Expert: Steven LJ Russo - 4/5/2004

Question
Hi,

I have been studying the relationship and movements of the Earth, Sun, and Moon. Their relative positions to each other over time in particular. As a reference marker, I am using the Terminator(sun line) on the Lunar surface, since it is viewed from the Earth, but determined by the relative positions of all three objects.

I have the Planetarium software by Fogware Publishing. It is relatively cheap software, but it seems to do the job. Using this program I have determined the longitudinal position of the Terminator on the moon's surface to be at these positions on these dates and times:

7-20-1969   at 4:17 pm EDT  the Terminator was at about 18 degrees East.
11-19-1969   at 1:54 am EST  the Terminator was at about 24 degrees West.
2-5-1971 at 4:18 am EST      the Terminator was at about 26 degrees West.
7-30-1971 at 6:16 pm EDT  the Terminator was at about 10 degrees West.
4-20-1972 at 7:34 pm EST  the Terminator was at about 8 degrees West.
12-11-1972 at 2:55 pm EST  the Terminator was at about 17 degrees East.


The problem is, I'm not sure I'm doing this right.

Would you be able to help confirm or correct these findings?  Or perhaps direct me to a good source for such information?

Thank you very much,

Ed


Answer
Ed:

I would imagine that you are on the right track, but here is how you can figure it out.  Using your progran, take a look at how the moon looked on those dates, then get hold of a Moon Map showing the Longitude and Latitude and see where the terminator may be on the equator.  However, the moon's longitude is not measured like the Earth's; E or W of a prime meridian.  It is USUALLY measured in degrees form zero - 360.

Now however, you have peaked my curiosity.  The 6 dates you chose are not at random.  They are of course the dates of all the Apollo Manned Lunar Landings.

Just curious.

Steve