Louis D

It looks like you haven't gotten the camera lens in close enough to take in the actual field stop.  As you say, you should see a thin blue line just inside of the blackness of the actual field stop.  You may not be getting your eye in close enough, either.  Make sure you don't have the included eye cup extender on the eyepiece.  Also, make sure the eye cup is fully folded down when wearing eyeglasses.

I've not read reports of this issue with the 17.5mm Morpheus, but anything's possible.

Try to take a picture through the eyepiece during the daytime using your cell phone's wide, or better yet, ultrawide angle camera.  In my experience with slow scopes like your SCT or my Mak and an ultrawide angle phone camera, you'll get a rainbow effect if you've got true ring of fire which is actually chromatic aberration of the exit pupil (CAEP).  You can see it below in the 30mm ES-82 and 26mm Meade MWA Easy images below.

32 minutes ago, Don Pensack said:

If you're waiting for the £100 100° eyepiece, it'll never happen, but they are under €250.

Remember the Zhumell Z100 100° eyepieces in 9mm and 16mm focal lengths?  IIRC, they were closed out for around $100 each at the end of their stock run.  I'm not saying they were well corrected, but they were cheap for a bit.

I prefer rubber O-rings to parfocal rings because they won't create dimples in the insertion barrel and don't have issues with tightening on the edge of undercuts.  This is the case with my 12mm NT4 which needed 20mm worth of 4mm thick O-rings.  The last one is riding on the lower slope of the undercut.  Check ebay for O-rings.

The Meade 5000 Plossl/SWA/UWA and Celestron Axiom LX/Luminos are all famous for having bulky outer coverings that can be removed to make them lighter by about 1/3rd and slimmer.

9 hours ago, badhex said:

Perhaps it's currently just not possible to get reasonably priced, lightweight and well corrected 100° EPs - an astro version of "cheap, fast good: pick two".

Right.  Perhaps with exotic glass types and aspherical surfaces, one could achieve the latter two criteria while losing the first.

Of course, it they could sell millions of them like smart phones, the price would come down dramatically due to economies of scale.  If only 300 to 1000 iPhone 13's were made, as is the most likely case with the 26mm Meade MWA, they would be astronomically expensive (think hundreds of thousands to millions of dollars apiece to recoup R&D, wafer mask, and initial tooling expenses alone).  There just aren't enough amateur astronomers in the world to bring down the cost of exotic eyepiece production, so we'll likely never see them come to market.  Maybe some military will pay the tab for a short run of exotic eyepieces that we can then buy in 30 to 50 years time when the spares are surplussed due to obsolescence.

If you scroll down to the bottom of the posting by Ernest, he tests the 26mm Meade MWA.  Above that, he mostly rags on my report as being methodologically flawed because I use comparative analysis against my other eyepieces to arrive at photographically derived central and edge focal lengths as well as AFOV.  He never even tries to put a value on the edge radial focal length.  I take all the claimed and measured values, run a best fit mathematical analysis on the data, come up with a coefficient, and apply it across the board.  With 70+ data points (eyepieces), the fit is pretty darn good.  For the 26mm Meade MWA, central focal length is 25.1mm while the edge radial FL is 21.2mm, so not much variation.  With my method, I can even measure/calculate the easy and full AFOVs that Ernest doesn't both to measure.  They are 79.4° and 83.3°, respectively.  Thus, you don't lose all that much AFOV due to SAEP by pulling back to 18mm of eye relief to avoid 95% of it.

Ernest goes on to nitpick that the eyepiece doesn't deliver 100° AFOV, but 83.6° (really close to my measurement) instead:

Claimed to be 100 degrees with an actual angular field of view of just 84 degrees! The audacity of Meade is amazing. Even the effective field of view (across the aperture) is only 90 degrees. That is, it is never a competitor to the 25 mm 100-degree from Explore Scientific.

However, he fails to grasp that it delivers the same TFOV as the 25mm ES-100 since both have a 41mm field stop, but with distortion opposite that of the ES-100.  Both have an eAFOV of 90° based on this common FS value, so both show the same TFOV.  They're basically a true competitor, just with opposite distortion.  Thus, the Meade is saying it delivers the same TFOV experience as its competitor's product in a deceptive way by claiming 100°.

