advice on laser collimator

[bntwillis]

I am interested in hearing input on the type of laser collimator you would purchase for an 8" dobsonian. I have tried to collimate manually but this has not been the best and I fear I make things worse rather than better. I am in the states, and when I buy I will be doing so online as I live far removed from any type of shop that may carry this type of device.

Thanks,

Bob

[triton1]

Hi,I bought a cheap one which I use on my sw200p reflector.You will have to make sure that the collimator is collimated.To do this rotate it in the focuser and the dot should remain in the same place.If not there are three screws on it for adjustment.Once set up very easy to collimated I do it every time I use my scope.

hope this helps Jonn

[LeeB]

Its easier to collimate the laser if you use a v block and observe the dot from 20 feet or so,then use the screws to correct( only tiny turns at a time)  the error is more obvious and doesn't rely on the focus tube which is normally a little slack.

[g0ibi]

2" Hotech, brilliant, expensive but very accuarate and easy to use 

Cheers

Ron

[Scott]

That's the beauty of a cheshire collimation tool....The collimator requires no collimation .

However, if it's a laser you require, make sure that it has the ability to be collimated itself. 

TBH I use both

[ScottS]

I use this one. Due to it's shape it will sit nicely in a V block and is easily collimated with the three screws at the base. Mine was miles out when I received it but 2 mins of tweaking and all was well. Only really good for collimating the primary though.

http://www.scopesnskies.com/prod/GSO/Revelation/nla111/g2laser/collimator.html

[Charic]

bntwillis.........Supposedly the laser is more accurate (but only if the device is callibrated itself) I use the Next Generation laser, which needed collimation after purchase ( one of the three screws didnt seem to adjust? It unscrews and comes out or screws in to a point then continues to rotate without tightening [must be mis-threaded]  but i was able to get the laser spot dead centre at over 9 feet away) I will use the laser with a Barlow (my barlow has plastic lens, need a better quality one) because I cant reach the adjusters and view at the same time. I use a 35mm film cannister with a 1mm hole, and get very good collimation if someone else makes the primary adjustments, whilst I observe through the cap. I get a perfect centre spot reflection on the inside of the cap. With laser on its own, the spot is so small, that I find I keep adjusting to try and get dead centre, but the adjusters are so sensitive on the primary, as are the locking bolts? it actuall takes longer to complete the task. So for me, 35mm cap to adjust, and laser for field use only.
auspom says` make sure the laser is capable of being user collimated. The adjusters on mine were hidden behind black silicon rubber, which you have to dig out, which may invalidate your warranty?