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Optical Telescope Arrays by Amateur Astronomers?
fl_ska asks: "I recently attended a meeting of local amateur astronomers in my area known as The Local Group of Deep Sky Observers. After being blown away by views of the Orion Nebula and such, I got to thinking about the state of modern amateur astronomy. For instance, I recall reading about a project to link multiple optical telescopes so as to approximate the light-gathering capacity of a much larger telescope, a so called 'array of optical telescopes.' With the advent of the Web, it seems like it would be relatively easy to coordinate such a project via some central server which could then process and link images for all to view. I was wondering if there were any amateur astronomers out there who were possibly working on a similar project?"
"Could the same gains that were achieved with grid-computing be found in amateur telescope arrays? What kind of issues would be relevant to the problem of organizing such a project? Also, I once read about a way to correct for atmospheric perturbation by way of creating an artificial point of light in the upper atmosphere and, in real time, analyzing how the atmosphere acted on it. Could such a method be utilized by amateurs and would it detrimentally affect the original data set?"
In the grid computing analogy, 100 cheap computers working together can produce the equivalent output of one computer 100 times as powerful. The same cannot be said of amateur telescopes working together. For a simplistic example, adding two images both of signal-to-noise 10:1 will result in an image with best signal-to-noise of 20:1.4, which is not twice as good as two single images. Modern large-scale telescopes are so great that all the amateurs in the world would have trouble stitching together a comparable image. Best for amateurs to concentrate in areas the big boys can't match, and not try to win the signal-to-noise (or deep image) game.
"Eve of Destruction", it's not just for old hippies anymore...
There is a project in the U.K. by professionals to do this (Cambridge Optical Aperture Synthesis Telescope). This gives a pretty good description of what is necessary for setting up an optical array. Note the combining building, which is where the light path lengths are matched. The main thing is that the images are formed from light that arrives at the telescopes at the same moment. With radio frequencies, the signal can be recorded on tape, along with a time hack, allowing for multiple signals to be combined after the fact. I don't believe there is a way to do that with light.
In grid computing, 100 cheap computers working together produce the output of five or six computers. They have the storage capacity of 100 computers, but the interconnect speed kills everything else, except maybe some useless benchmark designed to show how cool grid computing is and get more grants.
Placing an artificial point of light in the upper atmosphere may not be feasible, but why not have the ISS take some measurements so we know the properties of light emitted by the points of light that are already there? Then we'd have some known reference points for correcting for the atmosphere's effects.
Give me my freedom, and I'll take care of my own security, thank you.
OTOH, that still leaves the issues of maching grids and all that fun stuff.
A Shadeless room is a brighter room.
Other people have pointed out the problems with combining many small optical telescopes to get a deep image, but deep images tend to cover small fields. There's a lot of sky that goes unobserved every night, and moving or transient phenomena are easily missed. Why not coordinate your team to try to cover as much of the sky as possible? This could be great (depending on brightness and telescope size) for near Earth asteroids, optical SETI, (super)novae, optical counterparts to gamma ray bursters, and other things that go bump in the night. Plus the eyes and brains of amateurs are a distributed processing system for picking out the interesting stuff. I hope there's enough amateurs who are tired of taking yet another image of that nebula everyone else has taken images of, that this catches on.
If we were ants living on a Rubik's cube, differential geometry would be a little more confusing.
Actually, the gains for resolution wouldn't be worth it ... but for COVERAGE they would be. Imagine doing a full-sky survey with 8" scopes every few months or even weeks.