Televue ETH170 ETH-17.0 17MM Ethos Eyepiece

by Tele Vue

Product Details

• Item Weight: 2.3 pounds
• Shipping Weight: 2.5 pounds (View shipping rates and policies)
• ASIN: B001NJ2Q4A
• Item model number: ETH170
• Average Customer Review: 4.0 out of 5 stars  See all reviews (2 customer reviews)
• Amazon Best Sellers Rank: #174,865 in Office Products (See Top 100 in Office Products)
  • #8 in Office Products > Educational Supplies > Classroom Science Supplies > Telescope Accessories
• Date first available at Amazon.com: June 17, 2003

Product Description

A 100° apparent field of view is a truly astounding number by any astronomical standard. Given that your 'mind's eye' can concentrate upon approximately 50° of a viewing field at once, doubling that amount results in a view that you could feel like you're "just falling into". For any given magnification, an Ethos will show a whopping 50% more sky than the previous widest oculars. Sharpness is inherent to the Ethos' optical design, and contrast is maximized through intelligent use of flat baffle finishes and ultra low reflectivity, high-efficiency coatings tuned to the composition of each element. The Ethos does the job of many eyepieces, delivering the true field sizes of longer focal length, narrower apparent field eyepieces with the benefits of higher power and darker sky backgrounds. The 17mm Ethos fits 2" focusers/diagonals. Though it has a respectable 15mm of eye relief, it accepts Tele Vue's DIOPTRIX eyepiece astigmatism correctors so that even astigmatic viewers can observe without having to use their glasses.
FEATURES; Accepts DIOPTRIX astigmatism correcting lenses so astigmatic users can enjoy sharp viewing without their glasses
Can be combined with Barlows and Powermates for higher magnifications without vignetting.
Accepts 48mm filters

Customer Reviews

Most Helpful Customer Reviews

1 of 5 people found the following review helpful:

5.0 out of 5 stars You dont know what your tal;king about!, April 19, 2010

By 

George D. Andrew "geodandrew" (White Plains NY) - See all my reviews
(REAL NAME)   

This review is from: Televue ETH170 ETH-17.0 17MM Ethos Eyepiece (Office Product)

The above review is from a person that owns a telescope thats cheaper then the EP. 40 years? As a DSO with a 20" F5 Obsession I can tell you this will give you great views. Many DSO will objects will make you think that you can go swimming in them.

10 of 21 people found the following review helpful:

3.0 out of 5 stars Quirks Don't Warrant Steep Price, January 20, 2009

By 

Fred Rayworth (Las Vegas, NV United States) - See all my reviews

This review is from: Televue ETH170 ETH-17.0 17MM Ethos Eyepiece (Office Product)

I had a chance to run this eyepiece through its paces on 17 Jan 09 and I must say, for a deep sky observer with 40+ years experience, I was disappointed.

First off, I'm a "hard-core" deep sky observer, and I've learned over the years that to see the really faint stuff, the more lens elements and the more magnification (to a point, anyway), the more light is sucked out of the view. This monster is a case in point.

When I first plugged it in, I was quite impressed with the super-wide field of view and the pinpoint stars all the way to the edge, even in my 16" f/4.5 LightBridge. I have no complaints about the initial view, and especially when I put it on the Orion Nebula and a few open clusters. Wow!

However, the view was so wide, I could not help opening my other eye and really having to strain to keep it closed, to the point that I had to hold it closed with one hand as I guided the scope with the other. In fact, after a few minutes of this, it started to give me a headache. On top of that, the sweet spot in the eye lens was tight and I had to roll out the rubber eye guard, just to give me a perspective on where to put my head.

Though those quirks were minor, the deal breaker for me was what it did to super-faint objects. Case in point is the Horsehead Nebula. I'd just got an Orion H-Beta filter for Christmas and was anxious to try it out. Upon the second try, I found the Horsehead with the filter plugged into my Orion Q-70 eyepiece. Though the field edges are classic "fishbowl," I don't mind at all. It was the first time I'd seen it visually since 1997.

I then tried the Ethos with the filter and though it actually showed a wider field than the lower power 26mm, and the stars were pinpoints right to the edge, the Horsehead was completely invisible. I was patient and stayed on it for several minutes, but besides the fact that the field is so wide, it brought in some surrounding stars that I could easily block out with the Q-70, and the contrast didn't bring out the dark area.

To make sure it wasn't just the Horsehead, I tried the EP on a couple of Herschel 2 galaxies I'd found. Though I could see some detail within them, I saw them brighter and with just as much detail with the cheap old Q-70.

If you are into wide field general viewing or sweeping, this may be for you. However, for deep sky objects, especially smaller ones, the field is too wide and it is hard to frame smaller objects. I don't recommend it.

I don't know about you, but I don't think it's worth the $750 price tag.