Explain what is meant by the Rayleigh criterion when attempting to resolve two point-like celestial sources.
An orbital observatory is designed to detect extreme-ultraviolet (EUV) radiation in the wavelength range of 6 nm6\text{ nm}6 nm to 24 nm24\text{ nm}24 nm.
Explain why this observatory must be located above the Earth's atmosphere. Describe one advantage this EUV telescope has in terms of image detail over a space telescope of the same primary mirror diameter designed for visible light.
Table 1 shows the design specifications of two proposed ground-based radio dishes.
TelescopeDiameter / mDish ShapeTelescope Gamma150sphericalTelescope Delta30parabolic \begin{array}{c|c|c} \textbf{Telescope} & \textbf{Diameter / m} & \textbf{Dish Shape} \\ \hline \text{Telescope Gamma} & 150 & \text{spherical} \\ \text{Telescope Delta} & 30 & \text{parabolic} \end{array} TelescopeTelescope GammaTelescope DeltaDiameter / m15030Dish ShapesphericalparabolicBoth telescopes are designed to detect a cosmic spectral line at a wavelength of λ=5.0 cm\lambda = 5.0\text{ cm}λ=5.0 cm.
Compare the performance of Telescope Gamma and Telescope Delta when observing the same faint, distant radio galaxy. Your comparison must include a quantitative calculation of their relative collecting powers.
