1"1/4 - 2" 'in line' adaptor

[Chriske]

V1.
This is a attempt to make a 'in line' adaptor.
Not only will the eyepiece be forced toward the very centre of the optical train, but also that different eyepiece diameters 'problem' is solved.
Printed in PLA, cost 0.71€
On both side there's a shallow slope, to allow smooth insertion both the adaptor itself in the focuser and also eyepiece insertion into the adaptor.

[Gina]

Very clever - love it ??

[Rusted]

How do you ensure enough compression for guaranteed grip on the 1.25" diameter?

There seem to be no other inward force than spring/flexure/resistance of the "flippers."

A heavy load could still de-center your "flippers" because it relies only on their stiffness for both alignment and parallelism.

What happens when you hang a bunch of stuff on the 1.25" diameter and then point a refractor at the zenith? Newton is very rarely wrong.

I imagine partially split cones [collet style] would center the 1.25" nicely but would still need screw applied, opposing cone, end loading to ensure a safe grip.

[Chriske]

This adapter is to be used for eyepieces only, so no heavy camera allowed in this thing.
In 99% of the situations a larger eyepiece has a 2" barrel and the smaller eyepieces have 1"1/4 barrels .
PLA btw is very stiff, still flexible enough to allow some flexing to hold these smaller eyepieces very firmly. Even in a refractor pointing at the zenit. Already tested it, made a few smaller modifs and V3 is printing right now. And no there's no way this adaptor will deform under a small eyepieces' load. Most certainly not in Winter and what's more because I printed that thing pristine white I can use it in the Summer to. Tested that also(white PLA in the sun).

I intend to print one for each of my smaller eyepieces. So every eyepiece stays with it's own adaptor.
And let's assume that after some time this adapter starts to deform(PLA does after a long time, I know) well, I'll print me a new one... It'll cost me only 0.7€ ....

These partially split cones adaptors you're mentioning, I used them for (about) 20 years now. I got the idea from a ATM guy in the US. Mike Mickels gave me permission to copy his adaptors to be used in my ATM course at our observatory. So I made my own version for our members. But it needed a threaded ring to close and grip the eyepieces. I wanted to eliminate that ring or any other means of fastening bolts/knobs. So that's why I made this 'springloaded' adaptor.
As a matter of fact I never use bolts or knobs to secure my eyepieces. All my adaptors are custom made, so all my adaptors and also all eyepieces are inserted in all my scopes with just a little bit of tension. That tension is just enough to prevent things from falling out of my scope(our coursemembers do not use these knobs either)
And no I never use refractors....pointing at the zenit...
In fact in al the telescopes I ever built, there was/is not one eyepiece pointing downward. And there's no way I ever will do that.

[Rusted]

It sounds good.

The only thing I would ensure is that the open end is capped to avoid dust infall around the EP.

I store my refractors on their dewshields in the workshop and often need an industrial vacuum cleaner to clean the sawdust off the backs of the objective lens.

Even the focuser annular clearance is enough to leak micrometeorites.

I should use individual poly bags over the focusers but they get such a bad press these days.

[Chriske]

Using most of the time Newts there's no problem with these little gaps around the 1"1/4 eyepiece. I think there's another very BIG hole that most probably will collect far more dust than these little gaps.
In my case there's no problem because I only need to clean my telescope mirrors every 10 years or so...  And I too have stored all my telescopes in my workshop the last 39 years.

On the other hand, I think you do have a problem. Never heard of cleaning the backs of lenses before. Refractors and SCT's never have to be cleaned on the inside. You only need to cover that eyepiece hole while storing.

[Rusted]

11 hours ago, Chriske said:

Using most of the time Newts there's no problem with these little gaps around the 1"1/4 eyepiece. I think there's another very BIG hole that most probably will collect far more dust than these little gaps.
In my case there's no problem because I only need to clean my telescope mirrors every 10 years or so...  And I too have stored all my telescopes in my workshop the last 39 years.

On the other hand, I think you do have a problem. Never heard of cleaning the backs of lenses before. Refractors and SCT's never have to be cleaned on the inside. You only need to cover that eyepiece hole while storing.

The problem is not the EP "hole" but the gap between the moving drawtube and focuser casting.

It was never like this in my day [last century] of push-pull RAS threaded focusing mounts!