Local Sidereal Time of Observation.

AI Thread Summary
The discussion focuses on calculating the local sidereal time (LST) for an observation of the K2 III star N'3148°α Arietis at the Dominion Astrophysical Observatory. The observer is starting the run three hours before the star crosses the meridian, which requires understanding the relationship between hour angle (HA) and right ascension (RA). The equation LST = HA + RA is applied, with the hour angle being -3h since the star is east of the meridian. The conversation emphasizes the simplicity of the calculation while confirming the correct approach to using the equation. Overall, the discussion highlights the practical application of astronomical calculations in observational astronomy.
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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?


Homework Equations



LST=HA+RA


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?
 
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Yep, that's about it. It's as simple as that. =)
 

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