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Russian 6-m. Nasmyth focus platforms Problems: 17-ton mirror has thermal time constant of a few days; location based on politics. Note alt-az mount. Enormous telescopes of the Future. TMT = Ten Meter Telescope (US) OWL = Overwhelmingly Large telescope, 100m. The rest of the spectrum.
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Russian 6-m • Nasmyth focus platforms • Problems: 17-ton mirror has thermal time constant of a few days; location based on politics. • Note alt-az mount
Enormous telescopes of the Future • TMT = Ten Meter Telescope (US) • OWL = Overwhelmingly Large telescope, 100m
The rest of the spectrum • Space-based observatories needed • Radio requires special telescopes
Russian 6-m • Nasmyth focus platforms • Problems: 17-ton mirror has thermal time constant of a few days; location based on politics. • Note alt-az mount
Compton Gamma Ray Observatory (GRO) • Mission now over
SIRTF = Space Infra-Red Telescope Facility • launched a year ago • Renamed the Spitzer Space Telescope
James Webb Next Generation Space Telescope • > 20-ft diameter • Named after 2nd NASA administrator; built by TRW • L2 Lagrange point for Earth-Sun system (thus 106 times closer to us than sun – mass ratio…), or 940,000 miles from us. (Sun-stationary)
Karl Jansky’s Rotating Antenna (Bell Labs, 1931) Saw a sidereal period (~23h56m) signal
Typical Radio Astronomy Telescope Why so large? ….
Resolution of telescopes • Angular resolution depends on telescope diameter (D) and signal wavelength (λ): Rayleigh criterion: Θmin ~ λ / D
Some numbers … For optical wavelengths, Θ in arc-seconds, and D in inches it works out to Θmin ~ 4.5 / D Example: for your 8-inch telescopes, Θmin ~ 4.5 / 8 = 0.56 arc-sec (note signs…)
Schematic Today: a computer