Tele
Vue Pronto Review
Tele Vue’s Ranger and Pronto were the
little scopes that got the Renaissance (sorry) in small refractors going twenty
years ago.
Small and beautifully handmade in the
USA, both had 70mm aperture semi-apo objectives and were made for Tele Vue’s
simple push-pull mounts: Ideal if you just wanted to plonk them outside and
take a quick look – at the Moon, an open cluster or two, even Jupiter.
The Pronto was my first experience of that new wave of
grab-n-go refractors. Up until then, I had always owned large telescopes and
the Pronto was a revelation. I loved its high quality, keep it simple design. I
loved, frankly, its chic looks with those ‘mag wheels’ for focuser knobs. I was
prepared to look past the fact that for a not-very-apo it was expensive, even
used.
In the end, the Pronto was replaced by
the TV-76 (both in the Tele Vue brochure and in my study) - a proper apochromat
with a larger lens and faster f-ratio that looked outwardly very similar. No
one will ever build anything like the Pronto ever again, because cheap Chinese
APOs mean a hand-built-in-the-USA semi-apo would never sell for what it costs
to make.
So
if you can find a nice one, does the Pronto make a good buy as a potential
classic, or is it hopelessly outclassed by that newfangled
Sky-Williams GoldCat 71ED?
At
A Glance
|
Telescope |
Tele Vue Pronto |
|
Aperture |
70mm |
|
Focal Length |
480mm |
|
Focal Ratio |
F6.8 |
|
Length |
~14” (36cm) |
|
Weight |
~2.7 Kg |
Data from Tele Vue.
Design
and Build
The TeleVue Pronto looks much like
the TV-76 which replaced it and the triplet Oracle that came before it. Unlike
those two scopes, though, the Pronto shared its optics with another Tele Vue -
the Ranger, which was a 1.25”-only helical focused lightweight that catered to
a wider use case (and weighed about half as much).
Optics
This is where
the Pronto is very different from the TV-76. The TV-76 has a 76mm (!) FPL-53
F6.3 doublet that is a full-on (more or less) apochromat and so good for
imaging and high powers as well as low-power deep sky.
In contrast,
the Pronto has a 70mm F6.8 doublet which uses cheap E.D. glass that doesn’t
(according to someone who should know) do that much to cure false colour
(chromatic aberration). Consequently, the Pronto is very much at the achromatic
end of semi-apos, though optical quality is high and
the objective is properly multi-coated.
Like almost
all Tele Vues, the objective is held in a slim,
non-adjustable cell, nudged into alignment on an optical bench and then fixed
in place with blind rivets (or perhaps filled screws). If this sounds crude,
believe me it makes the scope robust – I once dropped mine from about a metre
onto tarmac and it suffered no ill effects at all (really!)
Pronto shared
its 70mm F6.8 optics with the Ranger.
Tube
It is a very well made, compact, but quite heavy OTA finished
in cream pebble powder coat, or a mossy
metallic green, the latter perhaps a concession to birders who apparently
favoured the Pronto’s tack-sharp images. Inside, the
tube has no baffles; instead it is lined with the TV-standard flocking paper
that looks a lot like black-painted sandpaper.
The lens is
protected by a sliding
black anodised dew-shield: beautifully
machined, it slides with just the right friction. Like most modern TVs, the
objective is protected by a weighty thread-on cap that squeaks rather too much
in the small hours.
Personally, I think the Pronto and early TV-76, with gloss
anodising and chrome focuser tube, look better than the more recent ones with
their heavy-duty focusers and satin powder coat. The Pronto has a kind of
artisanal look to it that is virtually gone from astronomy these days.
A weight of
2.7 Kg doesn’t sound much, but the compact OTA feels very hefty and solid. By
comparison, a modern Borg 71FL would weigh maybe half as much (depending on
configuration). At just 15” long, it’s a slim and compact telescope though.
The Pronto
has all the period Tele Vue styling features, like gloss anodising and that
screechy thread-on lens cap.
