Dirt Cheap Telescopes With Liquid Mercury

Decibel writes "Scientists at the University of British Columbia have built a 6 meter telescope that uses a plate filled with mercury for its primary mirror. At a cost of $1 million, this technology makes it possible for many research teams to have continuous access to a telescope, rather than sharing with many other researchers. On a somewhat related note, the top 10 images taken by the only company that provides commercial satellite images at 1 meter resolution have been released to the public. Included are pics of the Olympic Park in Sydney, the Hollywood sign, Hoover Dam, and the Great Pyramids of Egypt. I don't know how they determined that these were the top 10, but they're certainly worth a look."

Personal addendum by jamie .

Summer 1983: I was at a cool kids' summer camp learning about astronomy. I was 12. A friend and I came up with the idea of spinning mercury into mirrors. We didn't know much about optics or physics and had no idea if it would work, but we presented the idea to the Very Smart guest speaker the next day.

He thought about it for a second, and shot us down: he didn't think it would focus properly because the surface would be a catenary, not parabolic.

I would just like to take this opportunity to say: in your face, dude.

Mercury mirrors do not, however, make good replacements for general-purpose telescopes. They only point straight up; they'll never do long exposures or see anything outside their latitude. I'm a little surprised the article doesn't emphasize this.

(On the off-chance my "co-inventor" Bill Hall, from Kalamazoo, Michigan is reading this: drop me a line, Bill.)

Comments

The "pointing straight up" part...

[No Such Agency]

Caveat: IANAA(stronomer)

If the main telescope mirror has to be flat, why can't light be "piped" onto it by targetable accessory mirrors? Is there some reason that an apparatus of optically flat mirrors couldn't be used, in place of conventional telescopes where the whole thing moves? My only thought is that maybe the light would be diminished by being bounced around, and so maybe very dim objects couldn't be seen as well. And the accessory mirrors wouldn't require as massive a mount to hold them in place, would they?

Re:The "pointing straight up" part...

[Signal 11]

Any impurities in the refocusing mirrors would be duplicated in the result. The whole point of a liquid mirror is to kill the impurities.

--

The problems with the mercury telescope

[ErfC]

As one of my profs once said, "There are two problems with the mercury telescope. It can only point straight up. And the fumes make you go maaaaad."

-Erf C.

You get what you pay for / It may be worth it

[GSearle]

This poses some interesting problems, along with some possibilities as well.

First of all, you can't point it. It has to point straight up! But what do you want for the price? They might be able to make a movable target like the one on the Arecibo dish, but then you still only get a few degrees of pointability. For the price, though, you could build lots of them and plant them at different latitudes, essentially getting full-sky coverage as the Earth turns. Now all we need is a little artificial gravity...

Mercury is toxic and it evaporates. They mentioned a "resin coating" in the article. Perhaps this solves the evaporation problem. How do they keep miniscule air currents from causing even the littlest ripple? The platform is spinning, which will cause some air turbulence.

Hey, I wonder if "adaptive optics" could be applied to this? It is a flexible surface. How could this be done? Electric currents and magnetic fields, perhaps?

Re:Is sharing so bad?

[ptomblin]

First, way to go jamie. Too bad you didn't apply for a patent. :)

Nice try, but according to the referenced article:

The concept of LMTs can be mapped back to the 18th century. Experiments that utilized the concept were conducted in the 1800s and the early 1900s, but the results were disappointing.

A little hard to patent a technology that is dead obvious (yes, I thought of the same idea when I was a kid too) and has been experimented with since long before you were born. Unless it's software rather than technology, in which case the patent office will grant you a patent immediately. :-)

This was actually talked about in Simpson case

[Vassily Overveight]

There were some people who wanted to find out if the NRO (National Reconaissance Office) had any photos of Nicole Brown's neighborhood at the time the murders were taking place. They wanted to see if OJ's car was there. I don't know if NRO even answered the request, but no photos were ever forthcoming.

I suspect that with the new commercial services that don't have the classification issues, we'll be seeing satellite photos used routinely in both civil and criminal matters.

Re:Dangerous??

[technos]

Oh, come on! The health hazards of liquid mercury are not nearly as bad as you may have been led to believe! I would rather see children play with liquid mercury in science class once a week then spend time in classrooms sprayed with Dursban insecticide and disinfected with single-agent antimicrobials!

Re:Trademark Infringement

[hanway]

TransAmerica's probably a walk in the park compared to the International Olympic(26USC0001) Committee. I suppose the picture of the Olympic(26USC1234) Stadium in Sydney probably violates some kind of exclusive broadcast rights. The next logical step will be the IOC's lawyers to "cease and desist" flying satellites over the Olympic(26USC9876) venue.

Hi-Rez press/media versions of pictures

[Smack]

A little know secret of the Space Imageing site is that you can pretend you're the media and get MUCH better versions of the images.

http://www.spaceimaging .co m/ikonos/anniversary/media.htm

Like that pretty 1800x1800 Olympic stadium image? How about a 3090x4516 San Fran image? (watch out, it might crash Netscape)

Just watch out if you don't have a nice pipe. Let's see if spaceimaging can handle it.

Mercury Telescopes are an old idea.

[Archeopteryx]

This was a topic in the series of books called "Amateur Telescope Making" published by Scientific American back in the '30s. The problems of old are;

1. It is a "Zenith transit" instument; It can only look staight up without a sidereostat or similar device of flat mirrors that removes much of the economy of this method.

2. Tiny disturbances make ripples larger than one-quarter wavelength of yellow light. This messes up the image a lot. Modern technology can finally solve this problem with feedback loop motion contols and etc.

3. Mercury is expensive. So one needs a cavity that is very close to the final mirror surface such that only a film is required.

4. Mercury is a hazmat and evaporates over time.

It's nice to see this old dog hunting again, though. This isn't the first time and not likely to be the last time.