ED80 focus problem

[bloodhound31]

Hmmm...I must be missing something.

My eyepieces should all work ok in the ED80, regardless of whether they are 12 mm or 40mm, plossl or otherwise shouldnt they?

I have wound the focusser all the way out and the focus stops short of full focus.

When I pull the eyepiece out all the way until it is about 5 to 10mm out of the holder, it is focused.

What am I not doing right?

Baz.

[Dennis]

Hi Barry

Sadly, like me, you have discovered not so! With my WO 80mm EDII and a WO 2” diagonal, most of my eyepieces come to focus using the supplied WO 2 inch extension.

However, for my Baader 21mm Hyperion, I need to use the Televue 3 inch extension tube, and the whole shebang ends up a little shaky as you can grab the extension tube and wobble it up and down. The wobble is in the sheer cantilever effect on the WO focuser, not in the nicely made Televue extension.

Cheers

Dennis

[[1ponders] (Paul)]

Are you using a diagonal or using it straight through Baz?

[bloodhound31]

I tried both mate... I think Dennis may be right. I may need an extension tube.

[casstony]

Barry, have you tried a 2" diagonal? The 2" will have a longer light path than a 1.25" diagonal.

[bloodhound31]

No Tony. I have the 1.25 that I have always had for the Celestron. Everything fits in, just nothing works. There's nothing I can do about it now on a Sunday night. I will have to turn down an extension tube on the lathe this week.

Thats the only way I can see a solve here.

Baz.

[bloodhound31]

I turned down an extension tube from aluminium. Problem solved. Thanks for your ideas people!

Baz.

[Dennis]

Nice work Baz. How will you blacken the inside of the tube to minimise light scatter?

Cheers

Dennis

[bloodhound31]

I can use a scotchbrite pad and then prime and paint, or I know a guy who can black anodise it to ten microns for me.