Brought myself a gift from a business-trip,
a Nexstar 4GT. Having all the Autostar telescopes, I somehow wanted a
Nexstar to compare. Many folks on the internet are quiet enthusiastic
about the mechanical quality of even the cheapest Nexstar scope. Why
the N4GT Maksutov? Hmm, quiet easy to explain, it appears to be the
most portable scope of the Nexstar range, at least what packing
volume is concerned; yet Maks are usually rather heavy, so is the
N4GT. When I bought it, the same night I had a look to Jupiter. It
was not all so straight forward, as I had to buy a whole bunch of
batteries before, hard to locate if you're not willing to spend a
fortune on disposal items of this kind. Anyway, I was pleased with
the function, so far at least. Belts on Jupiter were nicely visible,
moons too. First collimation tests on stars (don't ask me which) were
showing OK collimation (could certainly be better).
The scope was
provided with a 20mm “SMA” eyepiece.
Returning home some more sky and a bigger variety of eyepieces were at hand. In particular eyepieces with a shorter focal length. Going for 4mm (Super Plössl), the optics of the N4GT were still keeping up, in contrast to the tracking. Yes, this sturdy mechanics, everybody likes apparently are guiding the telescope nicely over the sky, but just not in the correct speed. I know, this only can be a matter of the electronics of the goto scope, but on the other hand, what's a good goto scope w/o good goto controlling electronics?! OK, somehow I was expecting this, as some folks on the internet reported on problems as such on Nexstar controllers. When I find time, I will try to investigate on the electronics a littler close. Maybe there is some clock-frequency tuning fix-up, maybe the oscillator crystal is off... To be seen.
Alignment appears to be somewhat tricky. Not always the controller accepts the stars where they really are. For what ever reasons some star combination (suggested by the controller) never led to successful alignment, hmmmm, scratch my head... Sometimes alignment works instantaneously. BUT, no matter what led to alignment finally, the scope never is tracked in the right speed. Never!
Something which appears to be a feature is a little disturbing at first sight, the way that goto approaches a target. Always from left side, always from below (when I remember correctly), no matter what you do. Slight corrections also result in this, thereby making it impossible to decently hand-guide, e.g. for piggy back photography. So, forget about that!
For me, the N4GT is an easy to transport
“visual fun” telescope. BTW, motors are not really
silent, taking the N4GT to an hotel on a resort, you should not
insist having the most quiet room, if you understand what I'm
intending to say; the motors and gears really release some noise
(just as ETX-70 and ETX-90).
The N4GT requires to be
equipped with batteries (or external 12V). There is no way to operate
this scope by hand, this would ruin the clutches of the Nexstar
mechanics. External 12V brings me to another point I really disliked,
the power cord connects to a part of the base that rotates about the
azimuth axis, causing “wire-wrap”; whatever is lighter
(more mobile), the scope of the power supply, will move first...
The future purpose of the scope is found to
be my contribution to planet parties of my local astronomy club.
Brighter than the EXT-90 and definitely easier to transport than the
ETX-125 the N4GT found it's place in my collections, it certainly
missed the first place though. There is one thing I really love about
the scope, the way the hand-box is taken care of, really really
nice!
Last modified Feb. 6th 2005