Astronomy Principles and Practice Fourth Edition.pdf

Problems—Chapter 9 111
Date (00 h ) Apparent RA⊙ Date (00 h ) Apparent RA⊙
June 21 05 h 59 m 41·s15 Sep 22 11 h 57 m 23·s07
June 22 06 h 03 m 50·s68 Sep 23 12 h 00 m 58·s59
Calculate the length of summer in 2000.
18. At the summer solstice and at the autumnal equinox the values of the equation of time are −1 m 27 s and
7 m 20 s respectively. Calculate the length of summer.
19. The longitude of Columbia University, New York, is 4 h 55 m 50 s W. The sidereal time at mean noon at
Greenwich on a certain day is 17 h 23 m 08 s . Show that on the same day when the sidereal time at Columbia
University is 20 h 08 m 04 s , the hour angle of the mean sun at the same place is 2 h 43 m 41 s .