[SOLVED] Telescope Resolution 1. The problem statement, all variables and given/known data An Active Galactic Nucleus (AGN) is fueled by gas and dust in a rotating accretion disk that is streaming onto a supermassive black hole in the center of the galaxy. These accretion disks are typically a few pc in diameter and are best detected at long wavelengths (to penetrate the dusty envelopes of these galactic centres). One of the nearest AGNs is 3.3x106 pc from Earth and is powered by an accretion disk that is 2 pc in diameter. a) What size telescope would you need to resolve this accretion disk at a wavelength of 10 μm and also at 21cm? 2. Relevant equations p(′′) = 1/D(pc) θ (") = 2.5 × 10^5 λ/D 3. The attempt at a solution The only way I can see to find this is to use the parallax equation to find the size of the accretion disk in " and then use the angular resolution formula to find the telescopes diameter using each wavelength. But I am not sure if this will work considering that seems like an improper use of the parallax formula. Could someone give me a hint as to whether Im going in the right direction?