Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Recommended Posts

Hello everyone, 

As a farely new member and astronomer, I've decided to seek help for collimation. 

The task seems pretty daunting at first but I think I got the basics down. 

Unfortunately I cannot find any answers for the questions I have, so here it is: Is it 'normal' to see the focuser's end? 

As you can see in the attached picture (poor quality, let me know if I should do another) we can see a rectangle at the left, the focuser.

I don't think I should be seeing this and I don't know what causes the problem since the secondary 'seems' to be aligned and the doughnut is dead center. 

I'm using a XT10 and the focuser is all the way in. 

Thanks for your precious time, 




Edited by AntoineDemangeat

Share this post

Link to post
Share on other sites

Short answer: Yes, - for newtonian scopes only.

A bit more on procedure, - do it all way Out if it hides one of the primary mirror holders (in your case, it will not, as it has 4 holders)

The best option, focus, lock the focuser, and collimate at this point if possible.

P.S. do you use for visual or AP?

asking, as my 130PDS has a focusing pint quite deep way in with my ASI1600MM and Canon, and focuser's tube casted a nasty shadow on the primary,

which caused D shaped stars.

if you use it for visual, - not a problem at all, - it will not have any impact.

Share this post

Link to post
Share on other sites

Hello, thanks for your reply! 

I'm using it for visual observations only. Thanks for letting me know, I knew it would have disappeared if I put the focuser out if the way but was intrigued nonetheless! 

Can you develop this a bit more for me :

26 minutes ago, RolandKol said:

The best option, focus, lock the focuser, and collimate at this point if possible.

Do you mean I should find a target first, focus it and then collimate the scope? If yes, what kind of target do you mean? 

Thanks again! 

Edited by AntoineDemangeat

Share this post

Link to post
Share on other sites

If you use it for visual,

no much difference to be honest, as super good collimation has benefits for photography only (during long exposures)

In your case, simply during next observing session you can mark your focus with the mostly used EP 

and next time  collimate while focuser is at the focus point. Once done, check the result with full in and full out.

if focuser is good, you probably will not see any difference


Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Zermelo
      150mm F/5 Newt, as received new, view down eyecap collimator (no adjustments attempted by me):

      I've read a couple of intro guides, so I'm led to believe that the off centre image of the secondary in the primary is normal for a fast reflector.
      The whole image of the primary in the secondary seems to be reasonably central too.
      My concern is obviously that the black dot from the collimation cap is not within the "doughnut" centre marking from the primary.
      I've tried here to superimpose a circle with centre lines, but I'm not sure if I've got the circle itself correctly positioned (I'm not sure what I should be lining it up against):

      Now, the interesting thing is that it's one of those jobbies with a sealed, non-collimatable primary. But I believe the secondary has all the usual degrees of movement.
      Does it look likely to be far out?
      I can try a star test tonight (first time for that too).
    • By Corpze
      So, I have been testing three different kind of lasers, each one is supposed to be the "best" in each category or what you want to call it, the hotech and HG is almost the same, but whit the difference in how you lock it down.
      The Catseye is very different in how it works.

      I made a Youtube video of my thoughts


      What do you think? which one do you use?

      Regards, Daniel


    • By Corpze
      Hi, I am trying to collimate my astrpgraph, a TS N-AG10 with a Hotech 2" self centering laser and I am having some questions of the clamping procedure.
      Each time i am trying to tighten the collar so that the laser would tighten up in the focuser, the laser dot is quite far off the earlier spot the laser hit.

      I have sience bought a Howie Glatter 2" laser, when i adjust the secondary so that the laser dot hit exactly in the center of the primary dot and change laser to the hotech, the laser dot is about 4-5mm off, if I release the Hotech laser and re-tighten it, the dot will hit somewhere else.

      I can not just trust the hotech laser - has anyone else experienced the same thing?

      *Both of the lasers is collimated itself at 5 meters distance with the dots not moving at all.

    • By LordSaladMan
      I'll begin this post by saying, I've searched every forum.  I've tried every tip.  And I'm hoping you beautiful people can provide some suggestions based on my specific issue.  Because, as my title states, I'm just about ready to give up.  Here's a bit of background before I list the many ways I've tried to resolve the issue.
      I own a Celestron NextStar 8SE and a Canon Rebel T6.  After many nights of trying, I cannot get a clear image of planets, or even the moon.  I've given it plenty of time to reach thermal equilibrium each night (1-2 hours).  When viewing through the eyepiece, the image is an absolute blur.  When viewing from the camera, I get no image at all.
      Here are the things I've tried on the telescope itself:
      Focusing the telescope via the "Focus Knob" Collimating the mirror via the 3 screws Using a Duncan Mask to make collimation easier. Focusing the telescope on an object much closer, getting a clear, sharp image through the eyepiece and the DSLR, then attempting to view a star. Waiting for, and viewing during, a near-perfect clear night with very little atmospheric turbulence. I live on the westcoast of the US.  So, the only objects I'm able to see clearly (with the naked eye) are the moon and Venus.  I cannot describe the level of disappointment and frustration I feel when I can't clearly view them from the scope.  Venus is as bright as ever, and I'm getting a blur.  I tried using the DSLR and the planet doesn't show up at all.  Just black skies.  My DSLR settings are as follows:
      Manual Focus Shutter Speed: Bulb ISO: 1600 What am I missing?  I feel like I've tried everything and I just want to throw up my hands in defeat.
    • By Simple-Human
      Hi, Just wondering whether collimation is necessary on a smaller Telescope like mine (https://www.astroshop.eu/telescopes/skywatcher-telescope-n-76-700-astrolux-az-1/p,5010#tab_bar_1_select)? If so, how often do you need to do it, and how do you know when it needs doing? Any other tips on how to do it are welcome. 
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.