Quote:
Originally Posted by troppo
Hello. I would like some advice on purchasing a laser 1.25" collimator. They seem to vary in price, so what is the good or bad with some of these. I have a 300mm Newtonian telescope f4.5. Focal length 1500mm.
Thank you.
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Hi,
A tough subject with different views.
(pun)
The basic unit is a tube with an ordinary "pen" laser in it. They can go out of alignment themselves and give you false results, so you might get one with 3 adjustment grubscrews on it which can correct this. For example
Guan Sheng deluxe Newtonian laser collimator...A$59.00
http://www.andrewscom.com.au/images/...collimator.jpg[/IMG]
TypePrice $(AUD)Laser collimator - Deluxe Newtonianreturn beam type. Latest version. Has half-silvered 45° mirror target for easy primary mirror collimation.
Only $59.00
Then the next level up would have maybe a bit better laser unit, more stable construction and a 45 degree target window
https://www.bintelshop.com.au/Product.aspx?ID=8108
Some of them have a variable power laser for day or night use, and a safety factor
http://www.aoe.com.au/telescopemaintenance.html
Now all these have an issue, which is possible slop between the barrel of the laser housing and the focuser body. So there is a type to cope with that (this looks a very good unit BTW)
http://www.hotechusa.com/collimator.html
The question of whether the laser beam is coming out of the collimation tool in the right way is worth considering. There are sealed units which are more likely to be reliable, that is, you should not need to adjust the laser beam yourself:
http://www.astrosystems.biz/laser.htm
Now, there are different ways to use a laser collimation tool, which fall into 2 broad categories
- collimating the primary mirror by centering the return beam in the laser unit
- collimating the primary mirror by using a barlow lens with the laser collimation unit
It would bloat this post to go further here, but read up on
http://www.collimator.com/coltext.htm#newton
http://web.telia.com/~u41105032/koll...tm#barlowlaser
Hope this assists