Question 729266
Stars of magnitude m are visible through a telescope of minimum diameter d (in inches). the relationship is m(d) = 8.8 + 5.1 log d. 
Round your answer to one decimal place. 
1. a telescope with diamter 75 inches can detect a star of magnitude 
m(75) = 8.8 + 5.1*log(75) = 18.37
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2. a star of magnitude 10.6 can be detected using a telescope with lens
Solve: 10.6 = 8.8+5.1*log(d)
5.1*log(d) = 1.8
log(d) = 0.3529
d = 10^0.3529 = 2.2539 inches
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Cheers,
Stan H.