Mystery ring

[Outcast]

I recently bought a secondhand Meade LX90 8" SCT.

As part of the package, I received 8 Super Plossl eyepieces, a 2x Barlow, CLS filter, 5 coloured filters & a moon filter.

In the case is a black ring, fitted with a knurled knob that screws through the ring, similar to an eyepiece holder. The ring is 1.25" internal diameter & about 5mm thickness, metal construct.

I have no idea what this is for, can anyone shed light on it's purpose please.

Thankyou

Carlton

[barx1963]

Sounds like a parfocalising ring?

[xelasnave]

Does it fit on an eye piece?
I think it is what Malcolm suggests.
So you use one ete piece and you find when you change to another you need to refocus but using the ring you dont move the focuser but only the eye piece and when focused secure the ring so you can switch between eye pieces without moving the focuser.
Alex

[Outcast]

Thanks Gents,

Yes it does fit on an eyepiece & after Malcolm's suggestion I googled parfocalising rings & agree that is what it most likely is. Hadn't seen one before.

Cheers

Carlton