The equation of time is 12m 00s and the mean Sun is ahead of the apparent Sun. If you are on the central meridian of your time zone, at what zone time will the apparent Sun cross the meridian?
• Equation of time: relationship between mean Sun and apparent Sun • Meaning of "mean Sun is ahead of the apparent Sun" in terms of when each crosses the meridian • On the central meridian of a time zone, how local mean time relates to zone time (ZT)
• If the mean Sun is ahead, does it cross your meridian earlier or later than the apparent Sun? Sketch a simple time line: which one is "in front"? • At the central meridian, what is the zone time when the mean Sun is on your meridian? Then adjust that time by the equation of time to find when the apparent Sun crosses. • Should the apparent Sun’s meridian passage be before or after 1200 ZT in this situation, and by how many minutes?
• Be clear on the sign convention: when the mean Sun is ahead, the equation of time is applied with which sign? Check your Nautical Almanac convention. • Verify that at the central meridian, local mean time (LMT) at meridian passage of the mean Sun is exactly 1200 ZT. • After applying the 12m 00s difference with the correct sign, confirm whether the result matches any of the listed clock times.
No comments yet
Be the first to share your thoughts!