Bob's Astro Site
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Bob's Astro Site
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| Secondary Thumb Screws.
My Obsession 20 is of the older type that did came with Phillips screws for secondary mirror adjustment. I soon realized that this was going to be a hassle, every time I set up it seemed that a small tweaking of the secondary was necessary. Not wanting to replace the secondary holder completely I decided to just replace the adjustment screws with thumb screws. Nowhere could I find 4" long 8-32 thumbscrews. Home Depot did have 8-32 all-thread rod in up to 6" lengths at around 43 cents each and plastic 8-32 knobs for just over $1.00 each. The steel tubing I used is just steel brake line tubing that I had lying around from other projects.
There are a number of ways to extend 8-32 screws, I chose to just use all thread rod and sleeve them with the steel tubing to give lateral stability. To construct the extensions I welded 8-32 washers on the ends of three 3" pieces of steel tubing. Then cut the all-thread rod into 4-1/4" lengths. 3" for the extensions + 1" normal length of secondary screws+ the 1/4" that the knobs need = 4-1/4". All that is left it to replace the old secondary screws with the extended screws.
Third Wheel Transporter.The Second thing I did to the Obsession was to build a set of handles that were more comfortable to transport the scope with. Some of the sites I use require manual transport of the scope about 1/2 mile. The old wheel barrow style handles were tiring after a 1/2 mile push each way. I came up with a high handle design with a quickly attached 3rd wheel that would require only pushing the scope and not have to lift it at the same time. The high handles also allows not having to remove the handles if scope is loaded in a short bed pickup that had a tool bos. The handles project out and over the tailgate.
The Third wheel mechanism is quickly attached by sliding the third wheel bracket over the ends of the side frames. The inserting two pins.
Wheel shown attached but in rest position. In this position the scope is resting fully on the ground board. The side frames nor the third wheel are supporting the scope and can easily be removed.
To place scope in the ride position you only need to lift up on the handles and take a step forward and let back off the handles. The third wheel being offset towards the rear lets gravity hold it into the ride position. In ride position the scope is now suspended on the three wheels. To move the scope you need only to push forward on the handles, no lifting is required. To get the scope out of ride position you only need to lift up on the handles and roll the scope back a few inches. The third wheel will fold back down.
Scope and components read to cruse to dark site, |
