144 replies to this topic

[Starman1]

I DID find the point I was comfortable when making my own eye guard- seemed about a quarter of a mile from the top of the eyepiece (actually about an inch).

Ridiculous!

However at that point I couldn't even take in the whole field of view.

I spent half a day experimenting. Never experienced the likes with any other eyepiece.

Well, obviously if you can't see the entire field, you are outside the exit pupil.

When you are at the exit pupil, the edge of the field should *just* be visible.

I found the eye relief from the glass 23mm and the rubber eyecup when folded down to be 20.7mm.

That is nearly 5.7mm longer than the effective eye relief of the Pentax XW eyepieces, a model of eyepiece most people use with glasses on!

So you will need an additional eyeguard extender to hold your eye 23mm from the glass or you will drift forward.

And if that doesn't work, perhaps it isn't the right eyepiece for you.

[Refractor6]

Thanks for the suggestion.

What's the FOV of the LVW?

I don't want to spend too much on an EP just for birdwatching. However the Morpheus 17.5m 76 degree specs were ideal for scanninng wide areas etc. I may just have to use the 20mm 68 instead - great EP, just less magnification.

 65 degree for the whole range from 22 down to the 3.5 Leah.......

[Refractor6]

  Here's a interesting comparison between Baader Hyperion and the Vixen LVW eps Leah by one of our members John Huntley back in 2011. The Orion badged ones also you can find on the used market are the same eps...that's the ones I got back in 2003:

 

https://www.firstlig...ion-review.html

[Princess Leah]

Well, obviously if you can't see the entire field, you are outside the exit pupil.

When you are at the exit pupil, the edge of the field should *just* be visible.

I found the eye relief from the glass 23mm and the rubber eyecup when folded down to be 20.7mm.

That is nearly 5.7mm longer than the effective eye relief of the Pentax XW eyepieces, a model of eyepiece most people use with glasses on!

So you will need an additional eyeguard extender to hold your eye 23mm from the glass or you will drift forward.

And if that doesn't work, perhaps it isn't the right eyepiece for you.

So I just tried some o-rings I got the right spot. However still plenty of black-outs in daylight. Even when not panning I can still get the odd blackout.

 

No blackouts when I'm slightly out with the entire FOV, but that's no use.

 

Ironically it works best with the eyecup completely out the way (folded down). That is how I would use it at a dark site.

[Princess Leah]

With SAEP is there a very small area of the exit pupil in the centre which is flat/usable - hence the Morpheus may work fine at a dark site?

[Princess Leah]

With SAEP is there a very small area of the exit pupil in the centre which is flat/usable - hence the Morpheus may work fine at a dark site?

Scrub that. The diagram Don references explains it perfectly.

That's exactly what I experience with my 17.5 Morpheus.

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[Starman1]

With SAEP is there a very small area of the exit pupil in the centre which is flat/usable - hence the Morpheus may work fine at a dark site?

Your pupil will be larger, which should make it easier to handle the exit pupil.

[Starman1]

Scrub that. The diagram Don references explains it perfectly.

That's exactly what I experience with my 17.5 Morpheus.

One problem with that interpretation: Richard (25585) is extremely sensitive to SAEP, yet he uses the 17.5mm Morpheus successfully and easily.

I don't see any SAEP in the eyepiece, and I can generally see it in any eyepiece that has it.  I may tolerate it, but it's never invisible to me unless the eyepiece has a very short focal length.

And SAEP is never mentioned in any review of the eyepiece.

So it is likely that you are having positional issues due to a small daylight pupil, coupled with a very long eye relief.

If that is the case, and I think it likely, nighttime use should be a lot easier, or use in a longer f/ratio telescope.

[Princess Leah]

Fingers crossed the clouds will clear.

 

Do you need a dark site for your pupils to fully dilate?

[deSitter]

Fingers crossed the clouds will clear.

 

Do you need a dark site for your pupils to fully dilate?

 

No. Dark adaptation at the iris level is almost immediate. Even in the middle of a large city at night, your pupils will dilate almost to maximum.

 

-drl

[Princess Leah]

That's what I thought, so whats the theory of the 18mm UFF mentioned previously only being comfortable at a dark site. How would a dark site influence this?

