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  1. #1
    Stephen Paul's Avatar
    Stephen Paul Guest

    Default Meade 12.5" Starfinder (mini-review)



    The following is a short review of the used Meade 12.5" Starfinder Donsonian
    that I purchased over the weekend. The bottom line here is that I would
    highly recommend this scope to anyone looking for a low cost entry into 12"
    and larger apertures.

    Mike Fitterman and I evaluated the Starfinder 12.5" Dobsonian last night and
    it gets a definite thumbs up for optical quality and light grasp. The
    addtional 2.5" of mirror diameter compared to my XT10 definitely brings out
    more detail in faint fuzzies, as well as improving the brightness of objects
    such as the planetary nebula in M46 (which, by the way, looked simply
    awesome). We were under good skies for the region, at roughly magnitude 5.2.
    The Winter Milky Way was just discernable overhead, M44 was an easy naked
    eye object. All four corner stars in the Little Dipper, as well as all the
    handle stars were also visble. That's really just a rough estimate since I
    didn't take the time to do any counts. (I was having too much fun looking in
    the eyepiece).

    The seeing didn't allow a serious evaluation of wave front error using a
    star test, but from what I _could_ see, I have no qualms claiming near 1/8th
    wave, toward 1/6th. Given better conditions though, I'm guessing we'd have
    seen 1/8th or better. Certainly we had some moments of excellent clarity
    with very fine detail visible on Jupiter at 300x. It was the boring side of
    the planet, but momentarily the polar region would split clearly into belts
    and zones, and details were visible in the SEB and NEB. The separations in
    the polar region are not something in memory using the XT10. That's not to
    say it hasn't happened, just that it wasn't as memorable.

    The previous owner had swapped out the original altitude bearing pads with
    magic sliders, and added an Orion-like Correct Tension system (springs that
    assist gravity), and that's all the mods he made. The rest of the system is
    stock as far as I can tell.

    One thing this scope _really_ needs, is a new focuser, and badly. With the
    point of this scope being aperture on the cheap, I'll probably go for the
    $99 Orion all metal 2" rack and pinion focuser that Martin Howell suggested
    (as opposed to the more expensive super high quality options (Moonlite,
    FeatherTouch, JMI, ...etc.)). I'll also do the standard upgrades to the
    stock rocker/base (Teflon pads and EbonyStar) to improve the "stiction", and
    general motion for high power tracking, but for powers up to 200x or so,
    using 65 degree or larger AFOV eyepieces, the stock motions were acceptable.

    In time, if this scope turns out to be "one that I'll keep forever", the
    mirror set might find it's way into an AtroSystems Telekit for travel to
    distant sites, but for now, for local use here and there and in the
    backyard, the solid tube is prefectly workable. On the other hand, if this
    becomes a permanent backyard fixture instead I will probably consider the
    e2scopes base upgrade, and one of the aforementioned expensive focusers.

    Be that as it may, the stock ground board could use some better feet on it
    to get the center bolt out of the dirt. What's on there now is nothing more
    than three rubber bumper blocks that simply don't provide enough height. I'm
    not sure where these came from, but I suspect the original owner, and I'm
    guessing that there weren't any included from the factory. Since three
    points make a plane, I'll be adding three of something. In keeping with "on
    the cheap", 1"x1" pressure treated blocks, rated for ground contact
    probably.

    The mirror cell is a piece of particle board and the primary is stuck on
    with adhesive. I was concerned about this, but the fact is that I put the
    scope out early enough that by the time we got out there and got serious,
    the thing had cooled just fine. I spent the first 30 minutes or so messing
    around with the secondary position anyway, so it wasn't time lost. I like to
    store my scopes outside in a shed to keep them close to ambient, but right
    now I'm stuck with keeping them in an attached garage. That means a
    differential of around 20 degrees, and that seems to take a little over an h
    our to equilibrate. In the meantime, I don't really foresee swapping this
    out for an aftermarket aluminum cell. At least not for a while. Here again,
    if I do, I'll probably go with something inexpensive like the University
    Optics.

