MaxVision/Meade 24mm 68° 1.25" alternatives

[badhex]

Hello all

Following up on a recent topic about least favourite EPs, I have found myself idly wondering if there are any better alternatives to my MaxVision 24mm 68°. 

The large eye lens of the Morpheus (I think it's ~35mm) and Pentax XW etc. are very pleasing, and the MaxVision does tend to feel a bit too snug in comparison so a large eye lens is the first of my criteria. Secondly, it would need to work in 1.25" form factor. 

I've had a cursory dig around for different options but eye lens measurements are a bit thin on the ground, it seems. 

Edited April 26, 2022 by badhex

[Louis D]

The APM UFF 24mm and it's optical identical brethren under other brandings has enough usable eye relief (17mm) to use with eyeglasses and is well corrected across the field.  The last 5% has some vignetting issues resulting in a somewhat soft field stop due to the design being pushed a bit far (a 27.3mm to 27.5mm field stop in a 1.25" barrel, depending on where you declare the edge to be).  The eye lens is 37mm in diameter, but it's recessed quite a bit to avoid having too much usable eye relief.  It views a bit tighter than the 9mm and 14mm Morpheus and the 3.5mm, 5.2mm, 7mm, and 14mm Pentax XL/XWs all of which have 18mm to 20mm of usable eye relief.  It's enough I can't hover but must instead lightly touch my eyeglasses to the folded down eye cup of the APM.  It views the same as the 12mm and 17mm ES-92s in that respect for reference.  The APM's 63° AFOV has way less edge distortion (about 15% extra radial magnification) compared to the MaxVision/Meade 5000 SWA/ES-68/Panoptic style edge distortion (43% to 47% extra radial magnification).  I actually prefer the APM's presentation despite it appearing narrower in AFOV.  In fact, it's eAFOV (effective AFOV for accurately using the TFOV=AFOV/Mag equation) is 66° which is basically the same as the Panoptic and its variants.

It's really the only option out there at 24mm with that sort of eye relief at 66° eAFOV in a 1.25" barrel.

Here's an image comparing various eyepieces in my collection around 24mm taken through a field flattened f/6 72ED refractor for reference:

[badhex]

6 hours ago, Louis D said:

The APM UFF 24mm and it's optical identical brethren under other brandings has enough usable eye relief (17mm) to use with eyeglasses and is well corrected across the field.  The last 5% has some vignetting issues resulting in a somewhat soft field stop due to the design being pushed a bit far (a 27.3mm to 27.5mm field stop in a 1.25" barrel, depending on where you declare the edge to be).  The eye lens is 37mm in diameter, but it's recessed quite a bit to avoid having too much usable eye relief.  It views a bit tighter than the 9mm and 14mm Morpheus and the 3.5mm, 5.2mm, 7mm, and 14mm Pentax XL/XWs all of which have 18mm to 20mm of usable eye relief.  It's enough I can't hover but must instead lightly touch my eyeglasses to the folded down eye cup of the APM.  It views the same as the 12mm and 17mm ES-92s in that respect for reference.  The APM's 63° AFOV has way less edge distortion (about 15% extra radial magnification) compared to the MaxVision/Meade 5000 SWA/ES-68/Panoptic style edge distortion (43% to 47% extra radial magnification).  I actually prefer the APM's presentation despite it appearing narrower in AFOV.  In fact, it's eAFOV (effective AFOV for accurately using the TFOV=AFOV/Mag equation) is 66° which is basically the same as the Panoptic and its variants.

It's really the only option out there at 24mm with that sort of eye relief at 66° eAFOV in a 1.25" barrel.

Here's an image comparing various eyepieces in my collection around 24mm taken through a field flattened f/6 72ED refractor for reference:

Thanks for the detail and photos Louis. I had actually been searching for your series of incredibly useful posts with these photos which I've used for reference a number of times, but I couldn't seem to find them. I'll have a look at the APM and optical cousins. 

I am surprised how much distortion the Panoptic has actually. I have been on a very slow sort of quest to eventually replace some of my older stuff like my MaxVision with "EPs for life" as it were. A 24mm Panoptic might have been on the cards eventually if the eye lens is a decent size (I don't know if it is) but looking at the 27mm's distortion I'm less than convinced, even though it presumably must be a different design. Am I right in thinking that the original Meade/MaxVision SWA and UWA were copies, if not clones, of the Televues? 

[Louis D]

3 hours ago, badhex said:

Thanks for the detail and photos Louis. I had actually been searching for your series of incredibly useful posts with these photos which I've used for reference a number of times, but I couldn't seem to find them. I'll have a look at the APM and optical cousins. 

I am surprised how much distortion the Panoptic has actually. I have been on a very slow sort of quest to eventually replace some of my older stuff like my MaxVision with "EPs for life" as it were. A 24mm Panoptic might have been on the cards eventually if the eye lens is a decent size (I don't know if it is) but looking at the 27mm's distortion I'm less than convinced, even though it presumably must be a different design. Am I right in thinking that the original Meade/MaxVision SWA and UWA were copies, if not clones, of the Televues? 

