if the arecibo radio telescope was fitted with mirrors focusing to one point at night, could it see stars good?
Sunday, December 19th, 2010 at
8:21 pm
in more words, if a dish like mirror telescope could focus its image to a common center with a surface that collects the inmages and is able to proyect them onto a half sphere screen.
Is this posible or not?, please explain.thanx
idea to add, it not mirrors, could the images be collected digitaly with hundres of cameras focusing to one point?..just a thought...
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US $2.95
Not really, as the dish is spherical, not parabolic, so the image wouldn’t look good.
It can get away with a spherical reflector as it is a radio telescope and the spherical aberration can be accounted for.
This is pretty much exactly what optical telescopes do!
If you take a look at a telescope like the 200″ Hale telescope at Mount Palomar Observatory, you’ll see that the optical design resembles pretty closely the design of the the Arecibo radio telescope, or really any kind of radio telescope.
The reason is simple – both are doing the same thing, the only difference is the frequency of the electromagnetic radiation.
Unfortunately, when you vastly increase the frequency of the light/radio that you want to look at, it means that the curve in the telescope has to be even more precise. In a visible telescope with a standard mirror the curve is accurate to within -FAR GREATER- than a human hair. On the scale of 1000th’s of a human hair! With a radio telescope, the curve only has to be accurate within an inch or two. This means that if you just put a bunch of mirrors on the Arecibo telescope, the image you’d get out of it would NOT be very good.
Many of the large telescopes built in the last 30 years have adaptive optics. Do a search on … never mind:
http://www.google.com/search?sourceid=navclient&aq=7&oq=adaptive+opt&ie=UTF-8&rlz=1T4GPCK_enUS400US400&q=adaptive+optics+history
Arecibo was configured to be a RADIO telescope, not an optical telescope.
Trying to convert a radio telescope to optical is futile. Optical telescopes must be designed with optics in mind from the very start. The tolerance of an optical surface is measured in nanometers; the tolerance of a radio telescopes reflector is measured in millimeters. We are building bigger and bigger optical telescopes all the time, and the result is higher resolution. Optical telescopes have a long way to go to match the resolution of the VLBA radio telescope, whose resolution is measured in microarcseconds.