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1.25" self-centring eyepiece adapter


sunshine185

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  • 2 months later...

OK, this is "DP's dumb question #468":

How exactly does it fit on the scope? Does it go in the e/p holder I currently have and so because that stays screwed in one position doesn't change as I alter eyepieces/cameras? or does it have to replace my current eph/diagonal, putting the eyepiece in a nigh on impossible position to view anything unless it is very low down?

Looks like a brilliant concept (I am always centering what I want to image in the eyepiece and then finding it isn't on the camera sensor), it's just my unmechanical mind can't quite get itself around how it actually works in practice.

Thanks.

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  • 2 weeks later...

Sorry if I am being a bit thick here guys... What does "centering adapter" mean exactly? Surely, when I put a EP into my focuser it is already centered?

If I use a laser collimator for Newts, are these 1.25 or 2" devices? if 1.25 then you need to insert into a 2>1.25 stepdown adapter right? So then the question would be is the stepdown adapter centered?

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claim is the centering adapter closes in on all sides like a clamp when tightening the e/p into the focuser. where as thumb screws can push the barrel to one side or angle it .there are arguments for and against its accuracy over traditional thumbscrews. the reason i used one was it wont mark your barrel like thumb screws some times do and its easier swapping over e/p's ,at least i think so. ( and they look nice :grin: )

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the main argument against is the fact that you tighten the adapter with a thumb screw in the first place, so can you be sure that the adapter is central ?

i wasnt to fussed, i liked the idea of twist lock rather than thumb screws on a cold night .

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  • 5 weeks later...

post-21341-135818270709_thumb.jpg

Don't know if that helps?

depending on your focuser travel you can stitch it straight on or on after the 2" adaptor

The web reveals that many AP enthusiasts, particularly, are unhappy with the focusing setup that came with their scopes. Self-centring eyepiece holder/adapters are available at a price of £20 but they are not a complete answer. In my setup for AP there is potentially unrestrained slop with the extending Crayford tube, the extension tube within that, the 2” to 1.25” adapter with that, the barlow within that and the webcam or eyepiece within that.

That is 5 bits of slop, needing 5 self-centring solutions, ideally. How big is a webcam chip?

Adjusting screws are a moderately good solution if there are two per junction – that means 10 – and they would all need to be lined up in rows. The story could go on ...

Mike

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  • 11 months later...

Hi all

I realise this thread is a year old but I was looking at the Revelation 2" to 1.25" adapter and was wondering if anyone has it's above-focuser depth dimensions. I'm thinking in terms of it's effect on back focus as it's not described as low-profile. It seems hard to find an actual low-profile version of a 2" to 1.25" adapter that's in stock.

Thanks

Louise

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depends how you fit it ... it can go straight on the scope / or after the 2" EP holder. Without the 1.25" ep holder its shorter than the original, with the 2" holder its longer ! 

Well the idea is to use an adapter to fit the 2" Crayford on my 150pds in order to connect my 1100d via a 1.25" adapter with a view to using 1.25" filters rather than expensive 2" ones. There isn't much back focus with the camera attached via the 2" to T-adapter supplied with the scope/focuser. The focuser currently only has only about (you guessed it) 11mm showing... Maybe it'll be ok but I don't want to waste £20! A low-profile adapter would be fine if I could get one. I'm sure other dslr users must have come across this problem and maybe solved it!

Louise

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