Laser Collimators

I need help in deciding which laser collimator to get for my soon to arrive 14" f-5 dob. Have heard that a barlowed laser is the way to go for f-5 and under. Please help.

Sam

Howie's are among the best:
http://www.collimator.com/coltext.htm

Hi Sam
Getting good collimation can be done many different ways using active or passive types tools. I used the cheshire and always had issues or sometimes doubt that I had good collimation. I tried the barlowed laser method and collimation became much easier for me. I highly suggest you get 2" tools of your choice. I can personally vouch for the Catseye tools and the Howie Glatter tools. I've settled on the Telcat cheshire/sitetube combo and Infinity autocollimator from Catseye and the 1.25"/2" laser and barlow attachment from Howie Glatter. I check with the sitetube to set the secondary so it is nice and round and centered. Then I use the laser with single beam to aim the secondary so the laser dot is on the primary center mark. Then I install the barlow attachment and aim the primary so the shadow of the secondary is centered around the hole in the target face. Then check with the autocollimator and make any final adjustments (usally not) and thats it. All this assumes the scope is correctly set up in the first place.
Hope this helps
Buck

Sam Nothman said:

I need help in deciding which laser collimator to get for my soon to arrive 14" f-5 dob. Have heard that a barlowed laser is the way to go for f-5 and under. Please help.

Sam

Sam:

I see you have gotten some folks recommending the Howie Glatter laser collimators. Well... I am another one who has been extremely satisfied with the Howie Glatter collimators. It's been close to 9 years since I bought my first one and it served me well until a year or so ago when I accidentally dropped it about 6 feet on the concrete garage floor.

Oh it still worked fine but it was slightly out of collimation, not as bad as a stock Asian collimator and it's dot was still a tight airy disk like image but still out of Howie's tolerances, 15 arc-seconds or 1mm at 45 feet... 8O One of these days I will send it back to be recollimated.

During those 8 years I used it for a variety of scopes, my main scope was a 12.5 inch F/4.06 so it got a lot of use. I use an Orion Cheshire for the secondary rotation, the laser for the secondary tilt and the barlowed laser for the primary tilt...

Anyway, I decided it was time for a new 2 inch collimator so I talked to Howie and went for the 635nm job, it works better in the bright of day, I bought the holographic attachment, the Blug and the barlowed laser attachment. It came with the aperture stop standard. It does the same accurate job my original collimator does but it is considerably easier to use since it doesn't require using a barlow and an attachment.

The Blug is nice but not all focusers remain small enough to use the blug, if your focuser steps up to a larger than 2 inch diameter tube then the blug may not work, at least that is my experience.

The standard 1.25 inch/2 inch with the barlow attachment is a good solid choice... works for me.

I do not recommend spending your money on an Asian made collimator. The ones I have seen have been out of collimation and the reports are that even when you learn to collimate them, they do not remain collimated long. They also produce an irregular blob rather than a nice circular spot...

The way I look at it is this: Might as well buy the good one to start with, it's cheaper than buying the poor quality one and then upgrading...

Howie machines the collimators himself in his home, he's a one man show...



Jon

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