Quote:
Originally Posted by barx1963
Pete
If that is the advice being given by a retailer they need to be named. Pm me with it uncomfortable doing it publicly.
Collimation has nothing to do with the finder, it is about aligning the mirrors within the scope to optimise the light gathering potential and minimise aberrations by ensuring the coma free portion of the image plane.
Star tests can be used to collimate a scope, a good explanation can be found here http://www.garyseronik.com/?q=node/238 and on the same website a bit of an explanation of collimation generally is here http://www.garyseronik.com/?q=node/169 , read the FAQS at the end as they make the purpose of collimation very clear. Also be aware that the no tools collimation can be a little hard to execute on a non driven dob (but not impossible) and usually needs good seeing. I usually use a star test to confirm my collimation.
Now for this question "can perfect concentric star circles confirm DSOs and other objects will be seen and in focus?". If collimation is not quite perfect, the scope will still be usable, it might not be optimal, but collimation is a game of diminishing returns. Your 8" f6 as a "slow" is quite tolerant of small collimation errors, so best advice is collimate it as best you can then get out and use the scope, rather than spending hours trying to get it perfect.
Malcolm |
Ok I will PM the retailer, I was relayed from the prevous owner how he was told to align to a distant object (tree branch) and use finder scope confimation (I know there is alot more to it) I have found a vitiamin capsule lid that may fit instead of film canister.
Also some links I will post later for easier colilmation, ,but once I read some links makes it very easy to understand.
And don't let collimating put you off a dobsonian, it's easier than first thought.