Stellarvue Nighthawk Review
Twenty years ago, having just got back into astronomy, I was
looking for a cheap way to get a premium refractor. No cheap Chinese APOs back
then. Stellarvue had just started up and I simply
couldn’t decide whether to get their long-focus 80mm achromat (the 80/9D) or
their short-focus version (the Nighthawk). I loved the look of the Nighthawk,
but wanted the planetary performance of the 80/9D. Function won over form and I
bought the longer scope. Years later I got a Nighthawk to see if I had missed
something.
At
A Glance
|
Telescope |
Stellarvue Nighthawk |
|
Aperture |
80mm |
|
Focal
Length |
400mm |
|
Focal
Ratio |
F5 |
|
Length |
~450mm |
|
Weight |
~3 Kg |
Data from SV.
Design and Build
Though the Nighthawk looks a lot like an ST80 and has a
similar optical spec’, it is a much heavier and more substantial telescope
which has much more in common with the 80/9D than at first glance. The
Nighthawk has an individual serial number and from the look of it, SV sold
thousands of these back in the day.
Optics
The lens is a basic air-spaced achromat and has a similar
spec to an ST80 – 80/400 F5. It looks well-coated in typical China green. Just
like the 80/9D, the tube internals include knife edge baffles.
Whilst the short-tube Synta
achromats have a large air gap to help correct aberrations, the Nighthawk has
just a basic foil-spaced lens and performs rather worse, so that false colour
is at Star Travel 102 levels.
Tube
Both the large dew-shield and the telescope itself are made
from heavy-gauge aluminium like the 80/9D. Unlike the earlier 80/9D, that tube
ring is a chunky thing as well. The cell isn’t adjustable, but threads onto the
tube; the sliding dew-shield also threads on, making it easy to dismantle for
travel (incidentally the threads are coarse enough for regular use; anyone who
has tried to re-install a Takahashi dew-shield with its micro-fine threads will
know what I mean).
With the dew-shield retracted the Nighthawk is a very compact
scope, but unfortunately the clamshell prevents full retraction, so with the
clamshell in place (removing it means allen bolts) it
is much less compact than it might be.
Whilst fit and finish are good, the parts solid and
well-painted, the Stellarvue lacks the refined
CNC-milled parts and fine castings of a Tak’ or a
Tele Vue.
The clamshell tension adjusts with big knurled knobs and so
is very easy to use – a real improvement on the fiddly thumb-screw on a TeleVue clamshell.
Focuser
The rack and pinion focuser is a metal
Synta-type unit and works well, but is not up to the
standards of modern premium scopes, though this one does have the nicer alloy
SV knobs rather than the plastic ones on the 80/9D and a better finish too.
Like the focuser on the 80/9D it’s attached by
screws, not threads like the lens cell.
Unlike an ST80, the Nighthawk’s focuser takes 2” eyepieces.
This gives the potential for a much larger field of view – great for surfing
star fields, use as a super-finder, or for budget imaging. The Nighthawk is
capable of a binocular-like 6.6° field compared to the ST80’s 3.9°, almost three times the area.
Mounting
The SV clamshell has ¼-20 threads that allow it to go
straight on a Tele Vue mount head as shown above (on a TV Panoramic) and a
centre one for a photo tripod (it would have to be a big one).
SV clamshell is well made but massive, threaded for Tele Vue
mounts.
In
Use – Daytime
Daytime views are limited by severe chromatic aberration. The
overall quality of the view can be gauged from my standard daytime
birds-in-branches shot. Despite the false colour, in-focus parts are pin-sharp
though.
In
Use – The Night Sky
The lens is very sharp, pops into focus and has an excellent
star test as well. So the optics are first rate and
they star test every one at the factory, so quality
control should be good.
The Moon
Just as you would expect from the daytime prime focus shot
above, there is quite a lot of chromatic aberration which limits magnification on
the Moon to perhaps 80x, beyond which the bright highlands start to wash over
with purple. Even so the Nighthawk provided a great view of the Moon at 80x
with a 5mm Nagler – sharp and detailed.
Deep Sky
As you would expect, stars are tight and the field quite
flat. Stray light is very well-controlled thanks to proper baffling and general
deep-sky performance excellent for the aperture, with the high contrast you
expect from a small refractor. M42 showed a lot of detail in the nebulosity
with a glittering Trapezium easily split out at low power and a flat, wide,
diamonds-on-velvet view.
Overall performance for deep sky is helped by the potential
to use 2” eyepieces.
Very early Nighthawks were said to have issues with
vignetting by the focuser drawtube, but if mine suffers from this problem it is
too minor to have much impact on the measurable exit pupil.
Summary
The Nighthawk is a decent grab-n-go refractor (though the CA
will get in the way for serious imaging use). However, compactness and build
quality are not in the premium class. It has fine optics and gives very good
views for an 80mm achromat; but so does an ST80 whilst
being much cheaper and easier to mount.
The key difference is the 2” focuser – if you need it then
the Nighthawk is an option, if not buy an ST80, ludicrously cheap as they are.
Cautiously recommended if cheap, but don’t think you’re
getting the optical or mechanical refinement of a Tele Vue Ranger or Pronto.
The Nighthawk really is just an achromat.
Addendum: Stellarvue don’t seem to
be able to decide whether they are high-end or low-end. They advertise low end
re-badged Chinese fare alongside big-money premium large refractors. In my
opinion this is a mistake. Makers like AP, Tele Vue, TEC and Takahashi have
understood the need to remain a premium alternative in the face of budget
competition from brands like Sky-Watcher (who now, let’s face it, make a great
telescope) that hardly existed when SV set up a decade ago.