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Practical Astronomy magazine cover image
EQ6 tripod top plate

EQ6 Tripod Top Plate (with stop post for fine adjustment in place)

Over the last week, I have made a telescope pier for well under £100, as I described in this article.

The next step was to fit my telescope mount to the pier.  The mount is an equatorial type, the Skywatcher EQ6.

The pier and mount together will be the basis of my home observatory.

Now, there are a number of commercially made pier adapters, designed specifically to join an EQ6 mount to the top of a telescope pier.  And I’m sure they are good items, but they typically cost around £75 each.

I have come up with a much less expensive option. It’s quite crafty, I think..  Here it is described below.

The main idea is to use the top plate from the tripod, which comes with the mount.

It is a sturdy steel item, that is obviously designed and shaped to fit the bottom of the EQ6 mount perfectly.

So all I had to do was fix the tripod top plate, securely to the pier.

Tripod top has a flat underside

Flat Underside Of The Tripod Top

Now rather helpfully, the tripod top has a nicely flat underneath side (see picture).

So it will easily sit flat on the top plate of the pier.  But how could I fix it in place?

Normally, the mount is fixed to the tripod by a central 12mm metric (M12) bolt.

This bolt passes through the tripod top and then screws into a threaded hole on the underside of the mount, thus holding the mount and tripod tightly together.

So I decided to make a modified bolt, which would pass through the pier top plate and the tripod top, then screw into the mount.  This bolt would hold all three items together.

A benefit of this arrangement is that the tripod top and therefore the mount too, can be easily rotated to achieve polar alignment.  Consequently, the positioning of the telescope pier itself, is not important.

And for fine rotational adjustment, the two screws built into the mount can still be used as normal, because the metal stop post remains in place, screwed into the tripod top.

The Modified Bolt

stud for central fixing bolt showing thread section filed smooth

Stud For The Central Fixing, Showing Thread Section Filed Smooth

The key feature of the central bolt is that it must rotate freely in the tripod top plate.  This allows the mount to be pulled tight against the tripod plate.

The original bolt supplied with the tripod, has a smaller diameter where it passes through the tripod top.  This allows free rotation.

So having cut a short length of M12 threaded stud to use for my central bolt, I smoothed-off the thread with a file, where it was to pass through the tripod top.  (see picture)

Conclusions So Far

ready for mount to be screwed onto the pier

Ready For Mount To Be Screwed Onto Pier

This arrangement seems to work well in practice.  It is easy to attach the mount to the pier and orientate it for polar alignment.

And everything seems secure, once the central fixing bolt is tightened with a pair of lock nuts.

So far, I don’t think any additional fixing will be needed to prevent any unwanted rotational movement of the mount. The single central bolt seems sufficient to hold everything tight.

However, should it prove necessary to secure the tripod top more, the pier top plate could be modified quite easily.

A further benefit of this approach is that the tripod top plate can easily be removed and the tripod reassembled, should you need to use it.  The tripod top has not been modified in any way. So only three nuts and bolts are needed to reattach the legs and assemble the tripod.