I’m pretty sure this is how E.T. got called to earth in the first place.


A new invention for amateur astronomers is said to make self-instruction in the secrets of the skies easy and absorbing. It is a homemade planetarium, which reproduces in miniature the dome of the heavens, showing the planets and constellations mapped out in their proper positions.

The unique contrivance was constructed by a New York City inventor from simple frame parts of metal and wood, while an old umbrella hood served for a dome. It rests on wheels so that it can be moved about without difficulty.

Attached to the frame is a series of bar magnets placed in line with the wooden strut which supports the umbrella dome. If the device is held off the ground by a string, these magnets swing the frame so that the center point of the dome points directly at the North Star. The astronomer in this way obtains his bearings, and is ready to study the stars by verifying their positions according to the carefully labeled map on the inner surface of the umbrella dome.

  1. Richard says: July 13, 20113:18 pm

    In his book “The Stars”, H.A. Rey has an illustration of an “umbrella planetarium” to demonstrate how the stars appear to rotate around the North Star (of course, Earth is what’s rotating, but the appearance is the same as if the sky were spinning). I wonder if one got the idea from the other. I suspect it’s more likely that this concept was invented independently by both.

    I’m not sure the whole magnet thing to line up with Polaris is worth the trouble. I’ve taught my five year old daughter how to find Polaris, and it’s one of the first things a star gazer in the northern hemisphere learns. Anyway, if an aid is needed, manually using a hand held compass to find north is cheaper, simpler, and lighter weight than the contraption shown.

  2. mikeburdoo says: July 13, 20117:06 pm

    Right on: the magnets are useless. If you can’t identify Polaris (which for the naked eye anyway, is always in the same place regardless of time of day or night or the date), you’re not likely to identify anything else. All you need is a compass and your latitude to find it. Of course it helps if you’re not in New York City.

  3. Stephen says: July 14, 20115:38 am

    I remember an invention of this kind in the 70s; it worked a lot better made out of transparent plastic. Of course, there is the problem of finding conditions bright enough to read the marks on the umbrella but dark enough to see the stars.

  4. Toronto says: July 14, 201111:25 am

    And don’t forget that nowadays, “there’s an app for that.” You can sync your Ipad/phone/whatever’s GPS location and exact time to a star map and show what’s in the sky. It’s kinda neat, though so far I’ve only played with a copy inside and during the day.

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