May 18, 2022: Replacing the battery in the Astro-physics keypad

Michael Richmond
May 18, 2022

During our Open House on Sunday, May 15, I attempted to use the 14-inch Celestron to show our visitors some globular clusters. I was able to point to a star, sync the telescope, and then move to another star simply by choosing that new target from its menus. No problem. However, if I attempted to move to a Messier object, or an NGC object (instead of a star), the system would complain that the object wasn't up in the sky (even though it clearly was).

It turns out that this is a symptom of a dead battery: specifically, the battery which maintains the "object database." This does NOT include bright stars, but just about everything else. The solution, as described in the Astro-physics keypad manual, is to replace the battery and then download a new copy of the database.

Today, I carried out the first half of the job. I purchased a new CR 1632 battery. I then followed the instructions at

After opening the keypad, we can see the old battery, partially covered by a ribbon cable, and very close to white cables on the left.

First, I remove the ribbon cable, and the white cable set. That made removing the battery much easier -- but it was a slow and gradual process. Below is a picture showing the new battery in place.

I then replaced the ribbon cable and the white cable set.

After that, I replaced the back cover, and put the keybad back into its rubber sleeve. Taking things slowly and gradually is a good idea.

Finally, I took the keypad out into the rolloff structure and connected it to the mount. I turned on the power, and the keypad booted up as usual.

It turns out that we are currently running keypad software version 3.09. The most recent version is 4.19, so we might want to update it at some point.

My next step will be to download a fresh copy of the object database.


Last modified 5/18/2022 by MWR.