35 replies to this topic

[mloffland]

Explore Scientific 100 Degree Series 14mm Nitrogen-Purged Waterproof Eyepiece

By: David Knisely

[AZStarGuy]

Great review by a well respected member of the forum! I'm anxious to get a look through one myself. Ethos or ES 100 degree series is in the near future here. Thanks for a solid review!

[Darenwh]

Very good review. I'm glad they got it up prior to the introductory price changing even if it is only a few hours until the price goes up. I have loved my ES 14mm eyepiece and think it is a fantastic eyepiece. Looking at it and what has been written on the Explore Scientific Refractors makes me think this company is going to be around for a long time and is on it's way to being a very well respected company.

[SteveC]

Excellent report, David.

Aside from noticing a warm tone on the Moon, did you notice any loss of detail when observing globs, other DSOs, and the Moon, as compared to the 13mm Ethos?

[star drop]

Thank you for the review, David. It appears that one cannot go wrong purchasing one of their eyepieces.

[Jeff Morgan]

Great overview David, it looks like a viable option. I don't recall you dwelling on the performance in the 8" f/6 Newtonian. Did you feel the ES may be any more or less suited to different optical systems?

[jrbarnett]

David:

Very nice report. I really liked the criteria you chose to evaluate and the grading system (A, B, etc.) you chose to employ. It made for a very user-friendly review.

One thing that might help with context would be for you to provide your report card for other similar focal length superwides, ultrawides and megawides.

I would love to see Knisley "report card" for the 14mm Pentax XW, 13mm Nagler Type 6, 14mm Meade Series 4000 UWA, 13mm Ethos, 14mm Meade Series 5000 UWA, 16mm WO UWAN, etc. This would be a beutiful review format to serialize and then do a magnum opus "wrap up" report comparing all of the individually rated eyepieces.

Thanks for the excellent work,

Jim

[Project Galileo]

I can't wait to look through one. Thanks.

[David Knisely]

Excellent report, David.

Aside from noticing a warm tone on the Moon, did you notice any loss of detail when observing globs, other DSOs, and the Moon, as compared to the 13mm Ethos?

No, the eyepiece was a great performer on both planetary views and Deep-sky. In fact, because the field of view is so wide, the minor aberrations the eyepiece showed during testing generally are not much of a factor in the overall view. Under dark skies, I tended not to notice them nearly as much as when I was bench-testing the unit and deliberately looking for even the slightest problems. The aberrations were confined to the very outermost regions near the field stop, and to be frank, they didn't really detract from the overall view very much. As I said in the review, it isn't quite an Ethos, but it is a very worthy competitor. Clear skies to you.

[highfnum]

I got one of these -- and Im happy with it
the 13mm Ethos has one advantage
it can be used in 1.25 mode the ES cannot

but Ive used both and views are comparable

[Zuben el Genubi]

Thanks for an excellent report!

I too would be very interested in your 'report cards' for other ep's in this area.

I am also interested in how you assessed the cost/benefit ratio? This, I imagine, would be a highly subjective area to 'measure'. I'm an ethos fan, but the 'better view' does come at a cost... is it worth it? for me, yes, probably... but I could not answer that for others!

[David Knisely]

Great overview David, it looks like a viable option. I don't recall you dwelling on the performance in the 8" f/6 Newtonian. Did you feel the ES may be any more or less suited to different optical systems?

It worked pretty well in the 8 inch f/5 Newtonian, although because of the coma issue in the scope (fairly visible in a 1.38 degree true field of view), much of the time, we used it with the Tele Vue Paracorr in place, extending things to f/5.75 (1.2 degree true field). The view in my 100mm f/6 refractor was what really caught my eye, as it sort of had the same effect of "pulling you into the eyepiece" that I first saw with the 17mm Ethos, although perhaps not quite as strong as with the Ethos. Clear skies to you.

[square_peg]

Good write up, David. Well done.

The ES 14 looks like a pretty good value.

[David Knisely]

David:

Very nice report. I really liked the criteria you chose to evaluate and the grading system (A, B, etc.) you chose to employ. It made for a very user-friendly review.

One thing that might help with context would be for you to provide your report card for other similar focal length superwides, ultrawides and megawides.

I would love to see Knisley "report card" for the 14mm Pentax XW, 13mm Nagler Type 6, 14mm Meade Series 4000 UWA, 13mm Ethos, 14mm Meade Series 5000 UWA, 16mm WO UWAN, etc. This would be a beutiful review format to serialize and then do a magnum opus "wrap up" report comparing all of the individually rated eyepieces.

Thanks for the excellent work,

Jim

Thank you very much. I first used the letter grading on my review of the 8.5-12mm Speers Waler as an experiment, and it appears that it was successful. I don't have some of the eyepieces you mention, but I do have the "original" 1990's vintage Meade 14mm Ultrawide (flat-top and not volcano top) which is no longer made. At the time I received it, it would probably have graded-out as follows:

Construction: A

Field of View: A

Astigmatism correction: B+

Lateral Color correction: B+

Distortion Correction: B

Curvature of Field Correction: A+

Eye Relief: B+

Cost/Benefit Ratio: A

Overall Optical Performance: B+

My next eyepiece review will probably be the Hyperion 36mm Aspheric, so stay tuned! Clear skies to you.

[Downward Bound]

Another great review David. Thank you!

[Mr. Bill]

David

Do you know whether this is reverse engineering of the Ethos or a uniquely independent design?

[David Knisely]

From the overall performance and arrangement, I would say that the ES 14mm does not appear to be just a copy of the Ethos. Clear skies to you.

[kfred]

Good to know that TV has some competition in the 100 degree EP field.

Fred

[BillP]

Great report David

[cuir]

Great paper.

As always, information is clear and on point. Keep writing.

[JakeSaloranta]

Looks very nice but 500$ for one eyepiece is insane I get my rent paid for less.

/Jake

[David Knisely]

Looks very nice but 500$ for one eyepiece is insane I get my rent paid for less.

/Jake

The 14mm ES is selling for $400 (with the rebate) while the 13mm Ethos runs around $540 or so. Yes, price is a problem, but if you want that extreme field of view with halfway decent image quality, you do have to pay for it. Clear skies to you.

[Jeff Morgan]

Looks very nice but 500$ for one eyepiece is insane I get my rent paid for less.

/Jake

Yes, but you pay rent every month. A good eyepiece lasts as long as you want. Isn't rationalization wonderful?

[JakeSaloranta]

Yes, but you pay rent every month. A good eyepiece lasts as long as you want. Isn't rationalization wonderful?

I think I'm still going to stick with my Celestron Omni $40 each

[David Knisely]

Yes, but you pay rent every month. A good eyepiece lasts as long as you want. Isn't rationalization wonderful?

I think I'm still going to stick with my Celestron Omni $40 each

They are kind of a "generic" Plossl of the symmetrical variation, and offer farily decent performance, although they can hardly be considered to be "wide field" by any stretch of the imagination (apparent fields in the 43 degree to 52 degree range). They aren't too bad for the money however. Clear skies to you.