Subject: re: WTB: Telescope
Date: Jul 25 14:01 PD 1995
From: Michael Price - michael_price at mindlink.bc.ca


Hi Tweeters,

In the discussion about scopes, I'm surprised the Optolyth TBG-80 (TBS in
the offset versions) hasn't come up for comment, given that its seems to
have been designed specifically for a cool, moist climate with marginal
light conditions such as Cascadia. To excerpt publicly from my private
response to Stuart's query:


Except for a so-so zoom (the image width of which, I learned, could be
increased by rolling back the rubber eyecup and sticking your eye *close* to
the eyepiece), I thought the TBG-80 series (TBS-80 in the offset version)
the pick of the crop after the Kowa. And that was *without* the ED Prime glass.

Selling points:

--80mm gives 17% more lightgathering area than the best 77mm scope.

--rubber-armored, effectively so. An acquaintance dropped his TBG-80 from
chest-height onto the terrazzo floor of Heathrow Airport, watched in horror
as it bounced twice, the first time higher than his knees. No damage.

--titanium alloy body makes it very light and hugely strong for its size.
The first time I was handed one I damn near threw it up through the ceiling,
I was so unprepared for its lightness of being. Turns out to be strong
enough to use as a bat in pickup baseball if the birding's slow :-)

--effectively sealed interior: fog- and waterproof--a real plus for the
Cascadian climate, particularly in winter, when the temperature gradient
between warm car and outside cold moist air fogs up any unsealed scope or bins.

--an innovation which I'm amazed no-one else has copied is the small thin
pane of coated glass in the body of the scope just in front of the eyepiece
mounting; this prevents dust and junk from entering the body of the scope,
and it's easy to clean. If you change eyepieces on a Kowa, for example, you
open the unsealed body of the scope to all sorts of crud. After a few years
of changing eyepieces in an unsealed scope, you have to clean the whole
scope inside and out; in the Opto, just the glass pane once in a while.
Brilliant.

--I field-tested an Optolyth TBG-80, conventional glass, with 15X--60X zoom
against a Kowa TSN-2 (conventional glass). How's this? Birding until 10.30
PM (sunset at 9.15) and *still* being able to separate Western and
Semipalmated juvs. at 100 meters; then, seeing that Saturn was high in the
south, turning our scopes on it, seeing the Cassini Division in the Rings
*and* spotting Titan off to the side (the Kowa 2 couldn't). Performance was
about equal, which surprised me until I realised what was holding the Opto
back was the less than optimum zoom eyepiece, like a racing car denied its
top gear. Had the zoom eyepiece matched the objective as well as the Kowa
zoom matched its, I think the Opto's performance with the untreated glass
would have *easily* outdistanced the TSN-2, and even been the equal of the
Kowa TSN-*4* and maybe even a titch better. Where the Opto is *magnificent*
is when it is equipped with the 30X super-wide (called the 30 wide-wide)
angle lens. An image that is more like that provided by a Questar than any
other spotting scope.

(snip)

Imagine what an ED Prime TBG would do!

(snip)

The new Fujinon ED Prime 80mm may be the best spotting scope ever if the
optics are the equal of their bins. Usually the brightest, sharpest image on
the market

(snip).

Michael Price
Vancouver BC Canada
michael_price at mindlink.bc.ca