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Lunar Lens Takes A Step Forward
palewook writes "A recent breakthrough increased NASA's interest in a lunar-based space telescope. Researchers combined an ionic liquid surface and a layer of silver which produced a favorably reflective mirror."
I guess these liquids are practically solid like ordinary glass.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
if they're spinning the mirror, then they're gonna need some serious engineering to produce a support that is vibration free.
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
The Lunar chicks are just gonna love this.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
Have to get to the moon first.
Meldroc, Waster of Electrons
The question I would ask is: would not this mirror have a very short lifespan as lunar dust covers/mixes with the liquid surface?
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Lunar ant civilization takes two steps back.
help me fix this "Terrible" karma, please!
Telescope points you!
El hombre polvo de la Luna Soviética te folla, el hombre polvo de la Luna Soviética te folla, the dustman of the Soviet Luna fuck you.
With the new waves technology, the nanosatellites don't need the Luna.
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What I think they should do is build a huge telescope array on the moon... several miles in diameter.
File under 'M' for 'Manic ranting'
What about the orientation of this telescope? I guess that if it works with gravity, it can only look up and cannot be rotated. Luckily the moon rotates one full circle per 28 days, but still you miss one dimension to cover the sky. You could use another normal mirror to point it wherever you like (like shown here) but then you will need an enormous normal mirror, let alone that you might nor be able to manufacture it with the same smoothness a liquid mirror has.
What are the advantages of putting this on the moon rather than in space? I suppose you don't need maneuvering jets, so can it can be sustained longer?
As an avid slashdotter, without any knowledge of the subject, I declare this useless.
Static electricity is one thing that keeps moving dust around on the moon. And then there's ejected material from meteor impacts (with gravity that low, stuff kicked up by meteors can travel quite far)
The Sun's rays melt the imperialian telescope!
It's not a telescope, it's an aluminium roof of a top-secret base!
No Moon Threaty Here!
"Yes, launch tons and tons of highly toxic quicksilver on a rocket to Moon. What could go wrong?"
Well I suppose killing all life on the Moon would violate the Prime Directive.
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
>> Well I suppose killing all life on the Moon would violate the Prime Directive.
c tion/067172052X.pdf)
"Mighty important, that lunar ecology."
("Fallen Angels", L.Niven, (c)Baen Books, http://worldlibrary.net/eBooks/Baen_Library_Colle
"It's time to take life by the cans." ~ Bender ("Bendin' in the Wind", ep. 3-13)
How much weight is it for 99.9744 meters x 20.1168 meters?
Why a rectangle and not a square or circle?
For each 1 kg of missile, it transports 7 grams of useful material.
For each 1 ton of missile, it transports 7 kg of useful material.
For each 100 tons of missile, it transports 700 kg of useful material.
Doesn't exist a telescope of weight 700 kg with enormous dimensions 99.9m x 20.1m
Atten: On July 5 of this year...America will blow up the moon.
That is all.
The American People, America, Earth
Ginga no Rekshiya Mata Each page.
>>Borra envisions a telescope with a liquid mirror measuring 66 feet to 328 feet wide.
> Anyone with any knowledge of telescopes will immediately see why astronomers are drooling right now.
Okay, now they can start drooling:
a telescope with a liquid mirror measuring 20.1168 m to 99.9744 m.
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Actually, BSD = Devil, Linux = penguins.
If it's spinning liquid, it will be a parabola, which is what you want, but it will only point in one direction. How can you get around that?
Apparently, the serious engineering has been done and you can have ripple free liquid mirrors. There's a picture of both a huge mirror and an image obtained from it.
It's too bad this article and all the references are published in non free magazines. The $18 to $30 cost per article is steep. When you consider that all of the actual research is government funded, the cost of the information itself should be zero.
Friends don't help friends install M$ junk.
And what environmental factors could possible cause that on the moon, which has no atmosphere or tectonic activity?
The haze and other problems caused by moon dust is well known. One of the principle causes is solar ionization. Without an atmosphere to disperse charges, the dust ends up floating around like your hair while touching a van de graph generator. The irradiation is intense enough to be part of the weathering process that created the dust in the first place. Micrometorites are another cause. Because the dust is charged, it sticks to everything it comes in contact with. Dealing with dust is a design problem for lunar landers. I'm not sure how they will keep it out of the works of any telescope. Any tent you make will have to be cleaned too but that might be easier than cleaning a spinning liquid.
It's too bad Nature is a non free publication. They probably deal with the issue or point to other non free articles. Because government money funds this kind of work, you would hope the public would enjoy the best presentation of the ideas without having to pay $30/article.
Friends don't help friends install M$ junk.
Would the freezing of the mercury really be that much of a problem? How about a system where the mirror is formed of molten metal, then allowed to freeze (requiring no additional energy to hold its shape). If it gets scratched, chipped, warped, or otherwise marred, heat it up and shape it again.
The down side of such a system would be that you would lose the ability to change mirror dimensions "on the fly", but I'm not sure they're doing that anyhow. Also the mirror makers would have to account for the contraction of the metal on freezing, but at least they have the ability to retry if they don't get it quite right, or if the secondary mirrors (which presumably will be the standard glass type) turn out to be imperfect.
I also believe a telescope with a liquid mirror would have to be a "transit telescope", always pointed straight up relative to the local pull of gravity. Transit telescopes can track objects by moving their secondaries around, but not very far off-axis, and at the cost of focus and sensitivity. A solid-Hg mirror would remove this restriction, though it would possibly be too massive to reasonably move it around. Without this ability, observations would be at the mercy of whichever way the scope was pointed at any given time, give or take a few degrees.
It also seems to me the dust problem is relatively easy to solve using a positive pressure system. Any amount of gas in the telescope enclosure will be positive pressure compared to what's outside. Either the enclosure will not leak (and dust will have no way in), or it will leak slightly, forcing dust away from the leaks anyhow. Then maintaining a clean mirror is as simple as pumping in replacement gas.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
UBC has a telescope whose primary reflector is a spinning liquid mercury mirror http://www.astro.ubc.ca/LMT. It forms a paraboloidal reflective surface, which is one of the optimal reflector shapes, but can only be aimed at the zenith. A larger (6m diameter) version is being constructed for installation at the same facility near Vancouver.
Smaller liquid-mirror telescopes were designed in the late 19th century, and a 51cm diameter example was built in the early 20th century (by Robert Wood) http://en.wikipedia.org/wiki/Robert_W._Wood. Wood's design suffered from intermittent ripples on the surface, but performed well at other times.
At least Canada is closer than the Moon, and easier to get to (not necessarily less inhospitable, of course).
Those who can make you believe absurdities can make you commit atrocities. - Voltaire