is it easy to learn how to colminate a telescope by yourself or easier to have

[Astro]

someone show you ?
i have a newtonian dobsonian

[katekebo]

Newtonians are relatively easy to collimate, providing that you are careful, have the right tools and proceed with caution and patience (go in little steps). Cassegrains should be collimated by a professional (or somebody very experienced). It's ALWAYS easier if somebody shows you how to do it, but there are several decent on-line tutorials.

When it comes to collimating refractors (apos), there are probably less then 20 people in this country who know how to do it (and have the right equipment).

[cosmo]

Yes, it very much depends on what kind of telescope. Newtonians are easy.

A Newtonian in a dobsonian mount is straightforward. There are only two degrees of freedom that need adjustment (the x and y tilts of the mirror) and those are not too critical.

[Boatman1]

Have someone show you one time-- not very hard to do.