Alt-Alt Telescope Mount I have been designing and building Telescope mounts for decades. All of my prior mounts have been hand built, some were all metal, but others were a combination wood and metal. This as you can imagine is a significant challenge in material selection and time to completion. Around 2012 I became aware that some DIY technologies were becoming available that accelerate the prototype construction for working with engineered plywood. I looked around for some of the systems that were for sale and came across buildyourcnc.com. I was not new to CNC's as I had previously assembled a CNC controller for a Lathe/Mill combo from china that allowed me to build up to medium size aluminum and steel parts. I noticed right from the start that the company (and individual) behind the website had really done their homework on how best to support a “build your own” flat bed router with a high degree of accuracy as well as a high probability that it would work as advertised. I viewed over and over each of the supporting videos and articles about the tips and difficulties of the assembly, and more importantly the computer and SW setups that were critical to getting a home built machine to work. I had been working on a new telescope design, and was looking for a way to sell finished Telescope mounts, but also support the 1000's of Astronomy clubs world wide with a portable, easy to build, design for their medium and large telescope project (every club I was ever a member had a telescope building project! ). For those not into Astronomy, I will make a brief overview of the concept behind building a large aperture wood telescope mount. All other mount designs rely on sensors to measure a mechanical position in reference to their position on the earth, and the time and date. This relationship would be “calibrated” and then the position in the sky would be determined by the sensor output. This usually results in the mount using as much as 80% of the available budget leaving only 20% for the optics. After all, it is the optics that gives the quality of the image, not the mount! My concept is much simpler. A “see in the dark” video camera is mounted on the telescope frame. The mount is simplified to a Joystick design where the mount can move in 2 directions at right angle to each other and point to any part of the sky. A large diameter wheel is place at each end of the axis (x and y) and a stepper motor is mounted with a urethane roller attached to the motor that drives the wheel back and forth(see video). Over the last decade I have developed SW (Drift Imager) that looks though the camera at stars in the sky, figures out which way they are moving and then directs the stepper motors to drive exactly opposite to that motion and track the stars. A second SW (Eye to the Sky) looks at the pattern of stars and generates the position of the mount in RA and DEC(like LAT and LONG on the earth). Now for the fun stuff. After pouring through all of Patrick's videos(the first one's were from his kitchen table) I began to see that he was using the 3D orientation of each part of the kit to keep the router light but strong. I used this approach in the mount. It weighs about 250lbs. A traditional mount could weigh much more than this. It usually has to be massive because no relative motion is allowed after the calibration of the sensors, or the mount will lose it's way in the sky. That's about it. Thank you to Patrick and his team for such a wealth of supporting videos and documentation to what is nothing less than a top notch product! If any of your readers are interested in more information, please access my website. It is still starting up, but I will be posting more information about the telescope mounts there. Very impressive Howard! Keep up the good work.
