Giant educational Celestial Sphere

[Peter Butchko]

About 20 years ago, I came across an astronomy company who made a giant celestial sphere (6-10 foot diameter?)... made of either aluminum tubing or PVC...that you could sit within. I think it had the Celestial Equator and Ecliptic, and could be made to rotate around you to help explain how the sky moved. Or perhaps you could rotate it until it matched the sky above you....don't quite remember. Recently I have tried to locate plans or at least a photo to build one myself (I teach HS astronomy), but have been unable. I was hoping someone else might know anything about it...

[Ron Schmit]

The Adler down in Chicago has something similar to what you describe. It's called the Atwood Sphere. Maybe they could help.

[Dale Smith]

I went to Amazon.com and typed in Planetarium. There were many desktop projectors. About 5 screens in there was one called
Sayok Portable Inflatable Planetarium Projection Dome Tent for School with Air Blower and PVC Floor Mat
It was about the size of a 2 person dome tent, but at $1400 is probably too expensive.

I also searched on Celestial Sphere and came across
17.5" Tall Eisco Labs Celestial Star Globe - 12" Globe Diameter
This is a clear plastic globe sortof like a world globe, only with stars. Suspended inside is a little globe of the earth. This may be a more easily stored alternative to something you climb into.

[Peter Butchko]

Thanks.

Yes that inflatable dome is like the one the Bell Museum offers... they came to our school last year and did some shows. Pretty cool.
And I just checked out the Atwood Sphere at the Adler. That is very interesting, but not quite what I remember. That looks more like a solid sphere with holes poked in it...like a primitive planetarium...would love to see it!

In this contraption that I seek, I imagine sitting in a seat outside with this large tubular framework celestial sphere around me....mostly open to the environment....and you could look up during the night (or day for that matter) and see the sky through the frame, and see how the CE and Ecliptic rotate around you....

I also contacted the Astronomical Society of the Pacific...because they do stuff like this...and I thought maybe this thing was offered through their Project Star.... well, in the meantime, I will keep looking.

[Deane Clark]

What you describe sounds like it would be fun, but with the current availability of smartphone apps that basically do what you're describing, I can see where a physical one might be a hard sell.

[Dale Smith]

If I am envisioning your request correctly I think what you want is basically an armillary sphere or rather an armillary hemisphere.

Check out the Wikipedia article on Armillary Sphere and then go over the Wikimedia Commons and check out pictures of armillary spheres and let me know if that gives you any ideas.

[Peter Butchko]

Yes, I agree...it is a human sized armillary sphere that you sit within. No luck yet. Maybe it was not successful and not used afterall. Maybe I am only imagining it....sure I saw it somewhere...

Anyway, as you suggested, I went to Wikipedia and checked out the pictures....lots of beautiful ones. My favorite is in ibirapuera park brazil:
https://commons.wikimedia.org/wiki/File ... ini_08.jpg
Looking at this, if you got rid of the circles for the Tropics and put a chair in the center....then place a sun on the ecliptic and rotate the whole thing around you, you could get a visceral feel for the heavens different from just sitting at a computer screen in 2-d....

I also found s a radioastronomer who built a celestial sphere of PVC to help visualize radio sources:
https://users.physics.unc.edu/~reichart/sphere.html

Thanks for your suggestions, everyone. I will let you know if I find it....