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Thread: NexStar 114GT

  1. #1
    Don Scott's Avatar
    Don Scott Guest

    Default 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.


  2. #2
    Stephen Paul's Avatar
    Stephen Paul Guest

    Default NexStar 114GT

    "Don Scott" <dons@linkline.com> wrote in message
    news:3F11FE1D.2090608@linkline.com...

    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



  3. #3
    Michael McCulloch's Avatar
    Michael McCulloch Guest

    Default NexStar 114GT

    "Stephen Paul" <SPaul219@hotmail.com> wrote:


    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

  4. #4
    Mike Wagenbach's Avatar
    Mike Wagenbach Guest

    Default NexStar 114GT

    Don Scott <dons@linkline.com> wrote in message news:<3F11FE1D.2090608@linkline.com>...

    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.

  5. #5
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default NexStar 114GT

    >Get a 6" Discovery Dob with Pyrex mirror. One small step in price,

    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

  6. #6
    Michael McCulloch's Avatar
    Michael McCulloch Guest

    Default NexStar 114GT

    On 16 Jul 2003 23:38:00 -0700, wagen13@yahoo.com (Mike Wagenbach)
    wrote:


    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

 

 

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