A Very Unscientific 10mm Shootout

[badhex]

1 hour ago, John said:

I reckon this is the same eyepiece as the 30mm UFF but under different branding:

U.K. Astronomy Buy & Sell (astrobuysell.com)

UF 30mm Ultra Flat Field Eyepiece – Sky Rover Optics

If it is not exactly the same then it is very, very similar.

 

Cheers John, yes as Don said it's the same. Will keep an eye on the ad and see if it's still available once I'm in position to release the funds! 

[bosun21]

3 hours ago, Louis D said:

If you don't need the money from the sale of eyepieces, have the space to store them, and enjoy comparing them once in a while; then by all means keep them all with a clear conscience.  Do what's right for you.

Here's my 9mm to 10mm collection.  Curiously, I only have one 10mm eyepiece. 

Just above that at 12mm to 12.5mm is where the pile-up occurs in my eyepiece collection:

Clearly, some are very specialized eyepieces at this focal length.

The 9mm Morpheus is a handsome eyepiece and optically great as well.

[John]

1 minute ago, bosun21 said:

The 9mm Morpheus is a handsome eyepiece and optically great as well.

I've been quite tempted to get one to try out in that slot. It seems daft that I've still not used a Morpheus after reading so much about them 🙂

 

[bosun21]

5 minutes ago, John said:

I've been quite tempted to get one to try out in that slot. It seems daft that I've still not used a Morpheus after reading so much about them 🙂

 

PM me if you want to borrow one to try out for yourself. Just let me know which one.

Edited September 8, 2023 by bosun21
Typo

[MalcolmM]

1 hour ago, John said:

I've been quite tempted to get one to try out in that slot. It seems daft that I've still not used a Morpheus after reading so much about them 🙂

 

I've never tried one either. I'm just not drawn to them, which is a bit strange given the universally excellent reviews they receive! 

Malcolm 

[Don Pensack]

3 hours ago, John said:

Are they responsible for the Svbony 3-8mm zoom ?

There is a certain resemblance.

I don't know, and the eyepiece has not appeared under other brand labels.

Maybe someone else has seen the eyepiece in China or on AliExpress from someone else?

 

[IB20]

1 hour ago, MalcolmM said:

I've never tried one either. I'm just not drawn to them, which is a bit strange given the universally excellent reviews they receive! 

Malcolm 

I love the 17.5mm but weirdly don’t feel the need for any others. I’m more interested in trying a TPL.
However if there was an 8mm Morpheus, I’d get it!

[JeremyS]

6 hours ago, Louis D said:

If you don't need the money from the sale of eyepieces, have the space to store them, and enjoy comparing them once in a while; then by all means keep them all with a clear conscience.  Do what's right for you.

Here's my 9mm to 10mm collection.  Curiously, I only have one 10mm eyepiece. 

Just above that at 12mm to 12.5mm is where the pile-up occurs in my eyepiece collection:

Clearly, some are very specialized eyepieces at this focal length.

C’mon Louis. You’re not even trying 

🤣

[badhex]

I was already kicking myself that I didn't put a BCO in my travel kit and now I'm kicking myself even more after reading this! 

[F15Rules]

Nice comparison Malcolm👍.

I agree with your assessment of the TAO..I have a 12.5mm pair for binoviewing, but whether in single or double use, they are remarkable..

Key pluses:

-Contrast, inky black background

- very tight, sharp stellar images

- a subjective point  but the Tak Abbes just feel "right"..comfortable, despite typical ortho tightish eye relief, immersive, despite a relatively narrow FOV - the fov draws you into the object being observed, not the surrounding field.

- minimalist, light, simple and exemplary build quality

Minuses

- non for me, although I can see that wide angle fans might find them a bit claustrophobic 🙂

I personally really like the Pentaxs. I currently have a 10.5mm XL and an XL 8-24mm zoom, both excellent.

I'm also a fan of the Morpheus range, and found the 9mm and 17.5mm to be my favourites.

Dave

 

[MalcolmM]

25 minutes ago, F15Rules said:

XL 8-24mm zoom, both excellen

I've eyed this zoom a number of times. It looks great and would, I think, be perfect for a Mewlon. My reservations though are it's size and weight, and the small FOV at the 24mm setting. It's quite a bit heavier than the 5mm XW which I find to be bigger and heavier than I ideally like. That being said, I often use the Masuyama 32mm in the Mewlon for deep sky and it's approaching the weight of the Pentax zoom! 

Malcolm 

[John]

3 hours ago, JeremyS said:

C’mon Louis. You’re not even trying 

🤣

He is doing better than I am - I don't have any fixed FL eyepieces between 12mm and 8mm currently 🙄

Edited September 8, 2023 by John

[Louis D]

3 hours ago, JeremyS said:

C’mon Louis. You’re not even trying 

🤣

I'm really slacking off at 10mm and especially 11mm (none). 😊

[Don Pensack]

4 hours ago, IB20 said:

I love the 17.5mm but weirdly don’t feel the need for any others. I’m more interested in trying a TPL.
However if there was an 8mm Morpheus, I’d get it!

Understood, but that's unlikely to ever happen.

4.5mm, increased by 40% is ~6.5mm.

6.5mm becomes 9mm

9mm becomes 12.5mm.

And 12.5mm becomes 17.5mm.

So there was a rationale for the focal lengths.

Pentax XWs follow the same % progression, but start smaller: 3.5mm, 5mm, 7mm, 10mm, 14mm, 20mm

 

Whence comes the 14mm, then?  Well, in the original internal design, it looks like 14mm was about the longest focal length that could be made, so we got a 14mm to complete the set.

But, 3 years+ later, the 17.5mm came out, after some unsuccessful prototypes.  I think it is different internally to the other focal lengths, which is one reason it has a slightly narrower apparent field (72° versus 78-79°)

The first 17.5mm prototype (maybe the design on paper before the prototypes), which didn't work, is the data in Baader's spec chart.  They never updated the chart when the final version came out.

If you read Ernest Maratovich's charts and reviews, you'll also see they actually missed the exact focal lengths as well.

He measured: 17.2mm, 13.9mm, 12.4mm, 8.9mm, 6.7mm, and 4.8mm.

This is far from the only line of eyepieces where all the focal lengths are off, and some other eyepieces are in error by more than 0.5mm.

If we start measuring actual focal lengths and apparent fields, though, the market becomes filled with chaos and lots of exotic focal lengths.

How much does it matter in the field if your 13mm 100° eyepiece is actually 13.3mm and 101°?  It really doesn't.

 

[Roy Challen]

Hooray for the BCO! I really like all of this range, and when price is taken into account, they are super value. They also barlow extremely well with the q-turret barlow (and others). I don't find the eye relief to be problematic, even the 6mm is easier to use than the Meade 7mm RGO (which I've had two of).

I had a 0.965" Tak MC ortho some years back, I was somewhat unimpressed, maybe it was a dud but I passed it on pretty quick.

[John]

11 hours ago, John said:

He is doing better than I am - I don't have any fixed FL eyepieces between 12mm and 8mm currently 🙄

I should have said between 12mm and 9mm inclusive. I have the 8mm Ethos of course 🙄

Plus I have a couple of zooms which do cover that range.

Edited September 9, 2023 by John