Mach one Clutch release knobs

I am very much enjoying my Mach 1, it is the perfect mount for a 5 to 6 inch refractor or Mak-Newt. I have two issues, though. One is the loud noise it makes when slewing--I presume this is because the motors are more exposed than they were on my AP600. The other is the difficulty I have loosening and tightening the clutch release knobs on the DEC and RA axes. Does any after-market manufacturer make a larger, easier to grab knob, like the heavily studded knobs that Losmandy sells?

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Robert Howe said:

I am very much enjoying my Mach 1, it is the perfect mount for a 5 to 6 inch refractor or Mak-Newt. I have two issues, though. One is the loud noise it makes when slewing--I presume this is because the motors are more exposed than they were on my AP600. The other is the difficulty I have loosening and tightening the clutch release knobs on the DEC and RA axes. Does any after-market manufacturer make a larger, easier to grab knob, like the heavily studded knobs that Losmandy sells?

I haven't seen any mention of after market knobs. They would get too large and start to interfere with the mounting plate. I find that I can adjust the knobs somewhat tighter with a hex key after hand tightening if there is not enough friction.

Agreed, she be a noisy one slewing, especially at 1200! Even at the 600 speed it seems very noisy, but I wouldn't trade mine in on anything. It is super accurate, has excellent capacity, is relatively lightweight and appears to be bulletproof, by far my favourite mount for a 4 to 6 inch instrument.

>>One is the loud noise it makes when slewing--I presume this is because the motors are more exposed than they were on my AP600.>>

The reason for the louder noise on the Mach1 is twofold. First, the servomotors are 3 times as powerful as on the older 600 mount. Secondly, the 600 was geared using a commercial gearbox mated directly to the motor. The reason we chose not to do that is due to the nature of all commercial gearboxes - basically the tiny spur gears on all gearboxes are very small and have only a few teeth. This makes them very quiet even at full slew speed which is close to 10,000 rpm for the servo motor itself. The downside to these small spur gears is that they impart a cyclical oscillation to the output speed when tracking. This means there is a short period variation superimposed on top of the longer period PE. These short period speed variations, even if they are only 2 - 5 arc sec in height, means that the guider must work much harder during guiding, plus you cannot get good long period unguided tracking, even with periodic error correction implemented. In order to eliminate these short term variations we decided to make our own gearbox (same as with the 900/1200 mounts) and use high quality, large size, precision spur reduction gears with lots of teeth. This results in ultra-smooth tracking, which is the name of the game for getting high quality images.

Of course, running a servo motor at 10,000 rpm into a set of gears with 75 and 100 teeth on the high speed gears results in a number of audible whining noises that resembles a miniature jet turbine. We didn't have a heck of a lot of room left for sound deadening material inside the gearbox (it is already crammed with gears and motor) so it was not possible to do much about the sound. You can reduce the noise level substantially by running the GoTo at 900 or 600x, if noise is a major concern. You will get there pretty quickly either way.

Rolando