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- Active_surface abstract "An active surface is a surface of a radio telescope that is under active computer control of its shape.Large (more than 10 m in diameter or length) radio telescopes always bend during operation, due to their enormous weight and the fact that even the strongest materials are not perfectly stiff. This bending, in the range of a few millimetres, does not affect low frequency operation much, but dramatically reduces the efficiency of the telescope at higher frequencies where the wavelengths are comparable to the distortion. Typically, the efficiency of a telescope drops appreciably when the deviation from the desired shape is more than 1/10 of the considered wavelength. An active surface uses numerous small actuators to move the surface panels with respect to the underlying frame, and thus maintain the correct shape.An active surface can try to compensate for many different types of errors. The first is gravity - this is simplest since previous measurements, or even a mathematical model, can be used to predict (and correct) any bending. More difficult is correction for wind and thermal errors, since these require measuring and correcting in real time.Some examples of active surfaces are:Green Bank TelescopeLarge Millimeter TelescopeSardinia Radio TelescopeNoto Radio Observatory".
- Active_surface wikiPageExternalLink p0639.pdf.
- Active_surface wikiPageExternalLink abs_all.jsp?arnumber=1373995.
- Active_surface wikiPageID "19918926".
- Active_surface wikiPageLength "2336".
- Active_surface wikiPageOutDegree "8".
- Active_surface wikiPageRevisionID "706101050".
- Active_surface wikiPageWikiLink Category:Astronomical_imaging.
- Active_surface wikiPageWikiLink Category:Astronomical_instruments.
- Active_surface wikiPageWikiLink Category:Radio_astronomy.
- Active_surface wikiPageWikiLink Green_Bank_Telescope.
- Active_surface wikiPageWikiLink Large_Millimeter_Telescope.
- Active_surface wikiPageWikiLink Noto_Radio_Observatory.
- Active_surface wikiPageWikiLink Radio_telescope.
- Active_surface wikiPageWikiLink Sardinia_Radio_Telescope.
- Active_surface wikiPageWikiLinkText "Active surface".
- Active_surface wikiPageWikiLinkText "active surface".
- Active_surface wikiPageUsesTemplate Template:Cite_conference.
- Active_surface wikiPageUsesTemplate Template:Cite_journal.
- Active_surface subject Category:Astronomical_imaging.
- Active_surface subject Category:Astronomical_instruments.
- Active_surface subject Category:Radio_astronomy.
- Active_surface hypernym Surface.
- Active_surface type Bone.
- Active_surface type Instrument.
- Active_surface type Instrument.
- Active_surface comment "An active surface is a surface of a radio telescope that is under active computer control of its shape.Large (more than 10 m in diameter or length) radio telescopes always bend during operation, due to their enormous weight and the fact that even the strongest materials are not perfectly stiff.".
- Active_surface label "Active surface".
- Active_surface sameAs Q4677590.
- Active_surface sameAs m.04qb2k7.
- Active_surface sameAs Q4677590.
- Active_surface wasDerivedFrom Active_surface?oldid=706101050.
- Active_surface isPrimaryTopicOf Active_surface.