lets assume you know the eight planets and the sun. Ok on clear nights,out of the city and city lights,you can see the milky way from here you take the portion of sky imaged by a telescope. Then — using the ratio of the sliver of sky,ile unaangalia,to the entire universe (the distance as would be measured between Earth and the edge of the observable universe is 46 billion light.....hence calculate the diameter and that would be ratio) you can determine the number of galaxies in the universe. Pole kukuchanganyisha