NexStar 114GT

I inherited a cheap hand-me-down scope (department store type) and have
used it for a few years and have enjoyed it a lot. I am now considering
buying my first real scope. What are your opinions of the Clestraon
NexStar 114GT. Say anything you want, but please be honest.

"Don Scott" wrote in message
...
I inherited a cheap hand-me-down scope (department store type) and have
used it for a few years and have enjoyed it a lot. I am now considering
buying my first real scope. What are your opinions of the Clestraon
NexStar 114GT. Say anything you want, but please be honest.

Some thoughts:
The Nexstar 114 is a 4.5" reflector with a lens in the system that
effectively increases the focal length, while allowing the tube to be kept
short. In general these have not been accepted as a preferable optical
design. They are not strictly a simple Newtonian design, but a hybrid of
questionable quality and useability.

The Nexstar 80 is built around the ubiquitous Synta 80mm F5 achromat, and
will provide wide fields of view (roughly 4 degrees with a 32mm Plossl).
This is equvilant in field of view to a binocular, with the advantage of
variable magnifications, using the eyepieces of your choosing. As an
achromat, there will however be chromatic aberation, which generally
speaking is a separation of white light into its component parts as in a
prism (but to a _much_ lesser degree). For example, at 80x and above,
Jupiter has a distinct violet haze in and around the edges. I have a Synta
80f5 that is not on a GoTo mount and it gets used quite often. (This scope
is the only one of the little Nexstars that I would recommend to anyone, but
first you must understand its limited usefulness based on aperture and
chromatic aberation).

The Nexstar 4 is a 102mm Maksutov-Cassegrain that is generally considered to
have mediocre optics. Spherical aberation, or the inability of all light
rays to come to focus at the same point, can be somewhat of a problem for
these scopes resulting in soft images at magnifications above 140x. Maks
also have the problem of requiring a longer time to reach thermal
equilibrium than other designs. In particular, this is a somewhat serious
problem for a scope that is intended to be plopped down in the backyard on a
moments notice. To compensate, depending on the temperature difference
between inside and outside, one night have to place the scope outside up to
an hour before expected use before images are as sharp as possible. (I have
the Tasco clone of this scope, and it sees little use, since my 80f5
compares to it handily).

The Nexstar 5 is built around the Celestron 5" Schmidt-Cassegrain which is
an optically superior scope to any of those previously listed. Not only so,
but this model is on a different class of GoTo mount, which has much better
tracking capabilities than its smaller siblings. This is really what I would
consider the smallest of "serious" general purpose telescopes. The 5"
aperture has sufficient resolution to begin to show individual stars in
globular clusters, has enough light grasp to show the cores of brighter
galaxies with some hint of their whispy halos, and with a standard SCT focal
reducer/corrector can provide a reasonably wide field of view. (I also have
the 5" SCT on non-GoTo mount).

The Nexstar 8 is a most serious instrument for the visual observer, and from
their they simply get better and better as far as capabilities. (I don't
have one of these, but I do have a non-GoTo 8" SCT on a fork mount).

Having said all of that, in most cases, the important thing about buying a
telescope is aperture. Aside from those scopes that I indicated I owned
above, I also have a 10" Dobsonian which is by far the most used telescope I
own. I keep it in a shed outdoors and roll it out with a handtruck. (I use
the handtruck just so I can keep the base and tube together as one unit, but
it is hardly necessary).

In my opinion, unless you can afford the Nexstar 5 or Nexstar 8, you are
better off spending your budget on a non-GoTo scope with an aperture of at
least 6". An 8" F6 Dobsonian can be had for roughly $350. You will need to
learn to find stuff on your own, but when you find it, it will look oh, so
much more spectacular, than it will in the 5" and smaller telescopes.

