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Originally Posted by Reg Johnson
Hi, another new bloke here. Interesting to read all the scope/eyepiece talk. I bought a 12" Dob and am not really over the moon about it (excuse the pun) I saw the article regarding star testing...I see no rings at all under high mag. just a large fuzzy ball. I had the scope outside to cool off for an hour too. Am now dismantling the mirrors as instructed....
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what were your expectations to start with?
I have found that collimation is only the last 5%-10% in sharpness or viewing pleasure
I was blown away with my 10" dob in terms of nebula, galaxies, double stars and planets when i first got it regardless of the collimation.
Friends are dumb struck when they see mars even if it is 10 degrees above the horizon, there is no detail, but to see a red blob, they are wrapped. It is only now 5 months later that I am imaging that i want sharp contrast on planets and splitting stars etc
I would have thought a 12" would still show great amounts of stuff regardless of collimation unless you were expecting to see mars filling up your eyepiece with all the fine detail.
It worries me a bit, because if you are disappointed now, then collimation wont double or triple the experience, it only refines it!
Unless there is something majorly wrong with your scope that is!
Another guy in NSW bought a 12" and was disappointed but that was because he didn't know where to look.
I would love to hear you opinion on Orion (the saucepan in the photo). Point your scope at the handle and let me know what you see. it rises in the east around 9pm my time, so adjust for WA time. This is one of the showpieces of the sky and I hope that the experience of viewing this will get the excitement levels rocketing!!
Re Collimation:
Very important, but not the be all and end all. It is a refining process.
Not sure of the links, but these are my two favourites and in order:
1.
http://www.schlatter.org/Dad/Astronomy/collimate.htm
2.
http://legault.club.fr/collim.html
#2 is for the final tweaking ie a star test.
Especially for the star test, you need your primary mirror less than 1 degree different to the ambient temp. We all say take your scope out and let it cool for an 1hour, but that does not work here in tasmania as the temp keeps dropping from say 9pm to after 12pm. Take a thermometer out with you and check to see when the temp has stabilized and then wait for an hour!!!
Once the mirror is the same temp, then you will see the rings around the outer edge. Of couse as ving has mentioned, the actual atmosphere or high level jet stream could be causing havoc, so that will also bugger the star test!
I am hoping orion will get you excited!