My previous observatory in Sheffield was a steel frame and canvas
affair sold as a large motorbike cover. While it worked quite well,
the canvas would eventually grow thin and tear and need replacing
every year. Somewhat annoying but I lived with it... However, last
year a heavy snowfall caused the whole thing to collapse - a major
rethink was needed. I finally decided to design and build something
from scratch as I had fairly tight constraints on weight and footprint
etc., so a bespoke solution appeared the only way forward. I finally
settled on a roll-off shed, with just enough space to cover the rig. A
roll-off roof would require too much space with the extra
supports. The whole thing is on a 'tripod' of three wheels to prevent
wobbling on my uneven drive (no new and level foundations were
possible). The wheels are on a heavy timber frame which also supports
the shed itself. The front side is removable in two pieces (I couldn't
lift one alone). The wood is treated and varnished to within an inch
of its life, and the roof is three layers with rubber on the
outside. It has seen one round of the seasons so far, so I am hopeful
that it will last longer than the bike cover!