Best wishes,
Stephen Paul

"Stephen Paul" wrote:

I've since removed the OTA for use with a Unistar Light mount from Universal
Astronomics, but for a time I used it this way. I really didn't like the
noise from the motors, so I've sort of given up on the N4 mount. At 1AM the
sound gets pretty damned annoying.

Is the Nexstar GT mount noisy? What about the N5/N8 mount?

The 60/80GT is noisy too. I've never heard the N4, but the GT
definitely makes some noise when slewing in altitude and the tracking
'purring' sounds are a little intrusive.

I have a 3 year old N8, and it is considerably quieter when slewing
and tracking. I can tolerate it all night. ;-)

---
Michael

Don Scott wrote in message ...
I inherited a cheap hand-me-down scope (department store type) and have
used it for a few years and have enjoyed it a lot. I am now considering
buying my first real scope. What are your opinions of the Clestraon
NexStar 114GT. Say anything you want, but please be honest.

Someone, probably Ed Ting, wrote that you should not get a GOTO scope
that costs less than $1000 (or something like that). Probably true.
By the same token, ANY budget comes down to a tradeoff between cost of
the mount and cost of the optics, suggesting a Dob unless you must do
photography.

I started with a Nexstar 80 and a StarMax 127 (really 121) 1.5 years
ago. The Nexstar is still on its second set of batteries, which shows
how much it gets used.

I found the GOTO wasn't very accurate, whether inherently or because I
wasn't able to align it well. Things I should have been able to see
didn't always wind up in the field, and it seems that if you pan
around to search, it stops tracking the motion of the earth,
eliminating the value of a motorized mount! This may have been fixed
by software updates, which you could probably learn on the Yahoo Baby
Nexstar group.

I thought I would be able to hang the 127 on the Nexstar with a Baader
adapter, but the mount is so small and light, I was too scared that it
would tip over. The 80GT mount could probably support the StarMax 102
this way, so if you are dying to have cheap GOTO and want a wide field
and higher mag/color free system, that might be the way to go.

Pointing the 127 was a bit of a pain until I added a red dot finder
(spend the extra $15 on a real Telrad or Rigel) and upgraded the
finder to a 9 x 50. Properly equipped, starhopping is kinda fun, if
you're not in a big hurry every night. The big finder is not only a
huge asset in starhopping under light pollution, but it is a pretty
fair rich-field scope for big, bright things like M31, M45, Kemble's
Cascade, etc. (I can't remember ever trying NGC7000 with it.)

Other than narrow FOV, the mak's biggest weakness was the shaky mount.
It's now available on a steel tripod mount, which should help. I
bought the 100 f/6 refractor on that mount, thinking I would put the
mak on it and the refractor on the old mount, but I like the refractor
enough that I'm planning to ship the SM and its original mount to my
SO's parents house for use when visiting them.

Finally, I got a 6" Discovery dob to see if I liked Dobs. The azimuth
motion is not great, but the optics kill all my other scopes.
Diffraction spikes are a bit unlovely, but unless you can afford a big
APO, this is the way to go. The lack of an RA drive is sometimes
annoying, but overall, it's the stablest mount.

Get a 6" Discovery Dob with Pyrex mirror. One small step in price,
one giant leap in performance. Or get an 8". Two small steps in
price, and all the scope you'll probably really ever need.

Get a 6" Discovery Dob with Pyrex mirror. One small step in price,
one giant leap in performance. Or get an 8". Two small steps in
price, and all the scope you'll probably really ever need.

Hardin is still selling their 8 inch DOB for $299 plus shipping. THat is a
deal that it is pretty hard to beat. Comes with a 2 inch focuser and a 8x50
finder.

jon isaacs

On 16 Jul 2003 23:38:00 -0700, (Mike Wagenbach)
wrote:

...it seems that if you pan
around to search, it stops tracking the motion of the earth,
eliminating the value of a motorized mount!

This is not the case. All Nexstar scopes keep tracking. The accuracy
of the tracking is another story, but it is not affected by panning.

---
Michael McCulloch