Focuser
The Pronto has Tele Vue’s original
single speed 2” rack-n-pinion focuser with its characteristic cast body, serial
number plate and ‘mag’ wheels. This focuser was once fitted to almost their
entire line-up (apart from the Ranger). The focuser tube is thickly-chromed
brass; nice.
This is how a simple focuser should be.
When new and unmolested (lots of people tried to retro-fit the dual speed
pinion assembly, whereupon the shims fell out ruining the action), it was
super-smooth and free of image shift, with ample travel and properly designed
with no vignetting.
Mounting
The Pronto
comes with a clamshell ring that has a pair of outer ¼-20 threads to fit Tele
Vue’s own ‘Panoramic’ and ‘TelePod’ mounts using Tele
Vue’s lozenge-shaped Bakelite fasteners, along with a central ¼-20 thread if
you can find a photo head strong enough to take it.
The clamshell
has an Allen bolt on one side and a thumb-screw on the other. Adjusting tension
with the thumbscrew is easy, but removing the ring requires an Allen key. The
Allen bolt and thumbscrew were ferrous on the Pronto and so corrode; later ones
were stainless and make a cheap upgrade.
Tele Vue make
a Vixen-compatible dovetail that attaches to those outer holes and allows the
Pronto to fit most Vixen and Skywatcher mounts (an
EQ5 or similar is more than stable enough).
Clamshell has
three ¼-20 threads.
Vixen-compatible
dovetail.
Identical-looking
early TV-76 on Panoramic mount.
Accessories
The Pronto came with a nice soft case
(usefully cabin carry-on sized), a 2” mirror diagonal (not dielectric), a 1.25”
adapter and a 20mm Plossl eyepiece. Accessories to
buy included the Starbeam red-dot finder.
Numerous eyepiece options were possible
(of course), but the older 4.8mm Nagler was a
favourite for higher powers.
Pronto and Naglers
just go together.
Pronto and case.
In
Use – Daytime
There’s some false colour on
high-contrast subjects like birds in high branches, but the view is super-sharp
and contrasty at moderate powers – better than the
majority of prismatic scopes, even HD ones.
The Pronto can serve as a good casual telephoto
lens, but false colour spoils high-contrast areas, see example below.
This Pronto telephoto snap looks good,
until you zoom in to see the false colour.
In
Use – Astrophotography
The Pronto gave very reasonable starter
images of the deep sky, but with too much blue-violet bloating for ‘serious’
imaging.
Likewise, decent snaps of the Moon at
prime focus are easy and that false colour doesn’t show up nearly as much.
Pronto snap of M42 with slight tracking
error.
In
Use – The Night Sky
General
Observing Notes
Star images
are pin-point and given the conservative f-ratio, the field is quite flat for
visual use. It’s generally a great view, even if Pronto is ‘only’ a semi-apo.
The flocking works well to eliminate internal reflections and give good
contrast.
The
super-smooth and precise focuser is a pleasure to use and doesn’t run out of
travel for 2” eyepieces. Maximum field of view for a 55mm Plossl
is a generous 5.5° - well into binocular territory, so you don’t
really need a finder for bright stuff.
Overall, the Pronto continues to give
excellent views. I recall that when I first upgraded to the TV-76 I had them
out side-by-side comparing. The difference wasn’t nearly as great as their cost
difference might suggest.
Note: I owned
the Pronto ages ago, so I’ve cribbed the viewing notes for the Ranger (it’s
optically identical), which I tested recently alongside two Takahashi 60s.
Cool
Down
Cool down is quite fast, but this is a
heavy OTA with lots of metal, so it’s typically a bit slower than something
like an ST80.
Star
Test
Lens quality
is very good, easily diffraction limited and with smooth polish, so the star
test is good.
The
Moon
Just after
full, with Mare Criseum highlit
by terminator shadows, the Moon through the Pronto surprised me. A cold hard
ball full of detail was much as I expected at 32x. At 96x with a 5mm Nagler it was still a great view, albeit with a purple
fringe off the limb.
Increasing
the mag’ to 137x with a 3.5mm Nagler, the view was
still good. Yes, the purple was now bright and obvious, but it wasn’t washing
out the detail and everything stayed sharp and contrasty.