    At F4.8, the OTA is 58" long. Add 6 inches or so for it's stance in the
    base, and subtract a few inches for the position of the focuser, and you get
    a zenith eyepiece height somewhere around 5' 2". I'm 5'7" (to the top of my
    head, not at my eyes <g>), and as far as I'm concerned, this is the perfect
    size solid tube Dob for someone of my stature who wants to stand flat foot
    at zenith. Any larger in aperture, at F4.8, and the zenith eyepiece height
    would demand a stepping block.

    At 55 pounds, the OTA is reasonably easy for me to get on and off the rocker
    by myself, although I use my hand truck to move the OTA out to the backyard
    from the garage. At 25 pounds, I just grabbed the base by the handles,
    hoisted it up over my head, and let the altitude bearing cutouts come to
    rest on my shoulders. Very effective, and very easy to carry for extended
    distances.

    Using Nagler T6's and Pentax XW's, coma at F4.8 was definitely visible. In
    these wide field eyepieces this became quite evident in the outer regions of
    the field of view. Mike had, to his own surprise, mentioned pin cushion when
    using the Pentax XWs, but later on, in the Nagler T6's I noticed that the
    edges were suffering some not so well understood aberations compared to the
    F5 w/Paracorr views in the XT10. I will need some more eyepiece time and a
    new focuser that will let me use the 2" Visual Paracorr before a verdict can
    be reached. Currently I suspect that Mike was seeing more coma than he is
    accustomed to with his OA6.5, but I'll let Mike give his own opinion on
    that.

    Price used:
    $750 (that's on the high side too, shop around)

    Expected addtional expense:
    $99 + S&H for a more usefule focuser.
    $50 or so for base bearing upgrades (Teflon pads/EbonyStar)

    Total: ~$900

    Not bad at all for a 12.5" aperture scope with a focal length of 1525mm.

    --
    -Stephen Paul



  2. #2
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default Meade 12.5" Starfinder (mini-review)

    Stephen:

    Nice review. Sounds much like my experience when I purchased my used 12.5 inch
    Discovery DOB which had had a JMI two speed which the seller had replaced (for
    some unknown reason <g>) with a modified Meade Model 77....

    On the way home, I stopped at OPT and bought a JMI RCF 2 inch focuser,
    definitely worthwhile. You can buy it as a kit for about $80 but I am not sure
    if it is available in the length necessary for the Meade..

    Also, I replaced the particle board mirror cell with a UO mirror cell, not the
    best but it knocked about 8 lbs or so off the weight which meant redoing the
    base which you will probably want to do anyway at sometime. Ebonystar and
    Teflon do work a whole lot better than magic sliders...

    Anyway, sounds like you got a winner...

    Oh yeah, one other thing, is that new scope a DOB or an SCT... <G>

    Best wishes and have fun...

    jon

  3. #3
    Stephen Paul's Avatar
    Stephen Paul Guest

    Default Meade 12.5" Starfinder (mini-review)


    "Jon Isaacs" <jonisaacs@aol.com> wrote in message
    news:20040224145833.12281.00000300@mb-m02.aol.com...

    Thanks.


    Apparently, according to my spelling skills of late, it's a "Don"-sonian,
    which phoenetically sounds very close to the Massachusetts spelling
    "Darn"-sonian. <VBG>



  4. #4
    WJShaheen's Avatar
    WJShaheen Guest

    Default Meade 12.5" Starfinder (mini-review)

    Thanks for a terrific review. This is the sort of stuff that s.a.a. is
    _really_ all about.

    Bill in Cave Creek, AZ




  5. #5
    Chris Nicholl's Avatar
    Chris Nicholl Guest

    Default Meade 12.5" Starfinder (mini-review)

    Stephen Paul wrote in message:

    Nice review, Stephen. This is a scope I've been keeping my eye on,
    for the time when I move up from my XT8. I've always heard that the
    mirrors are remarkably good, and so buying one used and slowly
    upgrading it is a great way to leg into some better aperture at a
    reasonable cost.


