focus and collimation made simpler

Backyard Voyager

Telescope focus and collimation issues

Mars Watch 2007

While not nearly as close as its 2003 swing by our planet, Mars will still be in great positions for viewing this year. Opposition will be on December 24th, Christmas Eve.

8/10/2007

Mars on 8/10/2007

Diameter (arcsec) 7.37

Apparent Magnitude .45

Celestial South Pole at top

Mars on 10/10/2007 10/10/2007

Diameter (arcsec) 10.36

Apparent Magnitude -.230

Celestial South Pole at top

Mars on 11/10/2007 11/10/2007

Diameter (arcsec) 13.130

Apparent Magnitude -.830

Mars at opposition 2007 12/24/2007

Diameter (arcsec) 15.78

Apparent Magnitude -1.630

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Making a Single-Piece Crayford Focuser by Jim Sapp

One of the more troublesome aspects of building telescopes can be coming up with a design for a suitable focuser. The simple sliding-tube type is always an easy solution, but can be very tedious when changing eyepieces or trying to achieve a critical focus with a high power eyepiece.

The simple helical design can be made with a very low profile, and is easy to construct with off-the-shelf plumbing parts if you don't mind having the eyepiece or camera rotate when focusing or having a very limited smooth-working travel.

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Thoughts on Autocollimation by Nils Olof Carlin

I have long had a feeling that the existing descriptions of the autocollimator and its mode of operation have not been based on a clear understanding. This analysis attempts to describe the reflections seen and their positions as functions of miscollimation and builds on a discussion in the Yahoo Collimate_Your_Telescope forum.

The autocollimator is a flat mirror mounted in a short tube made to fit a Newtonian telescope focuser, and set accurately perpendicular to the

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Newtonian Collimation FAQ by Nils Olof Carlin

Well, maybe the questions here are not as frequently asked as they ought to be. After all, a lot of amateur astronomers own and/or use Newtonian telescopes. If you are one of us, you should ask these questions, and find out for yourself how important the answers are to the performance of your instrument.

Collimating a telescope is lining up its optical components (lenses, mirrors, prisms, eyepieces) in their proper positions.

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Collimating your Telescope by Chris Icough

Collimation is at first a daunting task, and many new users are afraid to do it. I was also like this at the beginning, but after doing it a few times, I have learned a really good trick. First of all I would suggest getting a set of ‘Bobs Knobs' or equivalent. These are thumbscrews rather than allen screws and are a good investment. If by mistake in the dark you miss the screw and leave a fingerprint on the corrector plate then that is infinitely better than missing with an allen key and scratching the corrector.

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Collimating a Newtonian Tal-2M and an LX200 SCT by Jan Timmermans

When I compared my astro images with those captured by others while using comparable telescopes I began to fear that something was wrong with the collimation of my TAL-2M. So I captured a star-out-of-focus image and submitted it to the QCUIAG community. I know the image below lacks lots of quality, but it clearly shows that I did not have the required perfectly round "do-nut" image I had seen at Thierry Legault's site.

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Improvements for your GSO Focuser by Pollux Chung

Everyone was thrilled when GSO released a dual-speed Crayford focuser at half the price of the models offered by the two most well-known producers of third party focusers. At that price there were a couple of problems, but, as Pollux Chung points out, they are not at all insurmountable problems. I this tutorial he shows how to eliminate the "stickiness" reported by numerous owners. Following these easy steps can produce the sort of smooth motion for which those other models are so well known.

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