Hello Folks,

The names TeleVue and Al Nagler  are well known in the  amateur astronomy community. With his forward thinking and revolutionary telescope and eyepiece designs in production since 1977.Al  began his career  as an amateur astronomer who enjoyed building scopes.

Al Nagler  eventually became involved in the design of the NASA Apollo program astronaut lunar landing visual simulator by designing a probe which simulated a field of up to 140 degrees, amazing or what?

One of the other driving forces at TeleVue that you do not often hear about is his spouse, Judi Nagler.
Judi recently retired from TeleVue but you can bet, that no matter what Al was doing, Judi had her finger in the pie too!! She was always  helping Al at Televue displays both at commercial venues and conventions such as NEAF in New York. As they say, behind every great Man, is great Woman and Judi is certainly that.

Every once in a while, something New and Exciting comes along in the Telescope industry.  The TeleVue 13mm Eyepiece  Ethos is one of those.

We Thought you might enjoy this article by the  Majestic Al Nagler on the New Ethos Eyepiece.

It is not as technical as it first may appear, and  the quote by Rodger Gordon, an eyepiece expert, is rather amusing!

Since it's a tad too cold (or too cloudy)  to step outside and observe these days , we thought some reading might be in order. 

Hey, you can even buy heated coats now (quite popular in Florida at the moment) , and with the heated electric socks, that is a great combo for getting electrocuted if you step in some slush, so please be careful. 

Happy New Year!

Your Friends at Khanscopes...........

 

Ethos™: The "Majesty Factor"
The Nexus of Contrast, Power, Field

- an essay by Al Nagler

 

After showing Ethos at a number of events since April 2007, we can safely conclude it brings the observing experience to a new level. This is based solely on user's reactions to views of familiar objects, not on any prejudgments, publicity or hype on our part. While we were quite confident of success, we wanted, and still want, to explore all the ramifications of what a sharp 100° field really represents.

Right after NEAF in April, Rodger Gordon, the acknowledged "eyepiece junkie" of all time, wrote me "Definitely the finest wide-angle eyepiece I've ever seen. If God is an astronomer, this is the wide-angle eyepiece he'd choose. You can quote me." Thanks, Rodger. I waited until now to avoid "priming the pump", so to speak before quoting your unbridled enthusiasm publicly.

For some time, I've been pondering just why the response has been so overwhelmingly positive. And if I really understand why, is it possible to quantify? My views of the Double Cluster at Stellafane pointed the way.

The 1991 article I wrote for Sky and Telescope on magnification provides the key. A major conclusion for low power states: "The best view occurs with the highest power that comfortably includes the target object. Higher powers darken the background sky, reveal fainter stars and show more detail. The resulting smaller exit pupil also minimizes the effects of eyesight defects."

Considering the potential of Ethos, let me posit a more general conclusion:

For deep sky viewing of star fields, open and globular clusters, nebulae and galaxies, choose the highest power that frames the subject, so long as the sky background does not reach black, and the atmosphere does not degrade the resolution. The smaller exit pupils permit a darker sky background which achieves greater contrast against the fixed brightness of stars, while the greater magnification reveals more structural details on extended objects. Using eyepieces with larger apparent fields increases the magnification potential.

The result is an increase in what I would call the Majesty Factor, the nexus of contrast, power and field.

It's clear that the largest possible apparent field for a given true field yields the most magnification for greater resolution, with a darker sky background for more contrast as a result of the smaller exit pupil. I believe this combination of contrast, power and field causes the typical "wow" reaction - the Majesty Factor. I think Tom Trusock said it most succinctly in his Starfest (Canada) report:

"The same true field at higher magnification means that you'll see blacker skies and more detail." Dennis di Cicco in his 5-star review of Ethos in his October 2007 Sky & Telescope review noted something similar: "Observing with the 12-inch scope, I typically bounce between a wide-field eyepiece for star-hopping and a high-power one for detailed views. But the Ethos gave me both. The field was large enough to star-hop, and the magnification was high enough to bring out faint stars and resolve details in galaxies and star clusters." (He coincidently also illustrated field sizes using the Double Cluster.)

Let's try to quantify the so-called Majesty Factor. While we cannot quantify the majesty of a great symphony, work of art or edifice, I think a meaningful Majesty Factor is quantifiable for those great deep sky views. Here's how:

Let's consider a range of possible eyepieces with apparent fields of 50°, 60°, 68°, 82° and 100°. Now let's pick an object, (like the Double Cluster) and let's say it's properly framed in the field of a 50° Plössl with a 26-mm focal length in an f/4 telescope so the exit pupil = 6.5-mm. Let's arbitrarily assign a factor of 1 to the power (magnification) of this telescope and a factor of 1 to represent the contrast for the 6.5-mm exit pupil. Therefore, for the given true field, the Majesty Factor = 1 (power factor) x 1 (contrast factor) = 1.

Now let's replace the Plössl with a 100° (apparent field) Ethos with a 13-mm focal length. This yields the same true field of view at twice the power with twice the apparent field and half the exit pupil. The 3.2-mm exit pupil is only ¼ the area of 6.5-mm, so the sky background darkens by a factor of 4 (contrast factor). The magnification power factor yields twice the detail or resolution. Therefore: 2 (power factor) x 4 (contrast factor) = 8x Majesty Factor

Working out the math for all the apparent fields listed above, we have:

 

- Al Nagler

www.khanscope.com

The Ethos eyepiece is available for $659. Due to the high demand for this eyepiece, we are currently sold out, and are taking orders for delivery in the near future. We are working with TeleVue to fulfill orders asap.
Price: $659.

To place an order call Toll Free 1 800 580 7160 or local 416 783 4140 or fax 416 352 1701

Don't Forget! TeleVue Telescopes are now on sale for a Limited time....for more information:

http://khanscope.com/newEquipList.cfm?catID=1&subCatID=1&manID=7