Backyard Astronomy

Astro-Physics 1200 Telescope Mount

In October 2008 we bought an Astro-Physics 1200 mount to replace a Losmandy G-11. This page shows how we installed the AP1200 on the concrete pier in our observatory.

Installing the Pier Adapter

The Astro-Physics 10" standard pier adapter (SPA) is large enough to span the four ½" bolts protruding from the top of the concrete pier. I drilled and tapped a ¼"-20 hole in the end of each bolt, then drilled and counterbored four holes in the SPA for ¼" cap screws. The cap screws fasten the SPA securely to the top the four bolts, and the nuts serve as a leveling adjustment for the SPA. I used a machinist's bubble level to adjust the SPA to within 8.6 arcsec of level (1 division on this level equals 1.4 arcmin, and I got the bubble to within 1/10 division).

The AP1200 attached to the pier adapter installed on the concrete pier.

Cable Management

Because no one is present in the observatory while the telescope is acquiring images, it is vital that the telescope be able to perform the meridian flip without snagging any camera cables. These photos show the additions I made to my equipment to prevent cable snags.

I added a ¼" steel rod to one of the aluminum blocks that support the telescope, and attached a mini bungee cord to it. This holds the camera cables away from the AP1200 control box.

I also added two 1/8"-diameter brass loops over the connectors that plug into the control box. These ensure that any dangling cables will not snag the connectors.

The ends of each loop are tapered to resemble a flat-blade screwdriver so they fit into the crevice between the AP1200 RA axis housing and the polar fork base assembly. The loops are held in place with Goop viscous adhesive. The Goop holds the loops securely, but it can easily be broken free and peeled off in the event the loops ever need to be removed.

Update. A couple of flip movements revealed that, due to its orientation and length, one particular cable was falling between the loops and snagging the AP1200 motor cable connector. I glued this shield made from aluminum flashing to the brass loops to prevent this.

Updated September 7, 2016