Orion Q70 a tight fit!

[starboy71]

Hi All,hope you are well,i need some advice everyone...i just got the orion Q70 32mm 2 inch eyepiece the other day for my skywatcher 200p dob..excitedly tried it last night...well...its a tight fit in the extension tube where as the other 2inch EP i have(stella lyra) fits in no problem...i would like to continue leaving the extension tube in for various reasons...so has anyone out there had an issue with very tight fitting eyepieces?..i had to be quite forcefull  putting the EP in...kinda had to push n twist..any advice/suggestions to ease my worry,many thanks in advance...cheers

Mark

[Louis D]

Only ever had this issue with a Rini homemade eyepiece that used an aluminum insertion barrel.  I had to sand it down with emery cloth to get it to fit.  You shouldn't have this issue with commercially made eyepieces and extension tubes.

Does it fit in the original focuser without the extension tube?

[starboy71]

hi louis, yes it fits perfectly without the extension tube. i thought the same thing as yourself...get some emery cloth. it may only need a miniscule shaving off of it but thats a lot of rubbing!

[Louis D]

6 hours ago, starboy71 said:

hi louis, yes it fits perfectly without the extension tube. i thought the same thing as yourself...get some emery cloth. it may only need a miniscule shaving off of it but thats a lot of rubbing!

Either get a new extension tube or sand down the interior of the extension tube you already have.

[starboy71]

the extension tube has a compression ring....my other 2inch ep just drops right in  perfectly but this orion ep has a machined raised part to its tube...thats whats causing the tightness.

[Louis D]

2 hours ago, starboy71 said:

the extension tube has a compression ring....my other 2inch ep just drops right in  perfectly but this orion ep has a machined raised part to its tube...thats whats causing the tightness.

Due to the relative cheapness of extension tubes versus eyepieces, I would err toward sanding the extension tube.  I haven't read of anyone else having insertion issues with that particular eyepiece.

Have you tried removing the compression ring and using just the thumbscrew to tighten it down?

[starboy71]

oh thats a good idea i shall try that,never even entered my head to try,thanks Louis

[Ricochet]

On 22/04/2021 at 17:20, Louis D said:

Only ever had this issue with a Rini homemade eyepiece that used an aluminum insertion barrel.  I had to sand it down with emery cloth to get it to fit.  You shouldn't have this issue with commercially made eyepieces and extension tubes.

Does it fit in the original focuser without the extension tube?

This isn't a good test as I believe with the 2" adaptor removed from the focuser the remaining hole is larger than 2" so even an oversized eyepiece barrel will still fit. Careful measurement of both the 2" adaptor and eyepiece barrel is probably the best way to determine which is at fault.

[Louis D]

6 hours ago, Ricochet said:

This isn't a good test as I believe with the 2" adaptor removed from the focuser the remaining hole is larger than 2" so even an oversized eyepiece barrel will still fit. Careful measurement of both the 2" adaptor and eyepiece barrel is probably the best way to determine which is at fault.

By 2" EXTENSION tube, not adapter tube, I assumed the OP is using something similar to pictured image below to reach focus because the primary mirror is too far forward in the tube even with the 2" adapter in place:

In which case the original hole is also 2" in diameter.

If it is actually the SW 2" adapter below to which he's referring:

Then yes, it's a larger opening into which it's being inserted.  However, I don't see a compression ring in the adapter image or in any other I've found online, and the OP clearly stated it has a compression ring.

Perhaps the OP can clarify if he's referring to the OEM 2" adapter or an aftermarket 2" extension tube.

It sure would be nice if SW would switch to a GSO style Dob focuser with a native 2" opening that accepts a 1.25" adapter to avoid confusing users: