Stellarvue SV50 finder scope – spotter version
By Malcolm Bird
My name is Malcolm Bird from Kingston, Canada. I have owned
and built many telescopes over
the years (Maks, SCTs, Newts and refractors) and am an inveterate user
and trader of equipment.
I ran Talscopes (scopes from Novosibirsk – Russia) for 2 years.
I have no affiliations with any manufacturer but have decided
to start writing reviews on the
equipment I have tried so people at least have some feedback on a wider
variety of equipment.
I recently decided that I wanted some sort of spotting scope
to take along with me on my many business trips. It had to be light,
photo-tripod mountable (ie: less than 3lbs), and use standard 1-1/4”
astro accessories as I already had a bucket of eyepieces. It should
also be reasonably good optically and not cost a fortune.
I have a Ranger that I was hoping to push into this role, but
by the time you factor in the weight of the OTA and a tripod rigid to
carry it without undue vibration, it adds up to almost 8lbs… more than
I want to lug around in my suitcase for casual peeks.
Most standard spotting scopes can meet the first two criteria,
but rope you into proprietary zoom eyepieces with a limited power
range. Some of them can accept 1-1/4” EPs, but to get good optical
quality, they can be very pricey.
Enter the Stellarvue SV50. I had read about this baby
refractor/finder online and thought that it sounded like it would meet
my needs. If nothing else, if it failed in the first deployment as
travel scope, it could always fall back to a finder role on my 8”F7
Here are my thoughts and impressions.
General Construction and First Impressions
I bought this used on an on-line astro buy-sell site. It came
in a strong foam lined box with cut-outs for the scope. It came fully
assembled with EP in place. Even though it was used, it looked new.
The SV50 is a 50mm f/4 (200mm FL) refractor using a cemented
achromat doublet for the objective. It is available in a spotter and
finder version. The spotter version differs from the finder version in
as much as it has a ‘clamshell’ mount with threaded holes for camera
tripods in its lower face - the finder version is intended to be
mounted in rings. Also, the spotter version does not have a crosshair
Both spotter and finder types have a smooth integral helical
focuser on the topside of the diagonal that accept standard 1¼”
eyepieces. The SV50’s are RACI versions – ie: right angle/correct image
and the Amici prism diagonal cannot be replaced with other units. The
50mm objective had nice even dark green coatings and is protected from
dew and extraneous light by a fixed dew shield that extends about 2” in
front. The lens cap is a poor fitting thin plastic push-on that tends
to stay in the box when you take out the finder… The gloss black
paintwork and anodizing were flawless.
The clamshell allows the complete body to be rotated and there
is a thumbscrew lock to maintain this position although on my unit, it
was a tight (albeit smooth) movement that would not need locking.
Additionally, the diagonal back also rotates (with another thumbscrew
lock) to provide a convenient viewing position. Why they offer both is
The standard supplied eyepiece is a 23mm of indeterminate
design although it seems to provide about a 50-52° FOV compared with my
other eyepieces of known FOV, which would indicate a plossl design, and
is fully multi coated.
General Use and Optical Performance
The SV50 is light enough that it will not overtax even the
flimsiest of camera tripods, although it is heavier than most 8 to 9x50
finders and could present balance problems at the end of a long OTA.
The SV finder version is lighter at 19oz.
My photo tripod and the SV50 together only weigh 4lbs—not much
more than an extra pair of blue jeans, and fit nicely in my suitcase
for easy portability. The supplied 23mm eyepiece combined with the
200mm f/4 objective throws up a bright, flat 9x image with no evidence
The helical focuser is super smooth and came to focus with all
my standard plossl, orthoscopic and WA eyepieces. I had read somewhere
that barlows would not work in the SV50, so I was pleasantly surprised
to discover that a 2x Russian ‘shorty’ barlow I had in my kit would
work. Perhaps the sloped nosepiece of this barlow allowed it to get
that little bit closer to the focal plane… In any case, it did work and
allowed me the luxury of playing with a wider range of EP combinations
and powers. (Did I mention that I like fiddling with telescopes…?) I
have since found out that my 3 and 5x shorty barlow will also work if
you set the eyepiece out of the diagonal about 1/2”.
Now, I know what all of you are thinking at this point… It’s a
50mm f/4 for God’s sake, what the heck can you expect to do with it…
Well here’s what.
With the standard 23mm EP yielding approx. 9x, the moon came
to a crisp focus with excellent contrast and no evidence of false
colour. Well, duhhh – it’s only 9x Malcolm – everything looks okay at
9x… sooooo, time to pump it up.
In goes a 12.5mm plossl for 18x. Still nice and crisp, good
definition and contrast.
In goes the 2x barlow and 12.5mm plossl for 36x. Okay, the
image is starting to dim as you would expect, but image is still sharp
and contrasty. I can’t go any higher at this point due to lack of lower
FL eyepieces, but I think the SV50 is capable of more.
At 9x, in focus shows some false colour as does in and out of
focus. Vega is a harsh test on any scope and this is after all, a short
focal length achromat, so it is to be expected. However, it seems to be
reasonably well controlled. For reference, a Televue Ranger or your
garden variety 80ED does not show near as much false colour. The star
images in the SV50 are well focused across approx ¾ of the field of
view. (it depends on EP in use – if you ever want to see how eyepiece
designs perform on short and long focal length scopes, I can recommend
the SV50 and any f/10 SCT for a marked contrast… :-)
As I was in the general vicinity, it tried M57 and M13.
Couldn’t pick up M57 from my urban back yard, M13 was clearly visible
as grey smudge – but adequate for a finder. In darker skies, who knows?
What? You expect to see Saturn, I mean Saturn as an extended
image, not just a bright star!, and with a 50mm finder? Well why not?
Using the barlowed 12.5mm (36x), I was able to clearly see the orb and
the edge on rings, as well as Titan hanging off to one side. Clear but
The correct image design makes daytime use a breeze. The views
are very sharp and can take magnification well if you have the right FL
EPs. Chromatic aberration starts creeping in on rooflines and brighter
objects at about 16x – although it is well controlled. At 32x it is
obvious, but not objectionable.
It is interesting to reflect that until the advent of fluorite
and ED glass, this level of chromatic aberration was perfectly
acceptable and to be expected. The only way to minimize it was to make
your scopes in f/12 or f/15 focal ratios. (beware the F15 APO marketing
scams… lol) Modern lens design and coatings have come a long way
towards minimizing the effects of CA – but you can’t beat the laws of
It must be kept in mind that;
- This is a short focal length achromat with a prism
diagonal. This is the worst combination for colour correction.
- This is a finder first and a telescope second.
- CA is really only an issue on bright objects, and at higher
powers. (relative too its 50mm aperture.)
- I’m viewing in light polluted urban conditions. Dark skies
would obviously be better.
- The results were to a certain extent dependent on what
design of EP was in use. Simple EPs like Orthos or Plössls tended to
minimize the CA. More complex wide angle EPs tended to accentuate it …
Overall, the SV50 is a remarkably robust, attractive and good
performing finder/scope compared to the plethora of offshore finders
flooding the market. It exudes the feeling of a quality product that
has not been corner-cut to death in the name of price points and volume
There are a couple of benchmarks in the 50mm finder universe.
One is the Takahashi 7x50mm and the other is the Russian TAL 8x50mm. I
have not had the privilege (or the thickness of wallet) to look thru a
Takahashi finder, but I have looked through a lot of TALs (being the
past N.A TAL dealer), and I can say that the Stellarvue is right up
there with the TAL.
However, unlike those two finders, the SV50 will let you play
with different EPs and powers, and because of its mounting
configurations, is a lot more flexible. It has the ability to be a good
mini telescope for its size and focal ratio, and an excellent 9x50mm
Either way, it is well worth the extra $$.
- Excellent optics
- Excellent build quality
- Smooth focuser
- Accepts standard 1¼” EPs
- Nice user features
- No crosshairs in the spotter version
- Spotter version designed for tripod mounting – hard to
adapt for finderscope use.
- A little on the heavy side.