How to dis-assemble TV 8-24 zoom ?

[skybadger]

Hi all

I have the TV8-24 zoom and while kept in the obbo it's grown a bit of internal mould. I'm trying to work out how to safely did-assemble it but , while I have top ring unscrewed I can't find where the bottom ring comes off . Any ideas ? After that I can clean the optics and everything is good. 

[DaveL59]

not owning anything as posh as TV nor a zoom eyepiece I can't help a lot in terms of how you disengage the rings, do they not have the usual notches or pin-holes to engage a lens spanner?

One thing I would caution tho, no idea how these eyepieces are built but camera zooms are non-trivial to reassemble as you need to get the mechanism assembled right as well as the lenses set correctly. Take lots of pics as you dismantle to help get it back together after  

Edited July 9, 2020 by DaveL59

[John]

I don't know the Tel Vue 8-24mm zoom internals (it is the same as the Vixen LV 8-24 zoom) but here is a Baader 8-24mm zoom strip down which might give you an idea what to expect:

https://roslistonastronomy.uk/be-afraid-be-very-afraid-baader-8-24-zoom-lens-stripdown

I did another zoom a couple of years back and they are complex and fiddly things mostly because of the sliding mechanisms which are greasy and use tiny nuts and bolts.

There are 7 glass elements I think, as well.

[johninderby]

I took apart a broken Celestron (Vixen) 8-24 zoom once to see if I could fix it. The mechanim had come apart inside. An amazing amount of tiny and fiddly little parts in there. 🙀🙀🙀

Never could get it to go back together though and it ended up in the bin. 🙁

Edited July 9, 2020 by johninderby

[skybadger]

Yes to the risk, no to not being the same as the baader, as far as I can see. I have read that strip down before posting here. 

Other than that I'm fairly good with these helical mechanisms..on e I can see a way in without breaking it. 

Cheers

 

[Louis D]

How about baking it in the sun to kill off the mold via intense UV?  I know our Texas sun works wonders on such things.

[DaveL59]

UV would kill it, tho a UV lamp might be simpler given the grey cloudy days here in the UK at the mo. I zap my binos etc periodically to prevent growth as well as storing with silica-gel sachets.

[Don Pensack]

Killing the mould with UV light wouldn't eliminate the haziness on the lenses, though.

At this point, it's take it apart or throw it away.

Better to take the chance to clean it at this point.

[skybadger]

That's where I am. It's easy to clean off, if only it was as easy to access.

[John]

Looking at photos of the bottom end of the zoom, the 1.25 inch barrel and the chrome flange seem to be a single piece ?

I would guess that the whole thing would unscrew from the black body of the eyepiece but presumably it won't budge ?

[skybadger]

I got the top end of the eyepiece to unscrew but I am suspecting that the bottom end also unscrews, due to the lack of the zoom barrel shifting or exposing any screws.

I suspect that the silver bit unscrews from the base  but i just might break it trying.

 

 

[Louis D]

29 minutes ago, skybadger said:

I got the top end of the eyepiece to unscrew but I am suspecting that the bottom end also unscrews, due to the lack of the zoom barrel shifting or exposing any screws.

I suspect that the silver bit unscrews from the base  but i just might break it trying.

It's probably just got a bit of thread-lock on it to keep it from unscrewing during zooming.