Results 1 to 2 of 2
  1. #1
    mattodell's Avatar
    mattodell is offline Junior Member
    Points: 7,264, Level: 59
    Level completed: 57%, Points required for next Level: 86
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement1000 Days+ Registered Achievement!
    Join Date
    Feb 2009
    Location
    Dover, United Kingdom
    Posts
    12
    Points
    7,264
    Level
    59
    Thanks
    2
    Thanked 2x 2 Posts

    Default etx-125 alignment



    Hello all,

    Many thanks for your welcome messages on the introductions page.

    I've been practicing getting the ETX-125pe set up indoors (due to cloudy conditions) so im not stumbling around out in the dark.

    would somebody be able to explain polar alignment to me and whether its worth setting the scope up this way? ive read a few articles on it now but im still confused!

    brighter skies out there today, so fingers crossed i may get out tonight! i'll keep you posted if i do.

  2. #2
    blackchihuahua's Avatar
    blackchihuahua is offline White Dwarf
    Points: 7,443, Level: 60
    Level completed: 47%, Points required for next Level: 107
    Overall activity: 0%
    Achievements:
    10 Days registered365 Days+ Registered Achievement!750 Days+ Registered Achievement!First 1000 Experience Points1000 Days+ Registered Achievement!
    Join Date
    Jan 2009
    Posts
    49
    Points
    7,443
    Level
    60
    Thanks
    0
    Thanked 29x 14 Posts

    Default

    The ETX125 mount is a basic fork mount. If you just set it flat on a table or mount it flat on a tripod, it functions as an alt-az mount.

    Tilting the scope, such that the center of the azimuth axis points toward Polaris (N Hemisphere) polar aligns the scope. The alt axis (rotating the forks) then tracks in Right Ascension and the mount becomes the functional equivalent of a German Equatorial Mount (GEM).

    The easiest way to do this is to rotate the OTA such that it points straight up
    (90 degrees on the setting circle if the circle is correct). Then tilt the scope until Polaris is centered in the field of view. The amount of tilt will depend on your latitude. Be sure that the control panel on the scope base is facing West (again for Northern Hemisphere).

    As an aside, a GEM is basically an alt-az mount with the ability to easily tilt the Az axis. It looks complex and intimidating but is quite simple when analyzed.

    Polar alignment (IMHO) of an ETX works best if you're not using Goto, that is as a manual scope. Once you find the target, the motors take over and track the object which makes for much easier viewing. Don't forget to set the scope to polar mode or remove the appropriate screw from the hand controller to allow it to default to polar mode.

    My ETX90 is mounted on a tripod with an equatorial wedge which tilts it to 40 degrees (for my latitude). All I have to do to set it up for manual viewing with tracking is carry it outside and orient it such that the axis of the OTA points roughly toward Polaris and I'm all set. Takes a couple of minutes.
    The more precisely you level the scope and the more accurately you point it toward Polaris, the more accurate your tracking will be. High precision is not necessary for most manual viewing, however.

    Good Luck

    Ken

 

 

Similar Threads

  1. Alignment for the 6SE
    By tech11165 in forum Celestron NexStar Telescope Forum
    Replies: 7
    Last Post: 01-06-2011, 02:51 PM
  2. Alignment
    By cdnpilot in forum Meade LX200 Telescope Forum
    Replies: 13
    Last Post: 07-29-2010, 02:25 AM
  3. GPS Alignment
    By Magician's Apprentice in forum General Astronomy Forum
    Replies: 1
    Last Post: 07-04-2004, 09:29 AM
  4. Alignment tip
    By Joe S. in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 08-07-2003, 04:57 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 02:52 PM.