Our Telescopes

I built a Dobsonian telescope in 2001, when I was getting back into astronomy. In October 2007 I bought a 16 inch Meade Lightbridge. I've not had a chance to do a direct comparison of the two telescopes as yet, but hope to in the near future. Many of the modifications that I've already made to the Meade are based on my experience with the 10 inch telescope. You can read about the Meade Lightbridge modifications here.

Our 10 inch Dobsonian Telescope

Having sold my old 4.5" Tasco reflector (which I bought back in '84) I decided that I wanted something with a little more light gathering power, but which would be just as simple to move around, and not cost too much to buy/build. After casting around for ideas, I eventually decided on a Dobsonian mount for the telescope: it would be reasonably easy to build, portable, and also quite secure when stored - something that was important with two very inquisitive youngsters at hand :-)

I regularly used a Celestron C8 back in the late 70s, when I was at Teachers College, and I remember that back then Alt/Az mounts were looked on as toys by most people in the science department. It took a little while for me to overcome this prejudice when looking at options for building a telescope now, but is seems that more people are building Alt/Az designs than Equatorial mounts - John Dobson's design, and the many variations, has revolutionised amatuer telescope making over the past 20 years.

This telescope uses a 10" F5 mirror, 3/4" ply construction, and 20mm aluminium trusses.
The design is largely from Kriege and Berry, with a lot of ideas and inspiration from with web and the ATM mailing list.

I use a 1 1/4" focusser and a Rigel Systems Quickfinder. The mirrors, spider, focusser and some lenses came from Binocular and Telescope Shop , while a few other bits and pieces came from Adelaide Optical Centre. I found both great to deal with, and the advice they offered was invaluable.

Trusses are fixed by 4 wingnuts at the secondary cage, and another 4 wingnuts at the primary box.
The trusses are covered by bicycle handlebar foam that I had left over from making dual control kite handles.

The covering in the secondary cage is made from the Ebony Star left over from making the Alt/Az bearing surfaces. Setting circles are fixed for Alt, and adjustable for Azimuth.

Altitude is pretty good, but there is a need to reset the Azimuth by selecting a known object if I move more than 90 degrees from where I was successfully reading Azimuth settings. I use the Planetarium software on my Palm IIIc to find Alt/Az info for the objects I'm looking for - particularly Messier objects that are just too faint to be seen with the naked eye in a big city (well, big for Australia). This software is absolutely fantastic! I don't even bother taking my star charts outside now - the Palm Pilot with the Planetarium software is all I need.

Packed up and ready to go... It fits in the back of our station wagon and leaves enough room left over for all the paraphenalia a family with two young kids takes away for a long weekend.

There is actually quite a bit of room between the bottom of the primary cell box and the bottom of the rocker box., so the blue box of eyepieces, gloves and other bits and pieces can fit securely in there, or I can put the two boxes in separately if I want a lower profile in the back of the car.

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