Collimating a Dob

I had a quick look using the search function here and although there are
quite a few references to tools for collimation I couldn't find anything on
how to collimate a Dob.

I have the basic idea.
I'd just like a more detailed sort of walk-through.

Cheers.

Despite there being lots of threads here (I tried the serach too), some of those will just refer the user to a website. Try your luck there?

You can do it by eye, basically what you need to do is make sure that the secondary is perfectly centred as seen through the eyepiece holder. You use the tilt screws on the secondary for this.

Then you adjust the screws on the primary to get that centred, when finished the spider+secondary should be perfectly centred, it takes a fair amount of trial and error to get used to doing it but after a while, you'll become a master, or get a laser collimator, it'll add years onto your life. :lol:
We can use the 2" laser I have here for this, we'd figure out a way of getting onto that 1.25" focuser.

In the past I have used a salt dispenser for centering, you know the type, they are silver with a small central hole, and it fitted the 1.25 focuser perfectly, this way your eye is centred while collimating, this is very important.

Hey Frank,

I found this flash tutorial good when I got my Newt. In fact, he's got a load of good stuff there now.

www.andysshotglass.com/Collimating.html

Trev

Hi Frank,
I found this a bit tricky aswell at the start, so in the end I just went on ebay and bought a 1.25” laser collimator for about 25 euro. Now it takes me all of a minute or two to collimate my 12” Lightbridge. You put the laser into the eyepiece hole and then tighten or loosen the screws on the diagonal mirror until it is pointing to the middle. The Lightbridge has a reflective dot in the centre of its mirror which is great.

In other words, if you are lazy like me, get a laser collimator and it will keep you sane for longer

Best of luck