`TV-85` refractor
IN THE SHOPS
TeleVue ‘TV-85’ refractor
Ninian Boyle gets his hands on TeleVue’s 85mm refractor, which is perfect for visual astronomy or
astrophotography while also making a great travelling telescope.
T
eleVue is an American company who are
perhaps more famous for their eyepieces than
telescopes. That said, they do have a fan base for
their range of telescopes from 60mm to a substantial
127mm diameter aperture. I have been familiar with
and impressed by their products for many years and so
relished the chance to look at one of these telescopes in
detail and with a dispassionate eye.
The TV-85 is an 85mm (3.5-inch) aperture
apochromatic refractor presented in a substantial padded
case with die-cut foam, made capable of housing other
accessories such as eyepieces. Included in the bag is a
‘standard’ 20mm TeleVue Plössl eyepiece, a two-inch to
1.25-inch adaptor and a TeleVue ‘Everbrite’ two-inch
diagonal mirror. At first glance the whole package oozes
quality, which is what you might expect considering the
price tag! Another accessory that used to be an ‘optional
extra’ is the ‘Focusmate’ 10:1 reduction fine focuser, now
included as part of the package. This too screams high
quality. The focuser itself is a beautifully engineered
rack and pinion unit and the addition of the Focusmate
renders this buttery smooth and a highly controllable
delight to use. But is this quality only found in the
presentation and the accessories?
A close-up of the TV-85’s focuser and locking screws.
The TV-85’s
padded carrying
case, which both
protects the
telescope when it
is not in use and
makes it easier
to carry while
travelling.
84 | Astronomy Now | November 2013
The telescope tube is solidly built and finished in
a hardwearing ivory coloured textured paint. I am not
sure why TeleVue chose to give the paint texture, but I
can only assume that it was to aid safe handling of the
telescope in cold, damp conditions. The lens cell itself
is a separate black anodised section with a sliding dew
shield. This extends out past the lens cell some three
inches and is lined with black felt that helps it to wick
moisture away from the lens; a nice touch. The mount
ring is a very solid clamshell device with a recess cut and
tapped both sides to accommodate either the TeleVue
‘Qwik Point’ red-dot finder or the much classier (and
more expensive) Starbeam finder. The other end of the
tube houses the focusing unit and tapers down to the
draw tube, a substantial black anodised metal tube that
sits snugly inside the focusing unit giving no ‘play’ in its
movement that I could detect, when racked in and out.
The TV-85 is designed with visual use in mind. You
can only bring the image to focus using the diagonal.
However, you can use it ‘straight-through’ with the
addition of a three-inch extension tube; this is also
necessary if you plan to use the scope for imaging.
One of the other nice features of the telescope is the
use of two capture screws to hold the diagonal, extension
tubes, or other accessories. These in turn press onto a
brass ring inside the draw-tube thereby minimising the
risk of marking your nice quality eyepieces or other
equipment. There are also two similar screws that mount
through the telescope tube and hold the draw-tube
firmly in place to ‘lock’ the focus so heavy eyepieces or
cameras do not disturb your carefully acquired sharp
focus. This is especially important when imaging.
No collimation needed
The objective lens is covered by a very solid metal,
screw-on cover with a satisfyingly long thread, although
this could get troublesome if your hands are cold! Once
removed, you can see the objective lens itself sitting
IN THE SHOPS
neatly in its cell. It is very unusual to have to collimate a
refractor telescope, especially one of this quality and the
TV-85 is factory set with no obvious way of adjusting
this should the need arise. The only way to get to the
collimation screws, cleverly disguised with a neat blob
of a black waxy material around the outside of the lens
cell, is to scrape off the wax to access the screws. As this
would likely invalidate your guarantee, it is not to be
recommended and you should send your telescope back
to TeleVue if it requires collimating, as they recommend.
The lens itself is a thing of beauty. It is an
apochromatic doublet lens of 600mm, giving a focal
ratio of f/7. Apochromats are designed to eliminate
all false colours from the image. There are many such
telescopes that do this with greater or lesser success;
the TV-85 does it superlatively. On a bright near
full Moon, I could detect no false colour whatsoever.
Stars were absolutely pin-sharp and the sense of being
in space when looking through a low power, wideangle eyepiece is astonishing. I wanted to see how the
telescope handled serious magnification so I inserted
a high-power eyepiece, in this case a 3mm TeleVue
Radian along with a TeleVue 2.5x Powermate amplifier
that gave a magnification of 500×! Through high, thin
cloud, Saturn was still recognisable although very dim,
but even at this extreme magnification some detail was
discernible. At 200× the planet was a joy to view, with
the Cassini Division in the rings clearly visible, as well
as subtle variations in the cloud belts of Saturn itself.
Without a doubt though, it is the wide vistas where
the TV-85 really excels. With a low power, wide-field
eyepiece the views are nothing short of stunning.
Staring down
the barrel of the
TV-85, showing the
objective lens and
the dew shield up
front.
A side profile of
the TV-85, showing
the Starbeam and
mounting ring. All
images: Ninian
Boyle.
“THE LENS ITSELF IS A THING
OF BEAUTY – STARS WERE
ABSOLUTELY PIN-SHARP AND
THE SENSE OF BEING IN SPACE
WHEN LOOKING THROUGH A LOW
POWER, WIDE-ANGLE EYEPIECE IS
ASTONISHING.”
The other important question to ask of this telescope was
“is it good for imaging?” TeleVue produce a field flattener/
reducer for this telescope and using it with the TV-85 brings
the focal ratio from f/7 to f/5.6, a very nice focal length for
imaging many deep-sky objects. This allows the telescope
to be used with both a dedicated CCD camera as well as a
DSLR. With optics of this quality, you almost cannot fail to
produce decent images. The only criticism I can make of this
instrument is that the dew shield sometimes slipped when the
telescope was pointing at the zenith.
In conclusion I have to say that I am very impressed with
the TV-85 for its versatility, flexibility and first class optical
quality. It would make an excellent telescope for the serious
imager and visual observer as well as the casual observer, and
also comes in a more expensive version with a brass finish.
It is the sort of telescope that is small enough to be taken
on holiday or used as part of a semi-permanent set up in an
observatory.
Visit Ninian Boyle’s website Astronomy Know How at
www.astronomyknowhow.com.
At a glance:
The TV-85
Type:
Apochromatic refractor
Aperture:
85mm
Focal length:
600mm
Focal ratio:
f/7
Weight:
6.1 lbs (2kg)
Accessories:
Two-inch, dual speed, rack and pinion ‘Focusmate’ focuser,
two-inch Everbrite diagonal, dew shield, tube rings, 1.25-inch eyepiece
adaptor, 20mm Plössl eyepiece, carrying case
Price:
£2,049
Details:
www.televue.com
Available from:
The Widescreen Centre (020 79352580)
November 2013 | Astronomy Now | 85
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Republished with permission
from the November 2013 issue
of Astronomy Now
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© 2013 Pole Star Publications Ltd
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