Ernest even defends the 5mm and says below his review of this distortion difference yielding the same TFOV as others' 100° eyepieces:

'MWA in this sense are more "honest" eyepieces. And attacks from some observers are explained by a misunderstanding of basic optical concepts.'

And yet he falls into the same trap with the 26mm!  He needs to be consistent in how he applies his reasoning.

I also totally don't get his results at f/7:

In a telescope 1:7

Strong defocus at the edge of the field of view due to curvature

In the zone, a clearly visible halo of curvature slightly shifted to the side of the edge of the field of view

At 50% of the zone, the images of the stars are already noticeably "snotty"

All is well in the central area

At f/6 and f/6.7 in my field flattened refractors (ED and APO, respectively), I can't detect more than the tiniest defocus center to edge, and my eyes don't focus anymore to accommodate field curvature, so I would see it, but I don't.  Also, the stars are basically pinpoint to the edge.  It's barely worse than my 22mm Nagler T4 in this respect.  His words make it sound like it has an edge performance level similar to a 26mm Orion Q70, which it most certainly does not.  In fact, it is this lack of field curvature and lack of edge astigmatism that has made it grow on me despite its warts (strong SAEP and barrel distortion).

Here's my take on the 26mm Meade MWA that no other branding seems to have ordered:

It's flawed, but it kind of grows on you.  I'm keeping mine as a rather unique eyepiece that is no longer available.  It's sort of a 25mm (it's true focal length) Morpheus with barrel distortion and SAEP.  Until Baader markets a 2" Morpheus in that range, it will have to do.

2 hours ago, badhex said:

Do we know who makes them? Might be possible to find other white labels with reviews? 

I think we can rule out KUO (Kunming United Optical) that makes the well regarded APM/Lunt/Stellarvue/Myriad/WO/Astro-Tech/etc. XWA 100 degree eyepieces.  Why would they also sell a poor, non-competitive, false 100 degree line of eyepieces?

We can probably rule out JOC/Explore Scientific/Bresser since they also have a bonafide 100 degree line of eyepieces (ES-100).

That would leave Long Perng (I doubt it having never seen these on their website) and some others.  If I had to guess, it's the same company making the Celestron Luminos and its bretheren since both are flawed interpretations of other eyepiece lines (i.e., Ethos and Naglers) with overstated eye relief figures.  However, no one seems to know who is making the Luminos line, either.

They're reviewed here in Omegon Panorama II livery:

2 minutes ago, badhex said:

Maybe you've already seen this but this thread from a few years ago talks about them:

Our good friend @Louis D mentions that they are also available branded as 'Magellan' from Kokusai Kohki:

http://kokusai-kohki.com/products/magellan.html

 

I had totally forgotten I'd posted that almost exactly 3 years ago.  Good catch!

More than likely another branding of the Meade MWA line-up:

Perhaps a 20mm XWA from APM/Lunt/Stellarvue/Astro-Tech/etc?  You might gain 5mm in field stop size.  There's always the TV 21mm Ethos as well.

7 minutes ago, doublevodka said:

I believe the top ring allows removal of the twist up piece, I seem to remember seeing that somewhere.

It'll make your wallet hurt a bit, but as you both have astigmatism it may be worth looking at this https://www.televue.com/engine/TV3b_page.asp?id=54

The problems with Dioptrx are

• It won't fit all eyepieces
• Still requires about 15mm of usable eye relief, so not a panacea for astigmatism sufferers
• Prevents view swapping unless you both have the same amount of astigmatism (you can simply adjust the angle by rotating it if it differs between observers)
• Requires one per eyepiece unless you like messing about in the dark swapping it across eyepieces
• Still leaves you blind when looking up to the sky from the eyepiece
• The correction angle changes depending on the altitude of the object when using a Dob requiring retuning between objects.

Using long eye relief eyepieces with eyeglasses pretty much eliminates these issues except that eyepiece choice becomes a bit more limited due to needing 17mm to 18mm of usable eye relief.

On 15/07/2022 at 04:39, Dave scutt said:

Just completed my first ep case.

I think I've got the fever and want to collect more, but what next

Perhaps swap the 18mm and 24mm UWAs for a 20mm XWA from APM/Lunt/Stellarvue/Astro-Tech/etc?

