Davoud wrote:
The expert said that it is unnecessary to mount the pier in this
manner;

The expert is correct.

He said that it does not matter whether the pier is exactly
perpendicular to the base; a couple of degrees in any direction will
not affect telescope tracking.

That is entirely correct. As Chris has stated, there is exactly one
condition that needs to be met, i.e. that your polar axis is parallel to
Earth's spin axis. Obviously, from a mechanical point of view you don't
want the pier cantilevered at some crazy angle, but even if that was the
case, the base would still be parallel to a perfectly horizontal base
*somewhere* in the world. Or, put another way, those who insist that a
base needs to be perfectly horizontal are also insisting (by
implication) that their location is the only one on the planet from
which polar alignment is possible. This is clearly ridiculous!

I've always assumed that that is why they put bubble levels on wedges.

They help if you are setting the wedge purely according to its altitude
scale, as opposed to by some optical method of polar alignment. They
also help to ensure that your tripod is not so canted that it might fall
over or be otherwise unstable in some orientations of its load.


Best,
Stephen

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