Short focus achromats don’t do that, Tele Vue’s own Renaissance included,
washing a lot more violet across the Moon’s craters at powers over 100x.
Back at the
Moon, I enjoyed the embayments and cliffs and
craterlets around Mare Criseum, bright Proclus with
its odd shape. Nearer the limb, I could make out Hummocks on the floor of
Gauss, the central peak in Hahn. I found the Messier twins and their bright
rays. Next night, the strange straight rille like a clock hand in Petavius was easily resolved in poor seeing.
One frosty
November Monday morning of excellent (8-9) seeing, I got up early and looked
out on a last quarter Moon, high in the sky just off the meridian, with Albategnius on the terminator. With a 3.5mm Nagler giving 137x, I could make out the craterlets like a
string of beads along Rima Hyginus and Rima Ariadaeus
disappearing into the lunar night.
The view was
sharp and full of detail: running down the terminator, I enjoyed Mons Piton
shining alone in Mare Imbrium near the ‘ring wall’ of
Archimedes, the sharp peaks of the Apennines, the slumped walls of Tycho in detail.
Clavius and its arc of craters.
Upping
magnification to a maximum 192x with a 2.5mm Nagler,
the view stayed surprisingly sharp with no softening. But now a wash of pale
lilac started just back from the dark limb, spoiling the view and reducing
contrast a little. In this respect, the Pronto outperformed the TV Genesis, but
the Takahashi fluorite doublets alongside could take higher powers in the
excellent seeing.
Overall, and
despite the purple rinse, the Pronto gave a very satisfying view of the Moon.
Mars
I caught
Mars low in the dawn sky at the beginning of an opposition year when it was
quite bright but just 3.8” in size. The Pronto showed a nice little orange disc
with just a trace of false colour at 96x with a 5mm Nagler.
Deep
Sky
Early before
dawn one frosty November morning, Gemini, Orion, Leo and Auriga hung in front
of my balcony twinkling coldly. I set the Pronto out and went deep sky
observing – honestly more fun than I’ve had with a scope since I can remember.
Just three
(of TV’s own) eyepieces were all I needed – a 32mm Plossl
(my most used eyepiece for 20 years), a period 15mm Panoptic and a 5mm Nagler T6 - giving 15x, 32x and 96x respectively. But even
just the standard 20mm Plossl, included with the
Pronto new, would give great deep sky views at 24x.
The Pronto’s optics give a very flat field with the perfect
lens squashing all the light into the tiniest stars across the field to give
strong star colours. For deep sky, false colour just doesn’t intrude visually,
even on brighter O-A stars.
I flitted
between Orion’s sword, the diamond Pleiades, brilliant but faintly misty,
Auriga’s clusters, the Double Cluster in Perseus. I split Castor and enjoyed
some simply beautiful star fields. Everything looked gorgeous, more so than in
a 60mm because the Pronto is grabbing 36% more starlight.
On another
night, I just about split the Double Double in
terrible seeing and moved on to a good view of the nearby Ring Nebula, it’s
shape easy to pick out with averted vision through a Nagler
7mm at 69x – much better than the FC-60, with a third less light gathering
aperture and that uncoated fluorite element. Similarly, globular cluster M15
was easier to pick out from Moonlight through the Pronto’s
70mm ED lens than the FC-60’s 60mm fluorite one.
The Pronto
is a very nice deep sky tool.
Summary
The Pronto looks lovely, is built to
last forever and is very robust. The focuser is wonderful if undisturbed.
It may be an ED-glass semi-apo in
theory, but it’s closer to being an achromat in practice. That means a dark
purple rim around the Moon at high powers (only noticeable over 100x) and too
much blue-violet bloat for serious imaging.
But the Pronto still delivers a
fabulous view, especially for deep sky, but of the Moon and most terrestrial
subjects at spotting-scope powers too. You won’t be disappointed by the view,
even today.
The Pronto remains a great scope and
something of an heirloom-quality classic.
Recommended as a classy grab-and-go, but don’t be tempted to
pay TV-76 money for one.