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bauzl
Joined: 22 Aug 2006
Posts: 6
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 Posted: Mon Aug 28, 2006 7:51 pm Post subject: Laser Collimators |
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Hi folks,
I am relatively new to newtonians and collimation as well, of course. But I allready have learned, that I need to collimate after bumping my tube while carrying it to the car or after disassembling it for taking it to vacation - I have a truss dobsionian. In fact, one should at least check in the beginning of every observation session. At least if he uses my scope  An 8" f/6 and maybe I do not dare to tighten the collimation lock screws enough...
So I read several articles in the Net and came to the conclusion that doing collimation does not need any fancy tools. Just a film box that fits in the focuser with a small hole in the center of the bottom should do. And it more or less does - if it is bright daylight and everything can be seen easily.
But at the dark site, things are complicated, because it is dark and nothing can be seen easily.
I think I made some good experiances with a laser collimator. (See http://www.hildenbrandt.com/atm/colum.html for how to build it). This works out really well, even if it is dark - even though it is rumored, that this type of collimation is not really very accurate.
What is your method of choice on site?
clear skies
Bauzl
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There are some dark sites in Austria! |
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Grub
Joined: 09 Aug 2006
Posts: 11
Location: UK
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| Posted: Sat Sep 16, 2006 9:46 pm Post subject: |
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Hey Bauzl
I don't have any great tips for collimating in the field I luckily do quite well from my back garden so I collimate during the day and lift it out carefully a couple of meters. I have however found this interesting solution http://www.olle-eriksson.com/Default.aspx?page=Article&id=117
Might give it a go. |
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astro_nutt
Joined: 26 Sep 2006
Posts: 1
Location: Australia
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| Posted: Sat Sep 30, 2006 12:25 am Post subject: |
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 Hi Bauzl!...Ahhh!..collimating in the field..I try to have it done before dusk using a cheshire cross-hair then fine tune with a laser...but if it does get too dark..using the laser only...I start by shining a red torch down the tube as too ascertain the laser had targetted the centre mark on the primary mirror...then do the adjusts as required..I use an older type laser in which I use a small pocket mirror and hold it alongside the secondary to see if the laser's return beam forms a perfect "donut hole" around the exit port of the laser itself...and that's a good enough...mind you it does pay to check the laser itself at least once a year and it's collimation over a distance of no less than 5 metres..
Cheers!!
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8" and 10" dobs, various home-built mounts, ep's, filters and a wish list! |
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