hi Charles,
you might want to take a look at the URL below and see if it suits your needs. they offer kits with almost everything you need to build your own mount. the links are given near the top of the webpage.
all you need to add is some standard piping which you can buy from your local hardware store. i believe the instructions are clear on the size and length of pipes to buy.
http://www.petersonengineering.com/sky/
hope that helps.