I'm looking for a design for a light-weight Dob mount for my 8" Newt OTA. I've seen a few examples on various sites, but I thought I might throw it out there to see if anyone has come across some innovative design.
It normally fits on an EQ5C mount, but I would sometimes like the convenience of a Dob when just simply having a look around.
Thanks for the links, they are very useful. However, your 10" compact truss design is brilliant - elegeant, simple and functional. I had already considered purchasing 10" optics for a Dob, rather than than removing the 8" optics from my existing tube. I've been impressed with the truss designs I've seen so far - yours has inspired me!
Thanks for that mental4astro - nice one! Two truss rods? I guess if they're mounted deeply enough in the mirror box, then they would be quite secure/stable? No problems with collimation?
Mate, she holds collimation really, really well. The poles are set down all the way down near the mirror cell mount, and at the secondary they pretty much run half the length of the board. The black disc you see in the photo is a light baffle.
I made everything you see other than the optics & focuser. It isn't hard to make if you are handy with power tools, at least a mate with a circular saw & router is an advantage for accuracy. I mate helped me in this department.
I took the design from a book 'Making & enjoying telescopes' by Miller & Willson.
I happened to stumble on the original designer of the two pole concept, a U.S. navy sailor based on an Aircraft Carrier. He was the ship's photographer with an intrest in astronomy. The limited space available to store items compelled him to come up with the two pole design, using a 4.5" mirror, I think it was f/4.5. Here is the Aussie connection, he ordered the scopes optics from the states, but the delivery address was in Perth a his ship was to stop there during a stint at sea.
I've seen this idea taken to an extreme with a few 17.5" scopes. Some now being made commercially in this size.
Mental
Thanks for that. I'm really spoiled for choice when it comes to these nice simple designs now. I'm pretty handy with the tools and I have a good collection for the job, so I don't think it would be too difficult to come up with something that would do very nicely. Thanks for the reference, too - I found a cheap second-hand copy on Amazon.
I have the book you mention Alexander and have found it really useful. A scope called Alice by R. Ravneberg is also featured in the stickies on the cloudy nights ATM forum.
Nice scopes by the way and thanks for the links tnott
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