Astro-Physics 1600GTO German Equatorial Mount

When I traveled to NEAF (Northeast Astronomy Forum & Telescope Show) in April of 2012, I had no idea I was about to make a major upgrade to Bifrost Astronomical Observatory. My very first stop at the show as a visit to the Astro-Physics booth so see what was new. My eyes quickly focused on the new equatorial mount just unveiled that morning: the AP 1600GTO. As I scanned the list of specifications for the 1600, one feature jumped out at me: Weight Capacity: Approximately 220 lb. (100 kg). This was nearly 60% more than my AP 1200GTO.

I'd only been using the AP 1200GTO for a little over two years and I was very happy with it. It performed excellently and I had no complaints considering that I already had it maxed out with nearly 140 pounds of telescope gear (AP 130mm EDF Refractor, Takahashi Epsilon 180 ED Astrograph, and an ASA N12 Astrograph).

But that was the whole point. I was already near the maximum weight capacity of the 1200 with no room for future expansion. And the 1600 was attractively priced, offering a lot of mount for the money.

I mulled it over for all of 10 minutes before signing up on the notification list. That is, the list to give you the first opportunity to actually place an order once the 1600 was in production. I was notified in mid-August and placed my order with an anticipated delivery date in February 2013. Astro-Physics contacted me again in late January 2013 for final payment and the 1600 arrived several weeks later.

By the end of February, I was ready to instal the new mount. This was a major task because it meant carefully removing all the telescopes from the 1200 mount first. The 1600 also has a clever cable management solution by passing cables up through the mount instead of leaving them hanging off the telscopes and inviting potentially damaging snags. I gave some serious thought to the types and number of cables to snake though the mount with an eye towards future equipment needs. By early March, the new mount was in place and the telescopes were all restored to their former positions on the Robin Casady MultiScope32 Tandem Bar.

After some driver updates and a few system configuration changes, I was ready to test the mount. Two nights were used to refine the polar alignment via PemPRO.

I have now been using the AP 1600GTO mount for three months and it operates flawlessly. Although it carries the same load as the 1200, the 1600 to seems to handle the weight more smoothly and it slews with less effort.

Below is a table of the techical specifications on the AP 1600GTO. For more information, see Astro-Physics web site.

Astro-Physics 1600GTO Equatorial Head Specifications (2013)
Worm wheel - RA & Dec 10.3" (26.2cm), 225 tooth aluminum
Worm Gear - RA & Dec 1.22" (31 mm) diameter brass
Axis Shaft - RA & Dec 3.74" (95 mm) diameter
Shaft Axis Bearings - RA & Dec 5.71" (145 mm) diameter
Latitude range 0 to 78 degrees and 90 degrees for Alt-Az
Azimuth Adjustment ~13 degrees (+/- 6.5 degrees from center)
Counterweight Shaft 1.875" (47.6 mm) diameter x 19.5" (495 mm) long [18.5" (470 mm) useable length].
Weight of Mount Total: 114.0 lb. (51.8 kg)
RA axis/polar fork: 58.5 lb. (26.6 kg)
Dec axis: 38.5 lb. (17.5 kg)
Dec top plate 3.0 lb. (1.4 kg)
Counterweight shaft: 14 lb. (6.4 kg)
Capacity Approximately 220 lb. (100 kg) scope and accessories (not including counterweights), depending on length.
Pier Adapter Base Diameter 9.775" (248.3 mm) Base. The base is an integral part of the mount and azimuth adjuster.

Bifrost Observatory Index

Bifrost Astronomical Observatory