[Starman1]

That's what I thought, so what's the theory of the 18mm UFF mentioned previously only being comfortable at a dark site. How would a dark site influence this?

If I were to hazard a guess, the sensitivity of the retina might make the presence of the field stop a bit more obvious, pointing to the exact exit pupil position.

Otherwise, comfort might depend on how bright the object was you were looking at, or the eye relief of the eyepiece.

 

However, drl is not completely correct about the maximum opening of the pupil (I give him credit for saying "almost").

While it is true that the pupils dilate quickly, even in the city, your maximum pupil size does depend a bit on how bright your surroundings are.

I have a Sky & Telescope pupil gauge from many years ago, and my night pupils never exceed 3.5mm here at my home in LA. (in daylight 1-1.5mm)

At a dark site they reach >4mm (maybe 4.5mm at maximum IF I don't look at the sky), so the darker environment does cause them to open a tad farther.

I would think that factor would not be determinative on deciding whether the eyepiece was comfortable to use or not.

[Princess Leah]

Thanks for explaining.

 

I seem to remember you telling me you can read magazine print easily due to light pollution where you live! Not as bad here and my impression when I last measured was my pupils were more or less the same here as a dark site. Maybe 0.5mm difference.

 

There were some holes in the clouds last night, so I wrapped a black sheet around me and the eyepiece. As I scanned the Morpheus blinked on and off repeatedly. I tried a 40mm Plossl, no problem.

I'd be surprised if this was different at a dark site, but then again I'm often surprised with the fickle nature of optics!

 

SAEP seems to be the obvious cause, perhaps I'm more sensitive to it. Also as DeSitter rightly said, people spending premium on equipment often don't want to criticise it.  

 

Last night I switched to another EP you and Jon Isaacs recommended to me - the Founder Optics/Stella Lyra 20mm LER 80 degrees. Comfort and sharpness was off the chart in comparison.

Shame it is a 2 inch EP - but it's a joy to use.

[Princess Leah]

I'm thinking with practice I might be able to make the Morpheus work for me.

[deSitter]

I'm thinking with practice I might be able to make the Morpheus work for me.

 

Well, yeah. I feel like that about my UWAs. But I don't enjoy the view when it is so hard to come by. It's a matter of personal preference. Those who are about to drop a lot of cash of a 100 degree eyepiece should be aware of the compromises. 

 

-drl

[Princess Leah]

Agreed.

 

Although a caveat to that is I used to find eyepieces like the ES16mm/68 uncomfortable to use due to the small eye relief. Now I find the eye relief ideal and find the EP very comfortable.

[Mike B]

Agreed.

 

Although a caveat to that is I used to find eyepieces like the ES16mm/68 uncomfortable to use due to the small eye relief. Now I find the eye relief ideal and find the EP very comfortable.

Yes…. Some things just come with time, use, & practice. Since I’ve been peering thru EPs of ALL sorts since ~1970, I seem to get along fine with most- time, use, & practice- etc… So I may NOT necessarily be the best recommender of “easy-to-use” EPs?!  
 

But I think I CAN say the 17.5mm Morpheus is a splendid EP, and for me at least, checks a lotta boxes! Don’t give up too easily- keep at it with patience… when it’s exit finally clicks with your eye, you’ll be rewarded richly!

[Princess Leah]

I’ve been hoping for a few detailed comparisons between the old pseudos and the new MOPs, which might put this statement to the test, but haven’t seen anything.

I noticed light transmission is less in the15mm Parks , than an ES 14mm 62. I assume down to modern coatings.

However the Parks still seemed to reveal quite a bit more detail on a bright target (Jupiter).

 

I would expect the modern MOPs to be better in this respect?

Anyone noticed this?

Edited by Princess Leah, 29 April 2025 - 08:06 AM.

[Princess Leah]

I tried my 17.5 Morpheus at a 'relative' dark site last night at a rural location.

No problems at all.

I have no idea why that is.

 

Several people here have the same eyepiece and enjoy daytime birdwatching. Has anyone else had trouble during the day with this EP?

[Princess Leah]

Does perhaps your eye position/eye relief you require vary depending on whether your pupils are dilated or not?