I'm trying to find information on building an outdoor observation area. I live on an acre and am planning on building my kids (5 & 8) an outdoor playground/playhouse...I would like to incorporate some kind of elevated observation platform that the whole family could use.

This could be anything from just a large platform on top of everything, all the way on up to something fully enclosed with retractable roof/walls.

The latter is probably something my wild imagination is getting carried away with and would likely be way out of my budget. As to what my budget is, I'm really not too sure, I guess that would depend on how cool the end result would be. Probably anywhere from a few hundred to a couple of thousand over and above the play area itself.

Does anyone have any suggestions as to where I might start?

Whatever you build will require a rock-steady base, either a pad or a pier depending upon what telescope you'll be using, to prevent vibrations from being transmitted to the telescope.

http://www.homedome.com/chpt6b.htm

http://www.ccastronomy.org/reference...0Observatories

Dave Mitsky

__________________
Chance favors the prepared mind.
De gustibus non est disputandum.
Never attribute to malice that which can be adequately explained by stupidity.

This sounds like a recipe to observe lots of vibrations. As Dave said, you'll need something extremely solid and vibration proof to be an effective observing platform. I've had my scope on my deck (yes, a poor observing location) to show guests the moon, and I can see vibrations in the scope when there's any movement inside my house, even just the dog walking around.

I recommend a giant cube of concrete, because anything else will probably shake like crazy with walking or wind. I set mine up on a porch once. Kinda sucked.

But seriously, if I were to make a platform, I would dig down to bedrock or below the frost line (so it doesn't break or list later), pack in a layer sand or crushed rock or something (ask a professional) and then make a pad. I'd make it perfectly level and have some sort of indication for true north AND for where exactly to put the feet of my current tripod. Like dots, or maybe draw three lines from the center of the pad: one true north and the other two exactly 120 degrees off. That would save like 15 minutes every time I set up the telescope.

I should mention the porch I used was about 4-6 inches off the ground, sitting on concrete pilings, and still shook.

I should also mention that sand and crushed stone have the exact opposite drainage properties and using the wrong one may lead to disaster, and I don't remember which to use in what situation.

Thank you everyone for the advice. I really hadn't given a lot of thought to vibrations (obviously)...I think I'll have to alter my plan significantly.

Crazy idea, probably - If I were to have a platform about 10 feet up, for example, would it be feasible to build a concrete pier up through the middle? I'm thinking that would have to be at least 15 feet, so that may be a crazy idea as well. I didn't see anything like that in those links (great links, BTW, thanks); I'm not sure how realistic such a thing might be.

It will be tough to do. Maybe a cinder block column filled with small gravel to absorb vibration might work as a central support?

__________________
"I'm as accurate as any psychic. And I'm a cartoon!" -- Squidward

"Arrrgh, the laws of physics be a harsh mistress!" -- Bender

A friend of mine has a Home Dome that houses a 20" f/10 classical Cassegrain. The building is two stories high and has a tall central pier. Needless to say it wasn't very cheap to build.

I've attached a shot of C/1995 O1 (Hale-Bopp) and my friend's dome that I took in the spring of 1997. I met Dr. Hale later that year and he was gracious enough to autograph the photo for me.

Dave Mitsky

Attached Images

Comet Hale-Bopp over Bob's Dome.jpg (110.4 KB, 12 views)

__________________
Chance favors the prepared mind.
De gustibus non est disputandum.
Never attribute to malice that which can be adequately explained by stupidity.