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RE: [Meade-Uncensored] north north or north?

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  • Christopher Erickson
    Polaris is less than one degree from true North and works excellent for all GOTO scopes when used in the Northern hemisphere. If your viewing location doesn t
    Message 1 of 9 , May 1, 2002
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      Polaris is less than one degree from true North and works excellent for all
      GOTO scopes when used in the Northern hemisphere.

      If your viewing location doesn't give you a clear view of Polaris, you can
      use a magnetic compass and your local deviation value, which can be computed
      from a local map or from here:

      http://www.geolab.nrcan.gc.ca/geomag/e_magdec.html

      http://www.geolab.nrcan.gc.ca/geomag/e_cgrf.html#MIRP

      -Christopher Erickson
      Network Design Engineer
      We Byte
      5432 E. Northern Lights Blvd., Suite 529
      Anchorage, AK 99508
      N61° 11.710' W149° 46.723'
      www.data-plumber.com


      -----Original Message-----
      From: william mccarthy [mailto:willymac1@...]
      Sent: Tuesday, April 30, 2002 1:05 AM
      To: Meade-Uncensored@yahoogroups.com; Meade-Uncensored@yahoogroups.com
      Subject: RE: [Meade-Uncensored] north north or north?


      Use a proper magnetic compass to find magnetic north, then adjust using the
      magnetic variation which you can get
      from a map of your area, which I suspect is also available on the web
      somewhere.
      It's also about 1degree to the left of Polaris if that's accurate enough
      for you.
      Bill



      At 01:05 30/04/2002 -0700, David Page wrote:

      >In reference to the "north" position for GOTO scopes:
      >
      >Magnetic north
      >Celestial north?
      >or "true" north?
      >
      >Which is it?
      >If true north, how do I find it?
      >
      >
      >
      >David Page
      >
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    • steve_robbins13
      You ll never point your telescope accurately enough using a compass. Granted, it will be better than nothing. Also, keep in mind that magnetic variation
      Message 2 of 9 , May 7, 2002
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        You'll never point your telescope accurately enough using a compass.
        Granted, it will be better than nothing. Also, keep in mind that
        magnetic variation changes constantly, and must be updated from year
        to year on the charts that are referenced. Yes, the magnetic pole is
        in motion, as if we didn't need additional complication.

        The celestial pole is only 1º to the left of Polaris at a single
        instant each day, as the celestial sphere rotates. There are fancy
        alignment scopes that give you the correct orientation of the
        celestial pole in relation to Polaris and have a second off-center
        crosshair for Polaris. Of course, to use it properly, you must know
        the correct local astronomical time (not the same as the time on your
        watch, which is an average time for a 15º longitude range.) More
        complication. Isn't this fun?

        In practice, Polaris works fine. Can't see Polaris? Move to where you
        can, or your alignment will be poor at best. Not worried about
        photography? Just do a two star alignment with the scope anywhere
        near alignment (less than 10º off is fine, and that is only so the
        scope can kind of track equatorially) and GOTO will work just fine.
        Your object may drift out of the field of view during tracking.

        Philosopher of Phaint Phuzzies
        Steve Robbins
        DeLand, FL
        St Petersburg Astronomy Club
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