Under 100? Nah. The cheapest 'telescope' would be about 150, and it'll show everything upside down and backwards. Spotting scopes go for 500+.
20 x 100 binocs can see almost as well, and they are tripod mountable (or other fixture), and easier to move around. You may not need that much magnification, but that's the max for 'nocs, and you can use them on a swaying deck
. You can clean them easy, store them easy, and they'll have a long life if cared for.
Caveat: If you actually want to look at stars (and see your scope
decay within a year), I'd recommend a Dobsonian scope
without guides or motors... although now that I think about it, a lot of the bases are made of particle board, but they can be replaced with metal or hardwood easily. If the dock
isn't moving too much, you can still see good stuff once you get the hang of manually moving it. I can follow satellites easily. I dream of being in the middle of the ocean on a calm sea with my scope.
For an example, go to telescope.com and find the Orion XT6 Dobsonian beginner kit. 300 bucks, which is cheap
. The metal will eventually rust away (especially because it's sooo cheap), but the mirror and focusing mechanism is what's important. More or less, a telescope is a bad idea on a boat
just because it'll fall apart in months.
Astronomy folk... aw hell, every sailor is an amateur astronomer... download Stellarium (stellarium.org), for the best night sky program. It's free and invaluable for any astronomer.