Re: AP600 vs Mach 1


Jeff B
 

Which is where most vibration comes from with portable instruments in my experience.  Now I believe that a robust rap test (or as in my job the "ping test") is a very severe test.  I've found I can get just about any scope/mount combination to ring if I hit it hard enough.  For example, if I gave the diagonal of my TEC200ED/AP1200 system a good thump with my index finger, while watching the image at high power, the image would indeed  go through about a half second of a well damped vibration.  However, a lower level touch or mpulse would result in no movement of the image.   The system had a high quality "Q", meaning it takes a certain amount of input to get its attention.  So from a practical point of view, for me, the better test is the ease of manual focusing at high power.  That involves me actually touching the focuser, providing a relatively continuous low level series of inputs or impulses to the system.  I've found if a system is easy to focus at high power, it also has rather decent wind tolerance.  I've also found that in general, spring loaded worms can display a bit more of a tendency for vibration when focusing compared with some drives that are not spring loaded (however, those can vibrate as well from a bit too much backlash).  

Jeff


On Thu, Mar 31, 2022 at 12:56 AM <weems@...> wrote:

I ran some tests on terrestrial objects today. With the tripod feet firmly in the ground, and everything tight, the 35lb 6”f9 OTA, when rapped firmly on the focuser, showed about a 0.8 arcminute vibration that dampened in 3.5 seconds. The flexure seems to mostly be in the hardwood tripod. 


Chip

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