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| I think I could best be described as an
armchair astronomer who has accidentally acquired a certain amount of
hardware, although I did enjoy making my first 6" mirror. Skinflint is
also a fair description, as is shown by this picture of the 6"
Dobsonian assembly |
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| More recently, I acquired a 12" f4 blank which
had reached the figuring stage before someone dropped it and took a big
chip out of the back. Figuring and testing this filled in several happy
hours, and it then went into a skeleton frame after aluminising. |
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| Attempting some webcam photography indicated a
rethink of some aspects, like the motor drive ratios on the alt-az
mounting, the rigidity of the finder, and the fact that with the tiny
field
of view in a Philips TouCam, one really needed some sort of equatorial
drive, since the images were crossing the field too fast for comfort. |
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| Since the drive had to be reasonably portable,
I decided on an equatorial table. Chunks of an old wardrobe were
pressed into service, along with odd bits of wood and contiboard, some
8mm screwed rod, and a 240v synchronous motor bought originally for the
6" when it did possess an equatorial mount. The baseboard of the
Dobsonian mount simply sits on the table framework. For visual work,
the improvement in comfort is wonderful, and webcam work with short
exposures is perfectly feasible. Note the meccano gears - nearly 100
years old. |
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| I then proceeded to re-invent the original
sidewalk telescope and got a four foot long cardboard concrete-form
tube from a firm who were sufficiently intrigued to let me have less
than a lorry-load. This is now assembled and painted and ready for when
the skies clear and the weather gets warmer. |
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