Basic Assembly of an Equatorial Mount

Let’s set up the EQ mount from the basic parts. This is probably how it arrived when you purchased it. You won’t always be setting up “from scratch” like this because, depending on your situation, you will probably leave the mount partially or completely assembled between observing sessions.

First we extend the tripod legs and spread them to approximately the right final position. Unless you are on level ground, don’t extend the legs all the way – leave a little bit of adjustment on each leg for doing coarse levelling later.

Next, install the centre tray if there is one. Most tripods have a centre tray. This is not only to provide a convenient place to put small parts, but it serves as a spacer and brace to hold the tripod legs at their correct positions. So the tray, if there is one, is not optional – you must install it.

On some mounts the tray is actually a stretcher – i.e., it is forced upward between the legs under pressure, holding them outward and adding to the rigidity of the tripod. The M4 mount in most of these photos does not do this, but this Celestron CG-5 does – the tray is pressed upward by a screw, holding the legs stiffly apart. (This CG-5’s tray has lengths of heavy automotive radiator hose slipped over the ends, to cushion vibration.)

Now we’ll put the EQ head on the tripod. Looking under the head, note there is a central hole drilled and tapped for a mounting screw and, on one side, a chamber containing a gap between two adjustment screws. The top of the tripod has a hole for the central protrusion, and a protruding shoulder that must go into the gap between those adjustment screws. (Click the photo at right to enlarge it for a clearer view.)

Place the mount head on the tripod so the shoulder is in place between the adjusting screws, and tighten the mounting screw from underneath so the head is secure.

Now we thread the counterweight shaft into the threaded hole in the underside of the mount and tighten it.

At the end of the shaft will be some kind of screw or nut that thickens the end of the shaft. This is to prevent the counterweight from accidentally sliding off, and is therefore called a safety screw.

We must remove the safety screw to get the counterweight on the shaft.

Slide the counterweight on the shaft.You may have more than one weight, possibly of different sizes. You will learn which weights you need when you balance the mount.

Tighten the clamping screw on the weight so it stays on the shaft, near the top for now.

And immediately replace the safety screw so the weight cannot fall off.

There are a few other suggestions that will make setting up your mount easier, and these are good habits to form.

• The first time you set up should be in daylight. It’s complex enough without being unable to see what you are doing.
• In fact, in general it’s better to set up in daylight or twilight while you can still see, then relax while darkness falls. That way you won’t be wasting your observing time fumbling with equipment in the dark, and you will be giving your optics time to cool to the falling outside temperature.
• If possible, set up in a location where you have a clear view to the North. You’ll want to be able to see Polaris (the North Star) to complete the alignment process.
• When setting up on grass, dirt, or gravel, lay out a light-coloured tarp and set up on that. This will make it much easier to find and retrieve small dropped parts, especially in the dark.
• The first few times you use your telescope, set up on grass or firm dirt, not concrete. You’re likely to drop things until you become accustomed to handling them, and parts dropped on concrete will break. (Parts dropped in the grass will be lost, but at least they won’t be broken.)

The next step is to attach the telescope to the mount.