Why Is My Zhumell Dobsonian's Laser Collimator Missing the Secondary Mirror?

  • Thread starter NerfMonkey
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    collimation
In summary, the speaker is having difficulty collimating their 12" Zhumell Dobsonian telescope. They have tried using a laser collimator, but the beam is not hitting the secondary mirror and the image through the eyepiece holder is not clear. They are frustrated and seeking help. After adjusting the primary mirror using the laser, the issue is resolved.
  • #1
NerfMonkey
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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

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.
 
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  • #2
looks to me like you just need to adjust the primary mirror.
 
  • #3
I tried collimating it with the laser and I think that was the problem. Now it's perfect, thanks!
 

1. What does "collimating" mean in regards to a telescope?

Collimating a telescope refers to the process of aligning its optical elements (mirrors or lenses) so that light passing through them is properly directed towards the eyepiece. This ensures clear and sharp images when viewing through the telescope.

2. How do I know if my 12" Zhumell Dobsonian needs collimation?

If your telescope is producing blurry or distorted images, it may be a sign that it needs collimation. Additionally, if you notice that the secondary mirror is not centered in the eyepiece or that the reflection of the primary mirror is not centered in the secondary mirror, it is likely that your telescope needs collimation.

3. What tools do I need to collimate a 12" Zhumell Dobsonian telescope?

To collimate a 12" Zhumell Dobsonian telescope, you will need a collimation cap, a Cheshire eyepiece, and a laser collimator. These tools can help you align the primary and secondary mirrors and ensure that they are properly centered.

4. Can I collimate my 12" Zhumell Dobsonian telescope on my own?

Yes, you can collimate your 12" Zhumell Dobsonian telescope on your own. However, it is recommended that you have some basic knowledge of how telescopes work and follow the manufacturer's instructions carefully. If you are unsure, it is always best to seek help from an experienced astronomer or optician.

5. How often should I collimate my 12" Zhumell Dobsonian telescope?

The frequency of collimation depends on how often you use your telescope and how frequently it is moved. As a general rule, it is recommended to collimate your telescope every few months or whenever you notice a decrease in image quality. It is also a good idea to check the collimation after transporting the telescope to a new location.

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