flextube focuser problems

[dobbie]

hi all, as anybody had this problem with teleview ep's and the flextube dobsonian .

i recently changed my ep collection to televiews which i use with my ed80 then

the other night i dragged out the dob went to use the teleview 11mm and it would

not come to focus (not enough outward travel) i tried my other tv 8mm & 25mm with

the same result , as anybody got a easy solution for this and why its happened i suspect

its something to do with the focal length ?

thanks for viewing dobbie.

ps sorry if this is posted in the wrong place mods please feel free to move.

[Moonshane]

I suspect it is that these eyepieces focus well out.

there's a few things you could do.

- with a little slack left in the focus out travel, pull the eyepiece out a little to focus and clamp. if secure then this may be enough

- use a 28mm baader fine tuning ring screwed into the end of the 2-1.25" converter - this should allow that adapter to be held out enough like above

- buy a 50mm extension tube (might be too much though).

[Stephen]

All you need is a small extension tube to go between the focuser and the EP.

If I understand it correctly, Televue needs more out focus - just the way they are.

All EPs will come to focus at a different point.

[Odd Dob]

Lets get the hilariously embarrassingly stupid mistakes out of the way 1st. You *did* fully extend the flextube, yes?

[dobbie]

thanks for the input guys , except odd dob:D i had my dob for a few years now i think i have worked it out

ok the extenstion tube sounds the best and cheapest route , thanks once again even you odd dob i needed a good laugh:iamwithstupid:.

[dobbie]

"with a little slack left in the focus out travel, pull the eyepiece out a little to focus and clamp. if secure then this may be enough"

hi moonshane just replaced the bottoms of the tv's with longer shafts from old sw ep's and should work thanks again ..

[Moonshane]

no worries mate

don't ever do this with a 32mm TV Plossl as I noted a warning note in one I bought recently that this leads to all the lenses dropping out!

[dobbie]

Noted , might use a old barlow with the lens taken out ,

Sent from my HTC Wildfire using Tapatalk

[Moonshane]

also a good idea.