[GWN] Lunar Calendar?

[Tessa]

Hi,
Can anyone explain the lunar calendar? I looked at the menu but it really 
doesn't do an adequate job of explaining some things and this is one. What 
does one do with the lunar calendar? Does it give the phases of the moon or 
something? The manual doesn't say. Do I have to set the date for it, at 
present it's about a month behind the solar calendar. It's a neat item but I 
haven't a clue what it does LOL.
Thanks
Tessa