peroni

I love it! Been thinking about a pier for a while now and this option has been on my list. Great write up that I will follow and copy without shame

This looks like a pretty neat idea. I'll be interested to monitor the progress you make Do you have any thoughts on how the two parts would be joined together after cutting? Hinges to flip the top over? Or a gutter/channel so top sits nicely on the bottom part. You'll want to keep the rain out.

I use a straight forward tube with my lens, scope, and finder guider. This will allow you to adjust the length of the dew shield by sliding up and down the scope/lens should you start to see vignetting. Obviously for a scope as it is fixed focal length it's easier to determine the length of dew shield. For the lens, a bit more trial and error. If you open the lens to a short focal length then a shorter dew shield is required. Not sure if the benefits of shield would be lost at say 18mm FL My vote says try the tube first. If it doesn't work. Go down the more complicated cone route.

I think the rule of thumb is to extend the dew shield by 2 x aperture, adding a bit to fix to the end of the scope / lens. I made mine to be 3 x aperture and all is ok

I have the camping mat as well but joined mine by taking some wool and a large needle to sew up the join. Works a treat and is nice and snug. For my finder guider I grabbed a neoprene beer mit and cut the bottom off.