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Collimation Problems

  1. Dec 31, 2007 #1
    I have a 12" Zhumell Dobsonian and I've been trying all day to collimate it and can't get it lined up right.

    This is what it looks like when peering into the eyepiece holder:
    http://img184.imageshack.us/img184/4786/christmasscope008dx6.jpg [Broken]

    Can anyone tell me if this is a secondary mirror or primary mirror problem? I see all of the primary mirror and the spider is almost dead center, so it can't be that horribly misaligned, but when I put the laser collimator in the holder the beam completely misses the secondary mirror and hits the wall.

    I'm really getting frustrated because it shouldn't be this hard. Can anyone help?

    Thanks in advance.

    EDIT: I used the laser collimator and adjusted the mirrors until the beam came back and hit the target area on the collimator and when I looked in the end of the tube (just for a second!) the beam was smack in the middle of the primary mirror, but now when looking through the eyepiece holder the image looks even worse than before. I don't really have anything around to focus on since it's nighttime and the scope is indoors, so I can't test it that way. But it seems to me that the image you see when looking in the holder should be close to perfect when the laser beam comes back and hits the target on the collimator.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Jan 1, 2008 #2
    looks to me like you just need to adjust the primary mirror.
  4. Jan 1, 2008 #3
    I tried collimating it with the laser and I think that was the problem. Now it's perfect, thanks!
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