Projects In Metal

Startship Part 1

When my daughter Jennifer was about 12 years old, she became interested in Astronomy because of a talk giving by a member of the "The Royal Astronomical Society Of Canada" at her school. In the fall of the following year, she and her friend Danielle became members of the Calgary chapter of the above club. They soon were very involved in the various club activities, including Saturday astronomy classes at the "Science Center".
Before long, being the designated driver, I was taking them to club events around the country. I soon became caught up in the world of astronomy myself, and finally I became a member of the club as well.

While attending the various star parties throughout western Canada and observing the night skies, I became interested in the various homemade telescopes that I saw while attending these star-parties. Finally, I decided that it was time that I build a telescope, and I began doing research in to the various types of telescopes that were out there. After much research, I decided to build a type of telescope known as a "Newtonian Reflector". However, being a machinist, and wanting my telescope to look somewhat different that the typical Newtonian Reflector, I made sketchs for the telescope that you see here.

The first thing you notice about my telescope, is that there is no tube. If my telescope were to be used under the light-polluted Calgary skies, then yes, this is a issue with the image projected by the mirrors being washed out. Under dark skies, there is no issue with low contrast images, due to stray light washing in to the light path. Another requirement for my telescope design was, that 6061-T6 aluminum alloy was to be used throughtout for the construction, other that for some stratigec parts that required more exotic metals.

For the mirrors, I selected high quality mirrors from a small telescope mirror supplier out of California. One of the more interesting features of my telescope is the ring-spider that supports the diagonal mirror. Most people are of the impression that stars have points on them. This is incorrect and in actuality, the star points that you see while looking through a Newtonian Reflector telescope, are actually refraction points caused by the spider that supports the diagonal mirror. If the diagonal mirror support has 2 mounting points, the stars observed through the telescope will have 4 refraction spikes. If the mount has 4 mounting points, the stars will show 8 refraction spikes.

This is true of all "Newtonian Reflectors" from the smallest amateur's telescope, to the largest observing telescope used by profesional observers. In doing my research, I read about a very inovative spider that eliminated these refraction spikes in a "Newtonian Reflector" such as the one that I was building. The spider in question, is a ring design as you see on my telescope. In actuality, the spider is still mounted in the light-path, however the refraction spikes are spread out along the circumferece of the spider, and in effect making the refraction spikes invisible. I used a very thin high-tensile carbon steel for the material in building my spider so that the mirror is well supported.

Another idea I used in the mount for the diagonal mirror, is a ball type mount, typical of a ball mount used in photography. One of the....continued in part 2.....

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