GM2000
My new mount 10Microm GM2000 replaces my old AP 1100, my motivation for the upgrade grew
out of the realization that my astrophotography
quality needed a with dual decodes which lack the replaced mount. Two
things matter to me: avoiding wasted time during an overnight session (caused
either by images thrown away due to tracking errors or by time spent repeatedly
trying to properly frame the desired variable star), and image quality (which
affects photometric – brightness measurement –
accuracy). This is a personal expression, but never got the reliability
to the point where I could trust it to work during unattended overnight
sessions.
What made the GM2000 so
attractive is that it uses absolute encoders on both the declination and RA
axes, which virtually eliminates periodic error. The company claims that
tracking error is routinely less than 1
arcsecond, What appealed to me is that
10Micron doesn't sell any version of the GM2000 without absolute encoders,
which has permitted them to optimize the entire control system around the use
of the encoders.
Installing the GM2000 onto my
pier was straightforward, just requiring a few holes and bolts. The most
difficult part of the installation was wrestling the
30 KM of mount up onto the pier. The image below is a picture
showing the new mount, telescope, and camera.
It then took a couple of weeks to finish upgrading my software to
handle the computer interface to the GM2000 and
to build a "mount model" in the GM2000 firmware.
To build a mapping
points model there are third parties software , this are ModelCreator or Mount
Wizzard. It a be tricky to setup the communication channel , but once you
connect it a great program.
The firmware has a very nice
polar alignment tool, eventually 5 arcseconds
away from perfect.
This time I used
Polemaster to assist me , thou you need first to do a three stars alignment
followed by the polar alignment and if you use the mount PL you would need
again to do the three stars alignment.
The general "feel" of the mount is wonderful. The GM2000's
firmware seems solid. When you execute a goto, the mount does it quickly and
accurately, the same every time. When things go wrong, you don't need to cycle
power to get the mount working normally again; instead, just fixing the problem
makes the mount happy again.
The mount performs "two-axis tracking," with both the declination and RA motors involved in the tracking process. The mount's pointing model is translated by the firmware into both a declination tracking rate and a RA tracking rate. Thus, the two-axis tracking is able to compensate for all of the known elements of small misalignment. I've run the mount last week for the first time given that when setting up the connection to SGP it platesolving was not aligned with the mount RA/DEC coordination. The issue was the mount software memory stick firmware version, thinking that it was latest in reality its was old, quite old (1.22) when the current update with 1.5. After realizing this and quite annoyed that they sold me a nearly two year old mount (new , but old if you know what i mean) I did a fully automates of five hours overnight sessions, connected and sync to the dome.
For my exposures (up to about 6 minutes), there is no visible tracking error.
Typical star images have FWHM widths of about 1.9
pixels.
Mount in action
