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  1. #1
    Tim Auton's Avatar
    Tim Auton Guest

    Default What makes a good goto?



    What do you value in a goto system? How do you want it to work? What
    should it do and how should it do it?


    Tim
    --
    I was not a helicopter.

  2. #2
    RichA's Avatar
    RichA Guest

    Default What makes a good goto?

    On Fri, 11 Mar 2005 01:06:32 +0000, Tim Auton
    <tim.auton@uton.groupSexWithoutTheY> wrote:


    The ability with minimal effort to put the target in the field of
    view, consistently. IMO, if when properly set-up it can't put
    an object in a 0.5 deg field, it's not a good goto scope.
    -Rich

  3. #3
    Davoud's Avatar
    Davoud Guest

    Default What makes a good goto?

    Tim Auton:

    What is your purpose in asking this question? How do you think that
    people will answer it? What do *you* think a goto should do?

    Davoud

  4. #4
    Tim Killian's Avatar
    Tim Killian Guest

    Default What makes a good goto?

    Since the OTA is just a passenger (unless it's really long or heavy) in
    most systems, I'll assume your question relates to the performance
    characteristics of the goto mount. My experience with goto includes two
    extremes -- a Celestron GT80 mount for portable use with a small APO
    refractor, and a Paramount ME on a permanent pier. I also frequently use
    a Tak EM-10 GEM without any goto capability because it's portable enough
    to take in the field and can handle heavy OTAs at higher magnifications.
    That said, IMO there is no ideal or perfect goto system, and each has
    strengths and weaknesses. Here's my list of characteristics in order of
    importance:

    1) Reliability, over temperature extremes, loads, voltages, etc.
    2) System stability, no run aways, lock ups, unexpected weirdness
    3) Pointing accuracy - what's the use of a goto if it can't "go to"?
    4) Mechanical stability and load rating
    5) Easy interface to PCs and autoguiders
    6) Service and repair parts, are they available?
    7) Working PEC for longer and/or unguided imaging
    8) Retains alignment between sessions (permanent pier only)
    9) Slew rates over 5 deg/sec are nice to have
    10) Provisions for cables and 3rd-party accessories

    I'm sure others will see different priorities, especially in portable
    systems.



    Tim Auton wrote:



  5. #5
    Brian Tung's Avatar
    Brian Tung Guest

    Default What makes a good goto?

    Tim Auton wrote:

    Here are some commonly listed criteria:

    1. It should point accurately. (Duh.)
    2. It should be reasonably quiet.
    3. It should be reasonably fast.
    4. It should not exhibit significant backlash.
    5. In slewing from point to point, it shouldn't tangle the cords.
    6. Selecting an object to GOTO should be straightforward.

    Brian Tung <brian@isi.edu>
    The Astronomy Corner at http://astro.isi.edu/
    Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
    The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
    My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt

  6. #6
    Mark's Avatar
    Mark Guest

    Default What makes a good goto?

    It should break early and often, forcing you to "GOTO" your star
    charts, learn how to use a finder and get familiar with the sky.

    Mark


    Tim Auton wrote:


  7. #7
    RMOLLISE's Avatar
    RMOLLISE Guest

    Default What makes a good goto?


    Tim Auton wrote:

    Hi Folks:

    I may be wrong, but this sounds suspiciously like some of the weird
    semi-on-topic spam/trolls that seem to floating around Usenet lately.

    If this is a genuine inquiry, my apologize to the poster.

    Peace,
    Rod Mollise
    Author of:_Choosing and Using a Schmidt Cassegrain Telescope_
    http://members.aol.com/RMOLLISE/index.html


  8. #8
    Joe S.'s Avatar
    Joe S. Guest

    Default What makes a good goto?

    It should go to.

    --

    -----

    "Tim Auton" <tim.auton@uton.groupSexWithoutTheY> wrote in message
    news:vlr131lqli4e8jmrn8m252h16nr7etvjua@4ax.com...



  9. #9
    Tim Auton's Avatar
    Tim Auton Guest

    Default What makes a good goto?

    Davoud <star@sky.net> wrote:

    I'm going to make one. I was hoping an open question might give me
    some insight into what people like.

    Judging by the responses, everybody just seems to want something which
    works, rather than something which works a particular way.


    Tim
    --
    I was not a helicopter.

  10. #10
    Mark Gingrich's Avatar
    Mark Gingrich Guest

    Default What makes a good goto?

    Tim Auton wrote:



    As you develop the 'scope-control code, be aware that the customary
    two-star alignment algorithm (for instance, the method described in
    "A New Concept in Computer-Aided Telescopes," by Toshimi Taki, from
    _S&T_, February 1989, pp. 194-196, and in more detail on his website:
    http://www.asahi-net.or.jp/~zs3t-tk/aim/aim.htm) works well, though it
    can be modified to allow even better pointing accuracy by invoking a
    straightforward mathematical tactic. (The specific idea will be
    submitted next month for publication in the _Journal of the British
    Astronomical Association_.)

    It is conceivable that some commercial manufacturers of Go To 'scopes
    or digital setting circles have already implemented the very same
    trick. If so, they've kept it a trade secret until now. (Since I'm
    not privy to their source code, I honestly don't know if any existing
    products take advantage of the idea.) However, if it turns out the
    concept hasn't yet been realized, then the good news is, once the
    manufacturers become cognizant of it, their existing products can be
    made to achieve better pointing accuracy with just a firmware update.
    In other words, the improved accuracy results without having to expend
    additional effort at calibration time, nor must one upgrade to
    higher-precision encoders.

    --
    ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
    Mark Gingrich grinch@rahul.net San Leandro, California

 

 
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