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Baader zoom alternative to Opticron zoom…. (1 Viewer)

wllmspd

Well-known member
Following some posts about Baader providing adapters for its 8-24mm click zoom mark IV to other scopes (including Opticron) I obtained a 60mm MM4 ED for use as a more portable option the heavy Astro refractor I have been using.

To adapt the eyepiece you unscrew the locking ring on the bottom of the eyepiece and replace the 1.25” adapter part with a different plate and separately available 41.5mm thread adapter, then resecure the big locking ring. You do need to remove the “dust sleeve” over the bottom part of the zoom, which just slides off, leaving about a 28.2mm diameter barrel.

On poking it into the Mm4 eyepiece hole it goes in nicely about 6mm and no further. It appears the upper threaded section is a tiny bit wider than the lower smooth section of the eyepiece hole (about 27.9mm diameter).. we’re taking 200micron or so difference. It appears that Baader must have assumed very slightly wrong dimensions for the Opticron eyepiece fitting!
I’m slightly annoyed as the Baader provides a wider field of view and is a well regarded Astro zoom, which I use on other Astro scopes I have.

So either I get the sand paper out to remove 200um from scope or eyepiece… which I don’t fancy or I need to buy an Opticron zoom, which I’d not budgeted for :-(

Thanks

Peter
 

Ratal

Well-known member
I read it as the Baader eyepiece sits inside an adapter, and this outer adapter is 2 microns too wide? If that is so, get sanding.
 

wllmspd

Well-known member
About 200microns too wide or the hole 200microns to small…. My concern is where all the metal dust will end up…. Pretty sure it won’t be magnetic, so hard to contain where it goes :-(

Peter
 

Ratal

Well-known member
Oil is your friend here. Like a whetstone and oil for sharpening a steel blade. The metal stays in the oil with nothing going all over the place.
 

wllmspd

Well-known member
They’d have to make the mark IV slightly thinner, the adapter ring is fine.
Oil is an option, but it just move the problem around and can get into more places… making clean up likely impossible. A large and a very careful operator might be an option, but it’ll be an interrupted cut which is always fun.

Peter
 

Mike C

Emeritus President at Burnage Rugby Club
England
Sounds like you have bought a Citroen as your daily driver but want to adapt Volkswagen brakes and replace the OEM parts and hope everything works - never heard of Baader but it/they must be exceptIonal…….
 

jring

Well-known member
Hi Peter,

interesting findings here... let me throw some thoughts of mine into the discussion:

- I think the Baader M41.5x1 adapter for the Mk4 zoom was originally conceived for Kowa small body scopes... So Opticron (which uses the same thread as we know from our experiments with Opticron EPs on Kowa small bodies) might work too but I am quite sure they did try each Opticron body if at all.

- not sure if the adapter shown by Pete will do the trick here... of course we would need one which has M41.5x1 female to M41.5x1 male - so essentially a threaded spacer. Even if that is the case for the adapter shown above, I would, before trying sth like that, try to hold the zoom in front of the scope as far as it goes in and see if I can get to infinity focus.

- if you want to try to rework your Opticron body to take the Baader zoom by sanding, you should first check if the EP receptacle in the body is sealed or not (i would assume sealed since the MM4 series are nitrogen filled). In that case, any metal dust from sanding can not enter the scope and thus can be removed with a vacuum cleaner.
Also check with a caliper that the EP receptacle is really deep enough to take the Mk4 nozzle.
Make sure to put a fitting round piece of painters take on the protective glass at the end of the EP receptacle - better some fiddling to get that in place and out later than a scratched glass.

Joachim
 

wllmspd

Well-known member
It would need several spacers and the far focus is only about 30m. Looks like Baader didn’t check enough scopes or maybe the Opticron eyepiece tubes are slightly different dimensions. I think the Baader is easier to sand, though a way to vacuum up the debris generated would be useful to stop bits getting into the mechanism.

Peter
 

SalmonBosha

Registered User
United Kingdom
It would need several spacers and the far focus is only about 30m. Looks like Baader didn’t check enough scopes or maybe the Opticron eyepiece tubes are slightly different dimensions. I think the Baader is easier to sand, though a way to vacuum up the debris generated would be useful to stop bits getting into the mechanism.

Peter
Did you manage to find a solution in the end, Peter?

Simon
 

wllmspd

Well-known member
Not yet. Opticron offered to open up the eyepiece end a bit, but the size issue is with the Baader part. I need to get brave and sand the eyepiece down a bit.

Peter
 

Brummie

Well-known member
Not yet. Opticron offered to open up the eyepiece end a bit, but the size issue is with the Baader part. I need to get brave and sand the eyepiece down a bit.

Peter
How would you sand it? I needed to slightly sand down some screw heads recently, and the way I managed to do it was to spin them with a rotary tool against a belt-sander that was running in the opposite direction. Trying to evenly sand something round free-hand would be a nightmare.
 

wllmspd

Well-known member
I only have a very small amount to remove… so just care and sandpaper with regular fit trials. I think I need to mod a hoover attachment to collect all the debris so it can’t go places it shouldn’t.

Peter
 

SalmonBosha

Registered User
United Kingdom
I only have a very small amount to remove… so just care and sandpaper with regular fit trials. I think I need to mod a hoover attachment to collect all the debris so it can’t go places it shouldn’t.

Peter
Best of luck if you do end up giving it a go! My only complaint about my MM4 77 + SDL V3 combo is that I find the CA at higher mags distracting in certain circumstances. I've read the Hyperion controls CA well, and I liked the view when I tried to fit one in my scope (without luck, as with you), so it's a shame about the clearance issue.

Simon
 

wllmspd

Well-known member
Started some careful sanding, but I’m concerned about getting metal dust in the zoom mechanism. Been careful to keep the tracks clear, but the zoom seems a little “grindy”, so I’m going to have a think. Maybe temporarily fill the zoom tracks, maybe use a rougher sander so the debris is larger and the metal will come off faster. I’m not rushing.
I agree about the CA in the SDL3, I was slightly surprised when I saw it, compared to what I am used to.

Peter
 

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