self centering eyepiece holder

[lancerde]

Not sure if I have used the correct name for these in the tread title but I would like to replace my 1.25 adapter with the type that you tighten up by twisting a knurled outer ring on the holder. It would make it easier to search if I knew the correct name or a manufacturer for them.

[Stephen]

One of these?

http://www.altairastro.com/product.php?productid=16220

[lancerde]

That must be a world record reply time. Thanks that is perfect

[John]

How do you ensure that the self centering eyepiece holder is itself centered ?

[E621Keith]

I think the OP may be after a twist lock eyepiece holder rather than a self centring holder. Baader does one, they called it click lock

http://www.firstlightoptics.com/adaptors/baader-click-lock-125-inch-eyepiece-adapter-with-t-2-thread.html

[Freddie]

Hotech also do one. FLO have them.

[Carbon]

I just ordered an Antares brand, looks identical to Orion.

[Black Knight]

I just ordered an Antares brand, looks identical to Orion.

I think they are identical.

[lancerde]

Where did you order the antares one from? Altair are out of stock until Aug.

[Bart]

I think they are identical.

I have the antares one, one of the most useful bits of kit ever, no more messing with screws with cold fingers.

Bart

[Bart]

Where did you order the antares one from? Altair are out of stock until Aug.

try agena astro in US

[Black Knight]

Where did you order the antares one from? Altair are out of stock until Aug.

Have you tried Rother Valley Optics? http://www.rothervalleyoptics.co.uk/2inch-1-25inch-twist-lock-adaptor-with-t-ring_d2911.html

[Stephen]

I think the OP may be after a twist lock eyepiece holder rather than a self centring holder. Baader does one, they called it click lock

http://www.firstligh...t-2-thread.html

That's not quite suitable I think as it's not designed to go into a 2" receptacle is it?

Hotech also do one. FLO have them.

I think the Hotech one is only suitable for centring a t-threaded camera? (It doesn't have a 1.25" receptacle?) I could be wrong.

I think they are identical.

I quite agree

[lancerde]

Thanks folks. I know where to look now.

I want one in the main for my laser collimator. Every time I check collimation then remove and replace the laser without moving the scope the dot has moved. Also no fumbling about with tiny thumb screws in the dark.

[Black Knight]

Thanks folks. I know where to look now.

I want one in the main for my laser collimator. Every time I check collimation then remove and replace the laser without moving the scope the dot has moved. Also no fumbling about with tiny thumb screws in the dark.

Yeah, they're very useful for collimation puposes. So useful in fact that the Hotech laser collimator comes with one built-in! http://www.firstlightoptics.com/collimation/hotech-sca-laser-collimator.html. 'tis expensive though .....

[Freddie]

Expensive but a great bit of kit and Stephen was right with his comment on the hotech adaptor.

[Carbon]

But also make sure that the laser collimator itself is collimated before relying on a self-centering adapter.

[brantuk]

"But also make sure that the laser collimator itself is collimated before relying on a self-centering adapter"

Yup - good advice - I would add that the SCA works best if the focuser tube is firm and squared up too

[Stu_2011]

How do you ensure that the self centering eyepiece holder is itself centered ?

Notice how no answered that, the design of these self centring collet type adapters seem a bit flawed don't they, the eyepiece centres well in the 1.25" holder but the holder doesn't naturally centre well in the focuser does it, it's always pushed to one side by clamp screw

I try and make sure that brass compression rings or clamp screws are 180 degree apart with my rationale being that you normally have two of these joints in the optical path (focuser to 2" then 2" to 1.25") so this compensates for the movement. It's not perfect but helps I think

Thanks

Sent from my iPad using Tapatalk

[brantuk]

If you get the focuser tube squared and firmed up as near as possible with the SCA in place - then do your collimation afterwards - the whole aparatus should be ready for use. You will have adjusted the optics to suit a well positioned focuser. As with everything in this hobby however - you have to spend money to get the higher quality focuser mechanics. I doubt a Moonlight focuser would have the same issue.

[John]

.... I doubt a Moonlight focuser would have the same issue.

I've recently acquired my 1st Moonlite (an older one) and it is collimatable, if required, so that you can adjust it's tilt in relation to the optical axis of the scope. I didn't actually need to as it happens - when fitted to my ED120 it was perfectly squared as evidenced by a laser beam shone though the scope exiting bang in the centre of the objective lens.

The Moonlite drawtube has 3 set screws at 180 degree spacing around the compression ring so that any accessory in there is held centrally.

[lancerde]

Surely the accessory would only be held centrally if you could ensure that each of the three screws were turned in exactly the same distance. Not sure how you would achieve that or indeed if that degree of accuracy is required?

[John]

Surely the accessory would only be held centrally if you could ensure that each of the three screws were turned in exactly the same distance. Not sure how you would achieve that or indeed if that degree of accuracy is required?

You can fine tune the positioning of an accessory using the 3 screws but not all accessories need that level of accuracy I'd agree. Having a focuser that is square with the optical axis is important though I think. When you use the laser to check it's surprising how many are not, even with refractors.

[Carbon]

Mine came in the mail yesterday. I tried it out last night running all my eyepieces through and it performed quite well. Nice, solid action. For $30 I think I will order another for my dob.

[Teslar]

They are indeed excellent bits of kit. I got one from and American eBay supplier. Cost £24 delivered. But bought a second recently from RVO as I wanted it fast