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1. ### Quick check on telescope optics calculations please

Homework Statement A Cassegrain telescope has a 500mm diameter , a focal length of 5000mm and a central obstruction of 80mm diameter. Calculate: 1) the magnification with a 25mm eye piece 2) the light gathering power compared to aye of 5mm in diameter 3) the angular field in the sky if the...
2. ### Dark matter density calculation

Thanks a lot for you reply. Yes thhe question also asked us to compare the the mass of dark matter within the Solar System with the mass of normal matter? If iVe applied everything correctly then the answer I got for rho= 3v^2/4gPir^2 =2.77*10^-21 gave us a mass of =3.8*10^19 Kg...
3. ### Dark matter density calculation

Homework Statement We have been asked to calculate the density of dark matter in the solar system. I've used the following equation: Homework Equations rho= 3v^2/4gPir^2 The Attempt at a Solution V = 2.2*10^5 speed of solar system orbit around the galaxy G = 6.67*10^-11...