A dust cloud with constant opacity,

A)The star 58 Eridani is a feint but naked-eye star similar to the Sun. Suppose that you are observing this star in the night sky without a telescope. Ignoring any interstellar extinction or atmospheric absorption, approximately how many photons per second arrive at your retina? Show all steps in calculation .  B) The Mid-infared Instrument (MIRI , camera and spectrograph ) on the James Webb Space Telescope operates in the band 5-28 µm . For 58 Eridani , approximatley how many photons per second can be used by this instrument ? Assume that MIRI takes all the photons from the full JWST mirror . Show all steps in calcultation .  Describe breifly two or three other factors which play a role in determining the sensetivitu of an instrument such as MIRI ?

Cas A SNR North Lobe Chandra ACIS image (M. Stage) region of spectrum-> 10* km/s (be sure to convert your answer to kilometers!) (Enter a positive value--if you get a negative answer ignore the minus sign.) 1000 100 Combine counts / Ang./ (0.964324 sq. arcsec) 10 1 0.1 Cas A Ms Spectrum from 4362.5 4458.5, region size 0.964324 sq. arcsec Silicon line werden der 5 10 20 Wavelength (Angstroms) The speed of the material ejected in a supernova can be measured by using the Doppler shift of the X-ray emission lines in its spectrum. The images above show real X ray data of the Cassiopeia A supernova remnant and a spectrum extracted from that data--you can see several emission lines including the silicon line near 6.6 angstroms (0.66 nm). If the emission line created by silicon normally has a wavelength of 0.6648 nm (nanometers), but is measured in the spectrum to have a wavelength of 0.6599 nm, how fast is the gas moving?

5... Calculate the fraction of time a spacecraft spends in daylight given a celestial body with a radius 5,709 km at an altitude of 686 km. Use the extreme case (minimum alpha) when the angle between the orbit plane and the direction of the sunlight is 0.