Hi Forge,
I am still new as well. My view on collimation is to align the primary and secondary mirror to achieve a good focus. The lower f number requires more accurate alignment. I use a laser collimation tool as it is easier for me. Just need to ensure the laser is pointing to the middle of the primary mirror and looking from the back of thr scope in the bulleye of the laser collimation tool.
If the alignment is really bad then you wont even get a decent image to focus with the scope.
Due to the dob design, the mirrors will enventually move over time depending on how often and when you move the scope.
Hope it helps.
M11
Quote:
Originally Posted by Forge
Hi all,
I'm very new to this and only just put together a collapsible dobsonian 8. Waiting for a clear sky in Melbourne to give it a go.
I have a question - what is collimation and how often should you do it? From what I've understood it's simply a process of aligning the eyepiece and the primary mirror. Is that correct and do I absolutely need a laser accessory to do it as a beginner (it was suggested to me by someone else)? Also why does it need to be routinely done i.e. why does it go out of alignment after a while?
Thanks
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