1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Local Sidereal Time of Observation.

  1. Apr 18, 2010 #1
    1. An astronomer at the Dominion Astrophysical Observatory (DAO), located at latitude
    48° 31' N in Saanich, near Victoria, B.C., is studying the K2 III star N'3148°α Arietis. The equatorial coordinates of α Arietis are right ascension=2h 07 m 30s and declination of 23°29'

    If the astronomer starts an observing run 3 hours before α Arietis crosses the meridian, at what local sidereal time does the observing run start?

    2. Relevant equations


    3. The attempt at a solution

    I'm wondering if I just used the equation of if there is more comprehension involved. Would I take the hour angle to be -3h (since it east of the meridian) and add it to the right ascension of the star?
  2. jcsd
  3. Apr 18, 2010 #2


    User Avatar
    Science Advisor
    Gold Member

    Yep, that's about it. It's as simple as that. =)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook