(a) Calculate sidereal time at 11am on December 8th of any year.
(b) Calculate the Greenwich Sidereal Time when the local sidereal time on longitude 20 degrees (West) is 20h 45m.
I know from my notes that a Sidereal day is 4 minutes shorter than a solar day, so it's 23h 56 m.
I don't know if it's relevant but I know that Julian Day is the number of days since noon at Greenwich on 1st Jan 4713 BC.
At the December Solstice, the RA of the sun is 18h 00m.
The Attempt at a Solution
(a) At the December solstice, the RA of the sun is 18h 00m.
Rate of change per day at the same time is 4 minutes.
I don't understand my astronomy notes at ALL, so I'm very very shaky on my understanding of these concepts.
Thank you :)