Make a demo one out of cardboard to get the sizing right, then cut one out of thin black foam (Clark rubber) and put a 6 inch wide over lapping piece at the join to give it strength. Join it together with a hot glue gun and use a scapel to trim the dew shield so it fits past the dove tail bar.
If you have the glue gun and scapel - you're up for around $20 in materials make a custom or over sized dew shield.
I'd highly recommend one of the rollable solid foam camping mats. the ones that are about 1cm thick. Mine is blue but you can get gray ones. Cut to length such that it does just over one lap around the OTA then attach with one of those pull-through straps also cut to length.
- easy to take on/off
- extremely light weight (is there anything lighter??)
- insulates hence improving efficiency of any dew heaters you have
- indistructable, easy for transport
- cheap
Roger.
[edit] matt beat met to it.. same principal I think.
