On Aug 21, 1:49 pm, wrote:
On Aug 21, 1:46 pm, wrote:

My daughter is sick so I have to stay home if she needs me. There is
light rain from Fay so no working on the boat.

So..........start a project I have been planning, a boat telescope.

I like casual astronomy just a little better than 7X50 binocs and I
know about optics and ground a telescope mirror when I was a kid. So,
this project is a 4" diameter mirror of only 20" focal length and low
magnification for very wide field of view.
After 1st half hour of rough grinding, I have a definite bowl in the
mirror.

I tried that liquid mirror thing once, or at least an infra-red
variation. I put a bowl of epoxy on my old turntable and spun it for
several hours till it hardened. It sorta worked but I did not manage
to get the bubbles out so he surface was covered with tiny pockmarks.

Unfortunately, it is seriously hot in that utility room. After an
hour of grinding, the bowl shape can be seen with naked eye instead of
sighting under a straightedge