At this year's Stellafane, I had a chance to look through the 21mm Tele Vue Ethos prototype on Friday night. Al Nagler was showing it off in Sky & Telescope columnist Sue French's 130mm f/6.3 Astro-Physics Gran Turismo refractor. We looked at NGC 7000 (the North America Nebula), NGC 6992 (the eastern portion of the Veil Nebula), M8 and M20, M31, and the Double Cluster. The Double Cluster was especially stunning.

On Saturday night, I once again had the opportunity to use the 21mm Ethos. This time one of the prototypes was in a 28" StarStructure Dob on the lower field and the other was atop Breezy Hill in a 28" f/3.6 ATM Dob that was entered in the telescope competititon. Both scopes were trained on M27. Later on, I saw a number of other DSOs including M11 through the 28" f/3.6 Dob and the 21mm Ethos.

The 21mm Ethos produces a bit larger true field of view than does the 26mm Nagler Type 5 and provided some excellent views.

http://www.televue.com/engine/page.asp?ID=2

http://www.televue.com/engine/page.asp?ID=312 

Dave Mitsky

Without a doubt an excellent eye piece! However with that price I get my rent paid for nearly 3 months which makes the price pretty insane for a single item no matter how good it is. Worth a try if anyone in the entire country ever gets one...

/Jake

It looks like Explore Scientific was anticipating the 21mm Ethos.

http://www.explorescientific.com/eyepieces/100_degree_20mm.html

Dave Mitsky

We used the Explore Scientific 14mm eyepiece in a number of large dobs this weekend at CSAC. I think their idea (and it's a good one) is to provide three of these eyepieces so a user can pick any two of them at a price that's only 50% more than a single Ethos.

The 14 is very sharp to the edge. I've seen two different Ethos eyepieces and the way I'd compare them is to say that the Ethos is easier to use, but the image quality is about the same.

In the Explore, I had to put my eye very near the exit lens to see much of the field, whereas with the Ethos the experience was a lot like using a Nagler or Panoptic. If I had unlimited personal funds, I'd go with the Ethos, but since I don't then the idea of a couple of Explores is very tempting.

One thing I should point out: with the 14mm in my C-11, M-27 just about fills the field of view (takes up about 2/3rds of it. That is way cool.

Our group at McDonald Observatory reported last month that using a 13mm Ethos in the 82" telescope produced an image of The Ring Nebula that completely filled the field of view and showed many stars visible Through the nebula. Way, way cool.

So, now all I need is an 82" telescope!

Thanks for the comparison, Jeff.  It's good to read a head-to-head account, and it sounds like the Explore eyepieces may give the Ethos a run for their money.

chipdatajeffB:

So, now all I need is an 82" telescope!

Don't we all!

This is off topic as the originlal post was about the 21 ethos eyepiece but thanks for the info on the 14ES eyepiece with the C11, Jeff.  I was wondering how they and the other 100 degrees eyepieces would perform in the SCTs (saving to get more aperature).   The prices for the ES line is more in my ballpark and I was thinking of a 14mmES for my W/O M110 refractor but wanted to make sure it would perform well should I find a large aperature SCT.  

Sorry Dave for being off topic, but I have a couple of Naglers and from the report, know that I would have no problem with it either in my refractor or future scopes.  (It's just the price, whatever that may be, that's the concern). 

Ray