4 minutes ago, doublevodka said:

Grip tight with both hands and twist in opposite directions worked for me. It was tight the first time but no threadlock as far as I can see

I guess I'll have to give it a bit more effort now that I know it should go downward.

I've pulled the rubber eye cup off before.  I'll have to try using a lens spanner/wrench to undo that top ring to see if the whole assembly drops off downward.

I'm trying to make these things eyeglass friendly for me and my daughter.  The both of us have a lot of eye astigmatism.  I much prefer the Meade HD-60 line for this reason.  There's basically no eye lens recession once you flip down the rubber eye cup and fully twist down the extendable eye guard.  She's got both sets at her house right now, so uncloaking experimentation will have to wait.

I can unscrew the printed ring and then the colored beauty ring slips off, but the big upper part won't unscrew or slip either direction.

However, I was trying to get rid of the eye cup because it eats up 4mm of eye relief, causing the eyepiece to go from 16mm to 12m of ER, making it appear more like a Plossl with eyeglasses.  It appears the eye cup is still solidly attached when done with your decloaking.

Thanks for the clear photos and explanation, though.

On 19/07/2022 at 06:38, Pixies said:

If this was a nice refractor, we'd be talking sandalwood cases and Louis Vuitton bags. But it's a dob, so mucky blankets and bits of string!  

My daughter's 127 Mak is somewhere in the middle.  It's stored in a Walmart duffle bag wrapped in bubble wrap.

4 hours ago, FLO said:

It was. But it had loosened during its journey from Taiwan to UK. This is not unusual and is easily solved (a quick tweak of the focuser tension adjustment screw). 

In the OP's defense, where in the included instructions did it mention this crucial adjustment as an important check, and how to perform it if it is such a common occurrence?

As a practicing engineer of many years myself, this episode would cause our group to perform a root cause failure analysis, call for suggestions to correct it, come to a consensus on the best way forward, and then put an action plan in place to prevent recurrence.

3 hours ago, Mike Q said:

If you are wanting instructions you can go to orion's website and find the skyline 8 inch.  There should be a down load there for the manual.    To my knowledge the only difference is the name on the side of the OTA

Yep, here's the link.

Tips from Texas for solar observing in extreme heat:

• Wear a wide brimmed, ventilated hiking hat to avoid sunburn on the head while avoiding cooking your brain.
• Put a large box fan blowing on high across your body at 90 degrees to the direction of the scope.
• Wear shorts and a T-shirt or very light fabric, full covering clothes that breathe well.

I can manage about 20 to 30 minutes at noon solar observing in 95+ F heat before I need a break in the A/C to get water, cool off, and to avoid sunburning my arms and legs.  If you don't have A/C, I recommend placing cold/damp washcloths on your head to cool off your brain to avoid heatstroke.  You can keep them on your head under your hat when you go back out, at least until they warm up to ambient temperature, then remove them because they then impede evaporative cooling.  Cool/damp cloths around your neck can also help as well.

The key thing is to listen to your body.  If you start feeling woozy or lightheaded, start cooling off immediately.  Your brain does not like overheating and needs to be cooled immediately to avoid passing out.  It generally shuts down first in my experience.  Laying flat on the floor can ease the strain on your heart and allow blood to flow through your brain more easily to cool it.  If you can't get inside for whatever reason, find shade ASAP, lay down, and call for help if someone is in earshot.

6 hours ago, doublevodka said:

3 - Unscrew the bulky body of the eyepiece

This is where I got stuck by that middle section not unscrewing up or down.  Perhaps mine is theadlocked.

I just wrap my OTA in an old, thick blanket in the trunk (boot) during transport.  Seems to work fine for me.

4 hours ago, doublevodka said:

Oh and yes, I like the twist up eyecup too, although I've decloaked the eyepiece because it's just a bit to chunky for my liking

I tried with my AT Paradigms (BST Starguiders), but I couldn't get the upper metal assembly to come off.  Is the trick using a lens spanner/wrench to remove the upper ring of the twist-up eye cup?

I just have to ask why the focuser tension wasn't adjusted properly at the factory.  Have they simply given up on imparting a good customer experience out of the box?