining ring to hold the lens elements firmly in position. If your eyepiece retaining ring is loose turn it in until the lenses stop rattling, this should be the correct position for them. 

As Peter said, most EP have small retaining rings inside which hold the lens in place. They can become loose and rattle. Its a very easy fix. You can tighten them with a wooden/plastic tooth pick or a set of tweezers. If using metal tweezers just be sure not t scratch the lens. Rubber tipped tweezers is a better idea. Basically whatever metal implement you use be careful.

IIRC the retaining rings are tightened by screwing them clockwise. There are two small grooves cut in the retaining rings to tighten it (opposite each other). Its best to use something that allows you to use both brooves at the same time. Tweezers allow for this to happen. Using only one groove may lead to it becoming loose again in the future.

Hope this makes sense.

P.S.~~~I would NEVER use glue or nail varnish to seal the retaining ring in place. If that was needed, do you not think the makers or the EP would have done that in the first place.

[ChrisLX200]

As Peter said, most EP have small retaining rings inside which hold the lens in place. They can become loose and rattle. Its a very easy fix. You can tighten them with a wooden/plastic tooth pick or a set of tweezers. If using metal tweezers just be sure not t scratch the lens. Rubber tipped tweezers is a better idea. Basically whatever metal implement you use be careful.

IIRC the retaining rings are tightened by screwing them clockwise. There are two small grooves cut in the retaining rings to tighten it (opposite each other). Its best to use something that allows you to use both brooves at the same time. Tweezers allow for this to happen. Using only one groove may lead to it becoming loose again in the future.

Hope this makes sense.

P.S.~~~I would NEVER use glue or nail varnish to seal the retaining ring in place. If that was needed, do you not think the makers or the EP would have done that in the first place.

Made correctly it wouldn't be necessary, loose tolerance on the threads means it might be...

ChrisH