View Full Version here: : Had dob for 2 yrs, never collimated
28-05-2012, 09:59 PM
I have had my dobsonian now for 2+ yrs.. And have not yet collimated... Just wondering if this is normal.. The image still looks fine? I think?
It's making me paranoid cuz I keep reading threads on here about how you should collimate all the time.. Admittedly I don't take out my scope that much.
Am I doing something weird..? Thanks!
28-05-2012, 10:33 PM
Hi. Firstly, if you are happy with the views, that is good, but good collimation will usually improve the view. Mind you there are limits that are largely dependant upon the size and speed of the scope.
I have a 5.25" f7 newt that gives pretty much the same views when a bit out of alignment as when I have spent some time getting it just right.
A smaller/slower scope is more tolerant than a larger/faster one.
Having said that it is a good habit to get into to check the cillimation each time you use the scope. That way you know you are getting the best view possible.
29-05-2012, 09:23 AM
Collimation is like fine tuning a car's engine - you can get away without it, but the performance is crappy. And to be honest, I don't always tune my Newtonians either, but I wouldn't let it go on for more than one session without a quick check.
It can also be a bit tricky to figure out how to actually align the optics, which is all that collimation is, just with a fancy word. The process for me is now routine, takes no more than 5 minutes tops, and the rewards are staggering.
As Malcom says, some reflectors are more tolerant of this misalignment than others. Also if the scope is a solid tube it is less prone to big changes than a truss/collapsable tube. But all benefit from a tweek.
You don't need fancy gear to do it either. Have a look at this link on how to collimate your reflector (http://www.skyandtelescope.com/howto/diy/3306876.html). It goes through the process without the use of fancy gear, and explains well the role of both the secondary and primary mirrors in the alignment process.
If you are unsure on how to do it, I'd be happy to show you as I see you are in Sydney too. It isn't difficult, and having someone show you takes out a lot of the guess work. Drop me a PM is you are interested.
29-05-2012, 09:21 PM
Ah... Awesome! Thanks - I'm going to have a go this weekend before the Venus transit... Been avoiding it all this time, I guess because I'm afraid to screw it up and make it worse! Haha.. Thanks for all the pointers!!! :)
Take a look here at this wonderful little video tutorial performed by the staff of Orion Telescopes, on how to collimate a dob.
Hope it helps.;)
30-05-2012, 08:21 PM
:) Cool as Alex and Mel and Suzie say's falling out of collumation is like the graduale blindness , and out of tune cars ( that we all own) and its not noticed , but happens .
One thing :D Msshh , you are a real amateaur astronomer , using a scope ( 2 yrs ) , and looking after her so well . cudos , to you my friend .
I love and respect my scope as well .:thumbsup: .
30-05-2012, 08:39 PM
I'm interested to know what the particulars of your scope are Msshhhh. What do you have?
30-05-2012, 09:09 PM
:shrug:Gotta be an 8 inch Newtonion ..? Awsome scope .
Can you imagine a 200mm refractor ??
30-05-2012, 09:24 PM
I think I need more sleep. I couldn't see where the size was mentioned previously lol. Back to bed for me...
31-05-2012, 06:57 AM
Haha... Im afraid its only a 6''...its a baby!
Thanks everyone.. Looking forward to getting my hands dirty now ... Haha ;D
03-06-2012, 08:00 AM
;) Only ? Woaw !! don't put your self down there mate , 6 inches is a lot of light ,, :question: especially when my most used scope is only 70mm ,, something like 2.78 inches :lol: , awsome little Pronto she is .
05-06-2012, 03:11 PM
Ok. So I did the collimation star test... and all the rings lined up perfectly when the star was unfocused. I have to therefore conclude that the scope is still perfectly collimated.. weird weird weird..!
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