Counterweight Balance Tutorial

Whenever you attach a telephoto lens to your star tracker, it needs to be balanced.  If the gear is not balanced properly, it will put a lot of stress on the tracker's motor.

Think of it like this:

The motor inside the star tracker is like a scrawny guy at the gym. The motor needs to very smoothly and precisely lift your camera gear all night long. This is what gives you sharp stars. Our guy at the gym needs to have good form when he's lifting weights, with smooth, controlled reps. If you give him too much weight, he will not be able to maintain his good form and he may start jerking the weights around. If the weight is way too much for him, he may get injured. Or, if you put 45lbs on one side of his barbell, and 10 pounds on the other side, he's going to struggle to do his chest press exercises. He needs the weights to be properly balanced on each side.

Therefore, we need to make it as easy as possible for the star tracker. We can't go over the weight limit, without incurring tracking errors. For most star trackers, the weight limit is between 5 - 8lbs. This includes all of your gear - camera body, lens, L-Bracket, lens hood, auto-guider, etc... (Don't factor in the counterweights)

We also need to make sure both the Right Ascension and Declination axis are balanced. If either one of these axes is not balanced, the tracker will be struggling all night long.

A balanced setup will not only increase your tracking accuracy, it will increase the lifespan of your tracker.

I highly recommend practicing your balancing workflow in your house, on a carpeted floor. It is very easy to accidently unscrew the wrong thing, and have your gear crash to the ground. (Especially on a cold, dark night).  After you've practiced a few times, you're ready to take the gear outside!