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1_ Standard star with magnitude ms = 15 produces current i= 5ma.
Target star with magnitude mt = 10 what amount current will produce?
2_ A star produces 400 count per second. What is integration time in order to get accuracy of measurements 5% .
3_ From the spectrum taken of a star Hβ (4861 A°) exhibits a blue wave length displacement of (0.69 A°) what is relative velocity approach of the star?
4_ Given tow telescopes A and B, the diameter of the telescope A 1000mm, calculate the diameter of the telescope B if the limiting magnitude of A and B are 16.m4 respectively neglect any light losses. Calculate the limiting magnitude of A one_fifth (1/5) of the incident light is lost .
5 _ When performing photoelectric photometry with a particular system, it is noted that a 4_th magnitude star generation time required to achieve photometric accuracy of 2% on a 9_th magnitude star?
(Assume the background radiation count to be zero).
What would be integration time for the background radiation if it has count rate 1000 photon/sec
6_ A diffraction grating with a ruling 500 lines. Mm-1 is 50mm in length and is use in second order as disperser in a spectrometer. What is the minimum radial velocity that could be detected by Doppler shift ?
What is theoretical resolving spectral power of the instrument?
7_ The surface temperature of the sun is ( 5800k) and its radius is 7.10 km What is total luminosity of the sun ?