Calculating the volume that contains a telescope on its mount
The proper way to do it is to make a 3D model of the telescope on its mount, animate the two axes and look for collisions with a box or a sphere that grows as it collides. I'll try that with FreeCAD and a python module someday.
In the meantime, I've written a simple console program that takes measurements of the hardware as inputs, creates a 3D scene graph, animates the axes and checks for longest distance for all points in all positions. It has not been much checked for the exactitude of its results, it gives me a sphere of 62cm radius for an NEQ5 with a Mak152.
It only works with a bounding sphere, a german equatorial mount and a telescope with instruments at the back, like refractors or catadioptrics, but could be adapted to work with a bounding box and other kinds of mounts and tubes. It is written in scheme, be prepared to cry if you want to modify it, but it's my favourite language.
Building a cupola
There are many designs of spherical cupolas for observatories. Those found on the market are good quality but very expensive. Here we'll explore how to build one that is weather-proof, motorized and not as expensive.