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Methods to Remove the Deleterious Effects of the Earth’s Atmosphere on Astronomical Measurements

-- | May 23, 2016

Question: Would it be possible to improve astronomical seeing on earth using a circular surrounding array of lasers pointing directly into space, which surround the ground based telescope and ionize the air and/or somehow move it away from within the created cylindrical column of laser beams (extending from ground level into space), so that the air between the telescope and space is pushed out of the way? If it is not possible to create a total vacuum, then could the lasers be used to somehow create a “less hospitable” area for air to exist, or is at least be “massaged” in such a way to become more predictable in its turbulence pattern, and thereby easier to cancel out the atmospheric distortion using existing computer programs. (Something like light passing through a polarization filter, becomes well defined, except for turbulent air.) — Mike

Answer: I can tell you for a fact that every astronomical observer has tried to come up with a scheme to do just what you envision while trying to observe through the Earth’s fluctuating atmosphere. Even though in theory elimination of the atmosphere above an observatory would be the perfect solution, I think that it is rather impractical as you would have to control that vacuum in the midst of the atmosphere not above the observatory. A more practical approach would involve a system whereby the Earth’s atmosphere was made more stable. If it were just a constant slab above an observatory then correcting for its effects would be relatively easy. The current state-of-the-art in atmospheric correction involves monitoring the state (column and variations) of the Earth’s atmosphere to correct for its effects on both optical and radio observations. The monitoring system is often a measurement system that is sensitive to a particular component of the Earth’s atmosphere that is the biggest “trouble maker”, such as water or oxygen. These systems are reasonably effective at limiting the deleterious effects of the Earth’s atmosphere on astronomical measurements.

Jeff Mangum

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