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1.25" Pushfit Adapter for SDL and HDF eyepieces? (1 Viewer)

pete_gamby

Birds? What Birds?!
I've been in email discussion with one of the members here on BF about the possibility of producing an adapter that would allow the Opticron SDL and HDF zoom eyepieces to be used on scopes that accept 1.25"/31.7mm push fit eyepieces.

We have a manufacturer in the UK that can produce this type of item for us in relatively small quantities and at a reasonable cost.

I'd like to gauge what interest there would be in such an adapter if the price to buy was around £25, possibly as high as £30?

Please let me know if you would be interested to buy (either here or by PM) and also if you have any comments or questions.

Cheers, Pete
 
I've done quite bit of playing around over the last few months with Opticron eps, and they do work well in the Pentax scopes I have. The SDL zoom would be an excellent choice for someone wanting a high quality zoom with a 1.25" fitting. It's a high quality weatherproof zoom and made in Japan. Despite what you might think, there are not many of these about with a 1.25" fitting. Would people pay £25/£30? I don't know, it's a lot of money for a piece tube. The best thing Opticron could do is to make their next scopes 1.25" fitting and make adaptors for their eps, then all the old eps could be used on the new scopes.

At the moment I'm using a Baader zoom, this has to have a slight modification to work in the Pentax so it will focus to infinity, and it works well. However, it's build quality, in no where near as good as the Opticron and it's not weather proof. I have a feeling it won't be long before specks of dust start showing inside.

I was looking to replace the Baader but there is no choice if you want a weatherproof zoom. There is the Pentax zoom, which is £350, the SDL with the adaptor would be about £280.
 
One question in return: should you repeat this question in the sections for the other brands? Your target audience is mostly people who does not already have an opticron scope body. (and apollogies if you already did)

Niels
 
I don't want people to feel I'm spamming the forums really Niels but it probably makes sense to put a link to this thread in a couple of places.

We sort of expect that existing owners of SDL and HDF eyepieces might want to try using their eyepiece with astronomy scopes.

Cheers, Pete
 
Hi Pete,

I might indeed be interested in such an adapter to try the SDLv2 in my astro scopes - there might be a Baader zoom on the market then...

If it comes to focus in Pentax bodies, it might also be an option there as the Baader one doesn't and most other astro zooms are not great.

I would not expect a huge rush of astro scope only users to buy the adapter and EP though, since these are mostly quite prejudiced regarding zoom EPs and also most will regard the quite narrow afov on the low mag end as a major turnoff.
If I see people raving about zoom EPs in astro forums it is about the latest 2x zooms on some alpha scopes offering 60-80 degree afov.

Btw. since Nikon Fieldscope EPs seem to get kinda rare nowadays, I could image that a lot of Fieldscope owners would be quite happy if there was an easy adaption for your zooms and fixed mag EPs to old Fieldscopes...

PS: Where could I get some measurements of the 40860 as I'm looking for a 70x alternative for my Kowa - I'm specifically interested in the threading diameter and pitch and diameter and length of the barrel below the threading?

Regards,

Joachim
 
Joachim - thanks for the feedback. So a Swaro 25-50x to 1.25" adapter might be a good bet :)

The thread on the 40860 (and all other Opticron eyepieces with an male thread connection) is 29x0.75-6H. Don't have the dimensions you need to hand but will post them up shortly.

The thread on a Fieldscope is internal and about 32mm diameter (maybe 30mm) AFAIK so I think it would be tricky to get the fixed mag eyepieces to work. Should be possible to make a "step out and up" adaptor ring for the zooms. If I get my hands on a Fieldscope, we can test whether they can reach focus.

Cheers, Pete
 
The Opticron SDL will focus to infinity in the Pentax, I made a sleeve for the SDL zoom out of a plastic fuel filter. but you could just wrap tape around it if you wanted. I seem to have got this the wrong way round though, I thought the idea was to make the Opticron zooms available for spotting scopes with an astro fitting.
Like I said in a previous post, there aren't many high quality zooms available for the 1.25" fitting, that are weatherproof.
 
Hi Pete,

thanks for the thread size and looking up the other dimensions - sounds promising so far.

The Nikon EPs seem to use an M32-0.8 thread... at least that's what BF member mayoayo used for his adapter:

http://www.birdforum.net/showthread.php?t=260667

With just 1.5mm on each side a metal adapter sounds indeed difficult but McGuyver style with some tape or rubber sounds possible...

Joachim
 
Hi,

BF user Crake Dude is currently selling an FS 82ED and an SDLv2 - I have asked him if he hat tried them or maybe he still can do... let's hope he looks into the thread and posts here...

Joachim
 
Joachim - the dimensions for the 40860 eyepiece that you needed are as follows:

Extension below male thread 19mm
External diameter of field lens housing 25mm

I am going to ask our supplier to make a 1.25" push fit adapter prototype that will accept both the internally threaded eyepieces (HDF and SDL zooms) and the externally threaded, fixed mag eyepieces (40809, 40810, 40858, 40860, 40861 etc).

We are taking delivery of a Nikon fieldscope early next week so we can test with that too.

Thanks to all for your input so far.

Cheers, Pete
 
Hello Joachim,

My scope for sale is the earlier Nikon ED78 not the current ED82. I don't know if the eyepiece aperture on the body of the ED82 is different internally but I have just tried to offer my Opticron SDLv2 into the ED78 eyepiece aperture but there in an internal narrower guide shelf on the Nikon which reduces the the diameter, this is about 24mm diameter which allows the nose of Nikon eyepieces to go deeper, but prevents the SDLv2 eyepiece nose, which is 27.5mm diameter, to go deep enough....so, infinity focus is out on the SDLv2.

I still think, though, an astro adapter ought to be available to fit Opticron eyepieces to 1.25" and/or 2" astronomy telescopes. I doubt if there would be an issue about the Opticron eyepieces coming to focus on infinity because of the longer focus movement back and forth, usually rack&pinion(?), on astro scopes. That's the problem with our smaller spotting scopes, that lack of length to allow this focus movement.

Also, and not meant to be a criticism to Pete, the cost of spotting scope eyepieces is far more than even mid-range fixed-power astro eyepieces of equal quality, so I don't know if astro enthusiasts would fork out the comparative extra cost for them, plus the adapter. I do realise how more expensive it must be to make the eyepieces which fit on the squatter spotting scopes compared to how much cheaper it must be to design eyepieces for longer astro scopes. It would be interesting to know how popular those Pentax eyepieces, with 1.25" fitting, are with astro users. Nikon even make eyepieces with that astro fitting too.....very, very expensive though!

Steve
 
As Steve mentioned about the aperture on the Nikon prevents the SDL and HDF from acheiving infinity focus so that project is a no go.

We'll go ahead and get a prototype made for the 1.25" push fit adapter and keep you updated on progress.

Cheers, Pete
 
Pete,

Will the SDLv2 fit the Celestron Regal M2 80ED and Pentax PR-80 EDA with your adapter and focus to infinity?

Anders
 
The first small batch of these adapters arrived this morning (thanks to John at J-Tech Design).

Checking this morning on terrestrial targets suggests that they work but I could use a volunteer to do some "real world" tests. If anyone is interested to get their hands on one (preferably UK-based to keep postage costs down), please PM me with contact details, address and what scope(s) you have to test the adapter. If necessary I can also loan one or more of our eyepieces.

It looks like the price will be £20 if we do start selling them.

Thanks, Pete
 
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