More Venus fun tomorrow


If you would like some more fun and improve your understanding of celestial coordinates you can use this Venus crossing as a good way to understand the concept of right ascension (RA). We know that Venus crosses the meridian at 1538 tomorrow here. 1538 is mean solar time, not what is used for astronomy which uses sidereal time. The math is too complex for conversion here but fortunately we have someone who has already done it in a calculator. Go to this web site and enter the information for local time conversion into the top of the form. You need the date, local time and time zone (-4 for here). Remember it is daylight savings time so we are 4 hours back from UTC. You also need the longitude for your location. Virginia Beach is -76 00 56.800 . When you enter the data look down and find the sidereal time. It should be 02 hours and some minutes. Now go to an astronomy program like Sky Safari or Sky tools. Notice the location (RA DEC) of Venus. The RA should be very close to the sidereal time you calculated. That is how RA is used for astronomical coordinates of objects. It gives you a better feel for how the sky is mapped. Here is the calculator site: