Nils, Very familiar with microcontrollers - I use Microchip products a lot. http://www.microchip.com/ For anyone that is interested... Their application notes...
I continue to see references to a Rule-Of-Thumb that suggests that the diameter of the sector on a polar drive should be no less than the aperture of the...
Mark, There are more ways than one to skin a cat. The Arduino has some nice features - PIC type controllers have others, I am sure, though I have no personal...
Although there is a mechanical requirement for robustness that relates to the weight of the OTA, there is also a higher precision requirement that becomes...
Thank you Al! While my suspicions regarding mass properties and moments of inertia were well founded, I failed to consider the obvious need for greater ...
Nils, There are indeed many ways to skin the cat. The Microchip environment is much the same as what you described: You get a proto board with a USB interface...
I'm not sure you should tie this strictly to aperture. Perhaps a greater consideration is focal length although in most case greater aperture equates to ...
Mark Whitaker <tnut55@...> wrote: " I'm not sure you should tie this strictly to aperture." I understood what you wrote Mark which, given my limitations in...
Mark, what you are saying is correct for the case you describe, IMHO. You imply that resolution at the focal plane is limited by the sensor or film and greater...
Art, Since you asked about periodic error... To take a stab at periodic error: Any error (out of roundness, bearing noise, transverse error in the alignment of...
Hi Mark! I appreciate the amount of effort you put into this response. It validates what I suspected about the worm's contibution to PE and alerted me to the...
The saga of my 20 inch F/5 continues, with some good news and some questions: Good news is that the flexure I was observing with my 3 carbon tubes design was...
Hi Benoit! Judging from one photo, it appears that the CG of the OTA is down close to the primary mirror. Thus far I only remember seeing one or two photos of...
I realize that my previous mail was ambiguous. What I mean is that flexures/vibration are not caused by flexure in the OTA, but are a limiting factor of the...
... <snip> ... <snip> ... Benoit -- the mounting of a large scope can quickly become the limiting factor to the size of an amateur instrument. ;) I am trying...
Benoit, If you are past the limit of what the mount can handle, and this is a relative thing, there are only two expedients that come to mind. First is the old...
Don't forget tricks like hanging a loose chain from the upper end. Mel Bartels Benoit, If you are past the limit of what the mount can handle, and this is a ...
I will try that too. right now, having a 2 pounds steel weight at the end of 1 foot of rubber tube, looks pretty promissing actually from what I can see. but...
Hi Mel! I hung a 15 pound weight from the head of a tripod made from wooden crutches. It is the mount for a home made pantograph and a pair of very heavy 20 x...
Hi Art, The weighted tripod works very well. It puts the tripod under pre-load, stiffening it. The hanging chain from the end of the OTA is a vibration...
lot of good info here but the worm gear system .... is it the best sytem fo very low periodic error maybe some other system are better whitch one OR what is...
I would suspect that the harmonic drive system like used in Chronos mount is much better than a worm system but harmonic drives are expensive. There is no...
Al wrote: " The hanging chain from the end of the OTA is a vibration absorber as opposed to a damper. The chain steals the motion from the OTA, swinging while...
Hello group, One question about harmonic drives. Why does a worm driven GEM need counter weights, but the Chronos GEM does not? Is it because there are many...
RE: Harmonic Drive. I've wondered about it in the past but the price made it a non-issue, so it's nice to have an excuse to look at it. Here is the Wikipedia...
Yes, I believe that is correct. Then design allows for many teeth to be in contact at one time, hence no backlash. Harmonic stages offer a typical 50:1 or ...
