On Aug 22, 12:20 pm, HK wrote:
wrote:
On Aug 22, 1:15 am, "Calif Bill" wrote:
"hk" wrote in message

m...

wrote:
On Aug 21, 5:39 pm, (Richard Casady)
wrote:
On Thu, 21 Aug 2008 10:49:35 -0700 (PDT),
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.
Put it under a bell jar and pull a vacuum on it.
Casady
I was only 17 when I did that so had no bell jar.
Do I understand this? Someone is going to mount a telescope on a small
boat?
Hehehehehehe.
Fascinating place, rec.boats is.
Ought to be useful when the boat is on a trailer in the driveway.
I take my telescope with me at times boating. As well as the spotting
scope. Lots of times we are beached and can use the good optics.

The idea here is very low f# and very low magnification. In general,
the motion of a boat at anchor is not as much a problem for such
casual viewing as is the shakes of a person holding a scope. This
scope is intended to be held in ones lap while sitting down. Foam
around the scope base will be used to dampen shakes from the person
holding it. This is not for serious astronomy but only for very
casual looking at stuff. I have an 8' scope on a mount for serious
stuff. So Harry, do the math before you criticize.

I didn't figure you were using it for astronomy. I have a decent little
spotting scope I use for target practice. Even though it is mounted on a
low tripod, I haven't found it useful on either of my Parkers because of
boat movement. Must be a lot calmer where you boat.

You have a telescope with an 8' glass? Holy schitt. Great for bikini
watching, hey?

I admit, 8' is a little big. 8" is more like it.