My eyepiece images thread.

I've read that the 24mm and 41mm Panoptics were the last to be introduced and that Ethos/Delos/Delite designer Paul Dellechiaie tweaked the design to improve it a bit.  This had the side effect of reducing both the physical size and eye relief of at least the 24mm version to make it binoviewer friendly.  As such, it has 15mm of design eye relief, which probably equates to about 12mm of usable eye relief at most.

For reference, my 27mm Panoptic is spec'ed at 19mm ER, but I've measured mine to have only 14mm of usable ER.  It is so tight to use with eyeglasses that I've scratched an eyeglass lens on the eye lens retaining ring.  I've calculated that it can have no more than 18mm of design eye relief given its 25mm eye lens diameter.  I'm guessing the eye lens has at least 1mm of concavity to bring it up to 19mm ER.  I've since replaced it with the 30mm APM UFF in my A-Team case which is easily used with eyeglasses.  The Panoptic might be a tad bit sharper in the center, but it has a bit of field curvature and edge astigmatism/chromatism.  The APM is flat of field and has no edge aberrations that I can detect.

The Meade 5000 SWA/ES-68/MaxVision SWA eyepieces are pretty clearly Panoptic clones.  Al's patent (US4525035) expired before they were introduced (Jan 5, 2004), so it was completely above board to do so.  I think the clones use lower cost glass types to keep costs down relative to Panoptics because their correction isn't quite up to Tele Vue standards in fast scopes.

[badhex]

5 hours ago, Louis D said:

My eyepiece images thread.

I've read that the 24mm and 41mm Panoptics were the last to be introduced and that Ethos/Delos/Delite designer Paul Dellechiaie tweaked the design to improve it a bit.  This had the side effect of reducing both the physical size and eye relief of at least the 24mm version to make it binoviewer friendly.  As such, it has 15mm of design eye relief, which probably equates to about 12mm of usable eye relief at most.

For reference, my 27mm Panoptic is spec'ed at 19mm ER, but I've measured mine to have only 14mm of usable ER.  It is so tight to use with eyeglasses that I've scratched an eyeglass lens on the eye lens retaining ring.  I've calculated that it can have no more than 18mm of design eye relief given its 25mm eye lens diameter.  I'm guessing the eye lens has at least 1mm of concavity to bring it up to 19mm ER.  I've since replaced it with the 30mm APM UFF in my A-Team case which is easily used with eyeglasses.  The Panoptic might be a tad bit sharper in the center, but it has a bit of field curvature and edge astigmatism/chromatism.  The APM is flat of field and has no edge aberrations that I can detect.

The Meade 5000 SWA/ES-68/MaxVision SWA eyepieces are pretty clearly Panoptic clones.  Al's patent (US4525035) expired before they were introduced (Jan 5, 2004), so it was completely above board to do so.  I think the clones use lower cost glass types to keep costs down relative to Panoptics because their correction isn't quite up to Tele Vue standards in fast scopes.

Thanks for the link! Will keep that one bookmarked. 

As well as your helpful input I've been reading up a bit on the few EPs in the max 1.25" field category and on overall performance it sounds like there's not huge amounts in it, each having their pros and cons; "swings and roundabouts" as us Brits would say.

The biggest attraction for me of the APM and cousins is the large eye lens, and I can probably forgive the possibly indistinct fieldstop in trade. Of the few in that class it's also one of the least expensive which is another plus! 

[Don Pensack]

Plus, it's cheaper than the Orion, Meade, Celestron, et.al.

At least it is in the US, so I imagine it might be there as well.

I don't know how it compares to the Altair Astro version for UK customers.

[badhex]

15 hours ago, Don Pensack said:

Plus, it's cheaper than the Orion, Meade, Celestron, et.al.

At least it is in the US, so I imagine it might be there as well.

I don't know how it compares to the Altair Astro version for UK customers.

Well, the irony is that I'm normally based in Germany so availability of APM stuff should be easy, but at the very moment I have decided to try and pick one up I'm actually in the UK for some weeks, so the APMs are a bit thin on the ground!

I'm not really a fan of the green Altair version, and the Celestron is inexplicably and significantly more expensive than the APM, but after some searching I've managed to get the APM at a decent price. 

I actually very nearly snagged the Celestron version from a UK supplier at an even better price than the APM, but it turned out to be an old stock price (and, was no longer in stock anyway). 

[Louis D]

Let us know how you get on with it once you receive it and have a chance to look through it.

[badhex]

Definitely. I don't have the MaxVision with me right now for a direct comparison and I only have access to a tiny Celestron Travelscope, but I'm hoping it will work out nicely even in that, if the weather allows!

It should give me 3.96 deg of TFOV at 17x and the skies here should be dark enough for decent contrast hopefully. 

[badhex]

Ordered and delivered within 24hrs!