2" Nosepiece wobbly...

[MikeWilson]

Well not completely wobbly but enough to cause a little bit of droop to set in. this flattener is held in place by the compression ring only.

(I'm trying to troubleshoot why my images aren't flat).

I reckon a 4mm metal parfocal type ring around this nosepiece will hold it flat against the focuser.

Does anyone know where I can find something that might do the job, or alternatively a different nose piece for the Televue TRF-2008?

Any ideas are warmly welcomed!

Mike

Sent from my mobile using TapaTalk (so please excuse bad grammar & spelling!) :-)

[TheThing]

Astroboot? They have loads of parfocal rings.

TheThing

Sent from my iPhone using Tapatalk

[Psychobilly]

I had a problem were a compression ring lined up with the edge of an undercut .. I ended up building the undercut up with tape...

Peter...

[ollypenrice]

When I see a brass compression ring I tear it out with needle pliers and hurl it into the wilderness. And that includes my all-Takahashi setup which still wasn't compatible with itself! The rig distorted and refused to release the nosepiece. As Billy says, the most common problem is the compression ring mis-matching the undercut.

I ought to stress that this vandalistic attitude applies only to my own kit and not to that of other people!! Your compression rings are safe, gentles all...

Olly

[Merlin66]

I never rely on the fittings holding anything square to the optical axis -been there done that...Now I use a separate support bar/ frame to hold everything. May appear overkill - but how many nights do you want to waste??

[Psychobilly]

Nice functional engineering Ken - can't fault it..:icon_salut:

Peter...

[MikeWilson]

Thanks for your input Hugh, Olly, Ken.

I am staggered by what Ken's made. That's impressive work there! It also goes to show what a terrible terrible connection the compression ring is. I can't possibly hope for a perfectly orthogonal fit with one in place.

Having said that, the Baader Clickzoom nosepiece does fit all the way into the focuser and the ring holds it *** and square, so it can be done. Just not by this particular Televue and focuser. It's a shame that there's no screw fitting (although this focuser is threaded...).

Hugh, I did check AstroBoot but I wasn't sure if they'll do the job - They might be too small. Still, if I can get two par focal rings, I may be able to get close enough to filling the 4mm gap. I've ordered one for now, just to see.

Thanks again,

Mike

[Starlight 1]

Cut open a coke can and use it as a shim.

[spaceboy]

I never rely on the fittings holding anything square to the optical axis -been there done that...Now I use a separate support bar/ frame to hold everything. May appear overkill - but how many nights do you want to waste??

WOW!!!

[ollypenrice]

Blimey, Ken, THAT is an attachmnet, as they say...

The plane is fully adjustable or did you just get it right?

Olly

[MikeWilson]

Cut open a coke can and use it as a shim.

That's the best solution for me, I think

Thanks

All the best,

Mike

[Merlin66]

Olly,

It looks far more substantial than it really is....a length of 50 x 50 x 3 aluminium sq tube fixed to the ADM minirail with the clamp and a series of 35 x 35 x 3 aluminium angles bolted to the camera/ spectroscope end...next time I take it off I'll weigh it but I think no more than 350-400gms.

I set up the spectroscope square to the ATO - spirit levels and vernier (you only do this once -right? (See below!)) and then measured the required off-sets to allow me to use a 1/4" clamp bolt (ex the Skywatcher) to quickly fix and release the instrument. Measure three times and cut once!

Works 100% I can now focus the target star onto the 20micron slit and swing the scope anywhere around the sky knowing that nothing will shift.

** I've just upgraded to a C11 and had to re-measure and re-adapt the support bar - as luck would have it (no kidding!) all it took was a 18mm spacer!

I should also mention my mate Marco from Gorgonzola, Italy. He found this absolutely fantastic matt black paint - designed to touch up aluminium window frames (TALKEN Color - ANODAL: #9071, Anodizzato Nero) This stuff needs no primer when applied to aluminium and honestly (as you can see) gives a perfect result which looks like anodizing everytime. Magic stuff - highly recommended.

HTH

[MikeWilson]

I ordered an AC573 Astro Engineering par focal ring on chance that it might fit.

It's exactly 4mm thick - perfect for the TRf2008.

:-)

This will help reduce droop.

Sent from my mobile using TapaTalk (so please excuse bad grammar & spelling!) :-)

[Black Knight]

Hopefully that'll do the trick then

[MikeWilson]

Hopefully that'll do the trick then

Fingers crossed!