Rodger W. Gordon’s Thoughts on the Tele Vue-85 and Questar 3.5″

Al Nagler (“Dr. Dioptrx”) with his Tele Vue-85 and Questar 3.5″.

Rodger W. Gordon has been an amateur astronomer since 1952 and has written over 300 articles for various amateur astronomy publications. Having owned hundreds of eyepieces, he has been known as the “Eyepiece King” of the hobby. In his long career, he has worked for Edmund Scientific, Vernonscope, Optical Techniques, and has consulted for Questar.

At the Northeast Astronomy Forum (NEAF) in April 2007, we introduced the 13mm Ethos 100° eyepiece. The overwhelmingly positive response to it at ensuing star-parties led me to explain why the view elicited so many enthusiastic “WOW!” comments in an essay on our website “The Majesty Factor – The Nexus of Contrast, Power, Field” (also on our mobile site). As an example of the enthusiasm, I included the following:

Right after NEAF, Rodger Gordon, a well-known “eyepiece junkie,” 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.

Knowing Rodger’s long experience with astronomical equipment, and the fact that we both own Questar 3.5″ telescopes, he sent me the following letter, written July 17, 2020, about comparing his Questar 3.5″ to his son’s Tele Vue-85.  I like to call the Tele Vue-85 my “Goldilocks” telescope because it’s just the right aperture and size for everything from a quick “no excuse not to go out” observing session to a full night of enjoyment. However, if I judged telescopes by their sheer beauty and elegance, I guess I would rate my Questar as the “Majesty Factor” winner 😉 .

Dear Al:

On June 26, 2020 my son (here on a visit) compared his Tele Vue-85 to my 3.5″ Questar with its 1/67λ RMS optics. My son also has a 3.5″ Questar. We had seeing of 8-9 on the 0-10 ALPO scale (0 worst, 10 best). Favorably placed were the lunar craters Theophilus, Cyrillus, and Catharina. We examined these craters for 1 hour and 15 minutes, sometimes using a Schott OG-530 yellow filter (available from Edmund Optics).

Magnification on the Questar 110x, on the Tele Vue-85 – 100x. The image quality in both scopes is superb – no hints of chromatic aberration in either scope. Crater detail equal in both with or without the filter. The image was somewhat brighter in the TeleVue-85 probably due to the fact my Questar has standard magnesium fluoride coatings and the slightly higher power used on the Questar. I know you have a variety of scopes including a 3.5″ Questar so I thought you would be interested in our comparison results.

Sincerely,

Rodger W. Gordon

 

Specifications:
Tele Vue-85 & Questar 3.5"

 Aperture
(mm)
Focal
Length
(mm)
f#Max
Field
(°)
Questar 3.5"89130014.60.94
Tele Vue-858560074.4
 
the-3-craters – (in colour) by flickr user Peter Sculthorpe. All rights reserved. Used by permission. Lunar craters Theophilus, Cyrillus, and Catharina at First Quarter. SN-10″  F/4 Schmidt-Newtonian and 5x Powermate with 680nm IR filter and ZWO ASI174MM camera for luminance and no filter with Sony α7s DSLR for color. Best 600 of 1500 frames stacked in Autostakkert-3, Wavelets in Registax 6.0, and Photoshop 2020. Image was taken 30 May 2020 from Merseyside, UK.
Meet the Tele Vue-85!
Available in ivory or green OTA (above shown with optional accessories). The OTA includes: sliding metal dew shield, screw-on metal lens cover, Focusmate dual-speed 10:1 focuser, and soft carry case. Optional accessory package (TVP-3373) includes tube ring-mount with 1/4-20 mounting threads, 2″ Everbrite (99%, 1/10-wave) Dielectric mirror diagonal with brass clamp ring, a 1¼” ‘Hi-Hat’ eyepiece adapter with brass clamp ring, and 18.2 mm DeLite eyepiece with 20-mm eye-relief that yields 1.8° true field of view at 33x in this scope.
With an 85mm APO (Doublet) objective and 600mm focal length, this f/7 refractor offers a combination of optical performance and airline portability that delights amateur astronomers, birders, and reviewers alike. Resolving close double-stars, viewing lunar detail, viewing deep sky objects, and photographic uses were all reported in Sky & Telescope as: “Truly awesome! …Incredible!…the view almost blew me off my chair!…” The conclusion, “…an extremely powerful, compact instrument capable of delivering stunning images of the universe.”
 
Maximum field-of-view is 4.4° (with our 41mm Panoptic at 14.6x or 55mm Plössl at 10.8x) allows use as a self-finder. Optional Nagler  3-6mm Planetary Zoom yields 100x – 200x in this scope for obtaining optimal planetary observing power to match the seeing conditions. The addition of the TRF-2008 0.8x Reducer/Flattener converts the Tele Vue-85 to 480mm f/5.6 for fast, flat field photography with any camera that accepts a T-Ring.
 
See more info on the Tele Vue-85 page and please see our recent blog posts on the Tele Vue-85 to learn first-hand how this scope is used in the field.
 
Did you observe, sketch, or image with Tele Vue gear? We’ll like your social media post on that if you tag it #televue and the gear used. Example:
#televue #tv85 #ethos #jupiter

 

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