Saturday, December 2, 2017

New Mount: 10Micron GM1000 - First time out

With everything in place, I could finally take the mount out for the first time!!!

First, I wanted to try out the rough polar alignment with the green laser pointer on the scope. But either the laser is broken or WAY too weak, but I could not see a beam at all :-( So, scrap that idea.

Now, rough polar alignment turned out to be tricky. The 10Micron mount uses simple star alignments for polar alignment (3 stars for a rough alignment, a full model for exact polar alignment). But when the mount is not even nearly polar aligned these are difficult through a camera as the I can't use "Closed Loop Slew" in TSX or plate solving as the it is WAY too far off.

So, as I want to use the mount unguided anyway, I decided to remove my good, old Borg scope + Lodestar guider and replace it with a simple red dot finder:

Another nice side-effect of this is that there WAY less weight on the scope now. I could move my counterweights significantly up - maybe I can even get rid of the smaller one completely!!!

With a rough polar alignment, I tried various of the 10Micron functions:

1. Balance check
I really like that they put this into the functionality of the keypad. The mount moves the scope into specific positions and measures on both sides if any creates more or less friction. Measuring in RA was quick and showed that I was only 0.01% off (everything below 0.04% is considered enough for good, stable imaging).
For the DEC measurement, the tripod became an issue. As the mount is pointed almost straight to the side and moves the scope all the way from one side to the other, my filter wheel collided with the tripod and stopped the whole procedure:

This is another reason why I like the AP Eagle pier (the other one being that it has better possibilities to fix all the boxes).

The good news is that there is a dialog box asking for confirmation before slewing to the other point. At that moment, I can slew the scope further upwards and then it passes. But I should really try to get an adapter from the Eagle pier to the 10Micron mount. For now, I'll probably move the filter wheel around and point it upwards.

2. Orthogonality (cone error)
From the various alignment points, the mount calculates the orthoganility error. In my case it was 0!!!

3. Polar alignment
Now, the polar alignment was fairly easy. Select it in the keypad and do the usual azimuth/altitude adjustment to center the star.
While doing the alignment, I noticed two things:
  • to adjust the mount in Azimuth, the four screws that fix the mount to the tripod have to be loosened. And of course, I have to remember to fix them again afterwards.
  • the Altitude know has a significant amount of backlash (see above). It's not getting too much in the way of adjusting the mount, but it is weird that it is SOOOO much. Asked in the 10Micron forum about this.
But now, my mount is polar aligned.

4. Tracking precision
Without guiding, I measured the precision of the mount as-is (i.e. no model or such): << 1" !!! That's a pretty awesome precision!!!

5. Configuring in SGPro
The main difference in SGPro configuration was to switch from PHD2 guiding to "Direct Mount Guider". This basically doesn't do any guiding, but still does Meridian Flips and Dithering.
The other thing I wanted to configure is to not track too close to the Meridian to avoid that the filter wheel collides with the tripod. I measured that filter wheel collides roughly, when the scope is 5' away from the zenith. In SGPro, I can use negative values in the Meridian Flip settings dialog to indicate this:

... and then it got too late to really try it out ...