Take the listed Cave 10-inch f/5 Dobsonian. Yes, he has virtually every name brand scope, mount, eyepiece and more, but he has some seriously out there stuff as well. When you go to his website, trust me you will be overwhelmed by what is available. The reason I am writing today is because when I ran across Don Rothman’s site, Astro Parts Outlet Used Telescopes, I realized that any ambitions I might have as a trader were dwarfed by Don’s pre-owned astro-tech offerings. In fact, I should have been born in another century, traveling the Trans-Saharan Trade Route from North Africa to West Africa with a caravan of camels trading ostrich feathers, salt, gold and more (you’ll have to Google it to see what I mean).īut I digress. If you are interested in used telescope equipment, we keep an ongoing list of equipment available on our website here.*** *** Editors Note: Since the publication of this article, Astro Parts Outlet Used Telescope has suspended its operations. The motor is bolted to the sprung section.Ah used telescope stuff! I have always enjoyed finding a deal – boats, cars, jewelry (for my significant other of course), and yes, telescopes – well you name it, I am into getting a deal. This picture shows the worm gear itself - mounted between two bronze bushes and spring loaded against the worm wheel. The motor output shaft runs through the middle of this block supported by a bearing at one and and a bronze bush at the other end. This insert can be bolted to the worm gear block on the mount, and it has a thread onto which I can screw the Meade DS motor. I have made an anodised red round aluminium insert. The second picture here shows a breakdown of the parts. The first picture here shows the motor on the RA axis attached to the mount. The images below show the parts I have made to connect my Meade Autostar DS motors to my telescope mount. Unless both the motor output shaft and the worm gear are properly mounted with bearings and bushes, there is a chance of things bending and flexing - resulting in serious tracking errors at the telescope end.įor example, if the distance between the worm gear and motor output shaft on my mount changes about a millimetre during the course of one rotation, that translates into several tens of arc seconds error in tracking - an unnessecary cause of periodic error. The key to a successful implementation of DS motors on a telescope mount comes down to ensuring both the worm gear and motor shaft are rigidly fixed with respect to each other. I use timing pulleys and belts as they are easier to tension and get correctly adjusted than toothed gears. It is much neater and more effective to use gears or timing belts/pulleys to transfer the drive from the motor output shaft to the worm gear. One option is to directly couple the motor output shaft to the worm gear - however, this is rather unstable and impractical. The worm gear, which is usually 10-20mm in diameter needs to be driven by the motor output shaft. Most mounts are driven using a worm gear that turns a large worm wheel. The real trick is mounting the motors properly on your homemade telescope mount. The added benefit: Once you've told Autostar about your mount, all the GOTO and autoguiding features will also work. It is up to the motor controller (the handset) to calculate the correct motor speed, and the joy of the Autostar 497 controller is that you can effectively tell it the size of your worm wheel reduction - meaning the motors can be used to run more or less any mount. A large worm gear means the motor must go faster to keep up with the sky than with a small worm gear. Depending on the various tooth counts and ratios of the worm gears, you have adjust the motor speed specific to your setup.

This converts the fast electric motor to a the very slow speed / high torque drive requirements of a telescope mount. Secondly, it is possible to adjust the speed settings in the Autostar 497 controller.Īll telescope mounts have large reduction gears external to the motor gearbox - usually a worm-wheel and gear arrangement. First, it is physically quite straighfoward to engineer something to fix the motors onto any type of DIY mount.

There are two major advantages to the Meade DS motors. The power requirement is 12v (I use a PC power supply) and the handset is the Autostar 497 controller - the same one I use on my LXD55 mount. There is a central plug board into which you connect the two motors, the power and the handset. The system consists of two black plastic motor boxes containing the electric motor, various electronics, and a reduction gearbox. Meade Telescopes did a great service to us crazy astronomers who like to build their own mounts when they produced the Autostar DS motors.

Meade telescope motor drive