1. The problem statement, all variables and given/known data Astronomer observing the sky with a small telescope by hole at the observatory in the middle of dome (lens diameter is much smaller than the diameter of the dome). Calculate the maximum time when astronomer can still observe objects near the celestial equator, without having to rotate the dome. Which side of the world will it be? Diameter dome: 5m, width hole: 1m, latitude: +50 ° 2. The attempt at a solution - circumference of the dome: dπ = 15, 7 m; it is 360° = 23h 56m 4 s = 86 164 s - width hole is part of circumference: 1m; it is 22, 9° of dome = 5488 s = 1,5 h So, the result is 1,5 h. I did not use latitude! Is it wrong? However, the question ,,Which side of the world will it be?" Hmmm, I don't know :-( I think it is west, but I can not explain why. Can you help me? Thanks and sorry for my bad English.