Collimation, a beginners guide…

Alan Young with his telescope in the 1970s

One of the more interesting parts of running an Astronomical Society is the opportunities that occasionally crop up. We had exactly that last night when we returned to our neighbouring society in Cranbrook (about 25 miles west of Ashford). We hooked up with them earlier in the year.

The Alan Young Telescope in 2010

CADSAS as they are known, are in the fortunate position of having their own observatory based in Cranbrook school. Inside the observatory is a 22.5 inch reflecting telescope originally built in the 1970s by Alan Young. Alan was a race car engineer, so it’s appropriate that the telescope itself is built very much like a race car chassis, and uses Rover V8 valve springs as tensioners for the collimation adjustment!

The Laser Collimater

CADSAS have laboriously been rebuilding the scope since 2005, but had struggled to align the mirrors effectively enough to get a sharp image from the scope. This is an almost impossible job to do manually and the fact they got an image at all is credit to them. We visited the scope for a tour with our society back in March and were able to advise on modifications necessary to allow the mirror to be adjusted.

Delicate adjustments by Ted Pearson (CADSAS Chair)

Last night we went back with some special tools, as the CADSAS folk reported that they’d completed the modifications to the scope. With the aid of a laser collimator (a device for allowing us to see the alignment of the mirrors), a large wrench and a hammer, we were able to adjust the mirrors into correct alignment.

Even better we were able to point briefly at the moon in a the twilight and check the image itself. We were able to see craters and maria on the moon far more clearly. Everyone was extremely pleased with the results.

Myself adjusting the attitude of the primary mirror

This telescope should be easily able to resolve some very deep sky objects visually, and its ability with CCD imaging should be extraordinary.

Next steps will be some more imaging trials, and then extra mechanisation to automate the attitude of the telescope and allow it to be fully controlled remotely.

Can’t wait to have an extended use of the scope in dark conditions!

Category: Astronomy
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