    One other to consider is Orion's even-cheaper $39 model. That's what
    I put on my XT8 when I swapped out the 1.25" focuser. My plan was to
    upgrade that eventually, but I've been so happy with it that I really
    don't feel the need. It's the best bargain out there (at least, that
    I'm aware of).

    Enjoy the new scope - got it just in time for the faint fuzzy season,
    I see!

    Chris Nicholl

  6. #6
    Rich McMahon's Avatar
    Rich McMahon Guest

    Default Meade 12.5" Starfinder (mini-review)

    Stephen

    Great review and congradulations on getting the 12.5 starfinder.
    Have alot of fun with it.

    Rich


    On Tue, 24 Feb 2004 16:10:00 GMT, "Stephen Paul"
    <SPaul219@hotmail.com> wrote:



  7. #7
    Jon Isaacs's Avatar
    Jon Isaacs Guest

    Default Meade 12.5" Starfinder (mini-review)

    >


    Those are pretty nice focusers, but they have limited travel and they are much
    lower profile than the Meade. Those Meades take a special focuser.

    I have been impressed with the accuracy of the placement of the
    focusers/mirrors on those Asian DOBs. It seems they have everything engineered
    to the point where they can get by with less travel and still handle just about
    any eyepiece out there.

    jon

  8. #8
    Martin R. Howell's Avatar
    Martin R. Howell Guest

    Default Meade 12.5" Starfinder (mini-review)

    Stephen,

    Here is an interesting link for Starfinder owners:

    http://www.roboticobservatory.com/jeff/meade/two.htm


    It contains some interesting upgrades (along with photographs) for the OTA.

    ---
    Martin
    Remove "ilikestars" from email address



  9. #9
    Stephen Paul's Avatar
    Stephen Paul Guest

    Default Meade 12.5" Starfinder (mini-review)

    "Chris Nicholl" <chris_in_mass@yahoo.com> wrote in message
    news:4c3c3b39.0402250449.33ef107@posting.google.co m...

    the
    the

    I think that's the same one that comes with the XT10 (GS).

    I now have the "Precision" all metal focuser installed (nope, I didn't waste
    any time) and it is extremely rigid and _long_. When it's racked out all the
    way, it's something like 6.5" from the OTA to the top of the focuser, and
    still doesn't have even a hint of flexure!! The focuser is 3.5" high, with a
    5" draw tube. When focused with the Paracorr and a Plossl, it appears to be
    racked out about 0.75". With the Paracorr and a Nagler T6 it's racked out
    further, and without the Paracorr it's racked out further still. I'm going
    to get some measurements on this and post more accurate data later (maybe
    tonight/tomorrow).

    I think when they decided to market this as "precision", hey meant the
    rigidity and not in the ability to focus. That's not to say that focus is
    any more difficult than with any other focuser without a micro-fine
    adjustment. I also don't see any barrel adjustments to eliminate the
    non-existent "wobble". The XT10 focuser on the other hand, has some wobble
    that needs to be adjusted out.

    Verdict: the Orion 2" all metal precision focuser is one solid hunk of
    metal. The focus motion is smooth, and although a bit stiff, has _no_
    flexure. I've backed off the screws that hold the focusing shaft in place
    and that has relieved some of the stiffness of motion. I do wonder if this
    needs the "Chinese greese" removal treatment, but in the meantime, I'm going
    to continue to use it as is for a while, and see how it goes.

    -Stephen


  10. #10
    Martin R. Howell's Avatar
    Martin R. Howell Guest

    Default Meade 12.5" Starfinder (mini-review)


    Stephen Paul wrote:



    Stephen,

    Did you have to enlarge the hole in the Starfinder's tube to accommodate the
    new focuser and, if so, by how much?

    Regards,


    Martin



 

 
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