Morpheus 4.5mm eye relief

[badhex]

Hello all, 

I really enjoy this EP and it has been coming into its own since the planets have started to show their faces, however I have always found the ER of this eyepiece to be a bit picky. 

I do not wear glasses, so I found with my Morpheus 17.5mm that I need both the M43 extension plus the eyeguard for perfect eye placement. 

With the 4.5mm, I have tried without but still definitely need the extension, but then I find that with the both the extension and eyeguard, I can't see the full FOV and fieldstop unless I push my eye into the EP which is not good for high powers and  manual push mounts like the mount zero. With the extension and eyeguard in place but rolled down, I can see the full field, but I have to float a few mm above the eye cup and end up getting blackouts half the time. Seems like I need the eyeguard to be rolled halfway down for perfect placement, which is not possible. 

Short of buying a new eyeguard and attempting to cut it down slightly I'm not sure what I can do. I have also looked for an M43 extension that is shorter but not had any luck. 

Does anyone else have this issue? Any ideas about what I can do?

 

 

[Don Pensack]

yes, add a second extension (they are available from Baader), or, simply unscrew both the extension and the eyecup a mm or so and leave them that way.

There is no risk of them falling off because the threads are quite long, and you can dial in the extension you need.  if you are concerned about the looseness, maybe add a drop of green loctite

to the threads so they can still be threaded with a bit of resistance.

[Louis D]

You could also put an elastic band of some sort around the lower threads to screw the extension/eyecup down onto.  The friction should resist unscrewing upward.

[badhex]

55 minutes ago, Don Pensack said:

yes, add a second extension (they are available from Baader), or, simply unscrew both the extension and the eyecup a mm or so and leave them that way.

There is no risk of them falling off because the threads are quite long, and you can dial in the extension you need.  if you are concerned about the looseness, maybe add a drop of green loctite

to the threads so they can still be threaded with a bit of resistance.

Thanks Don, I suspect that a second extension will be too much, as it seems to be about the same optical length as the difference between the eyecup rolled up and Dow. I did have a play around earlier today and tried that, but not whilst looking through the scope. It did feel a bit loose, but I'm going to give it a go next time I'm out to see exactly how much spacing I actually need. 

[badhex]

18 minutes ago, Louis D said:

You could also put an elastic band of some sort around the lower threads to screw the extension/eyecup down onto.  The friction should resist unscrewing upward.

Cheers Louis, also something I thought about today! My partner has these hair bobbles/ties made of a silicone type rubber which might be the right spacing, available in black as well - I asked if I could steal one but all the ones she currently has are too big to go around the thread without dropping off. Again I'm going to try and track down a rubber band of the right size and go from there. 

[globular]

4 minutes ago, badhex said:

rubber band

Search for 'Rubber O Ring'. They come in every imaginable diameter and thickness.

[badhex]

17 minutes ago, globular said:

Search for 'Rubber O Ring'. They come in every imaginable diameter and thickness.

Cheers Glob, why didn't I think of that? 😂

[globular]

1 minute ago, badhex said:

Cheers Glob, why didn't I think of that? 😂

I could tell you needed a nudge in the right direction. 😂
(Although Don and Louis did all the heavy lifting.)

[badhex]

Quick update, I realised that this thread and another thread I started are quite similar, whoops! Other thread is a bit broader in scope, so will continue the conversation there.