Moon Overhead and Underfoot
derekrusty
Posted 1/10/2013 8:10 PM (#608923)
Subject: Moon Overhead and Underfoot





Posts: 186


Location: Waconia, MN
So I am trying to do some calculations because I assumed that the moon overhead would be exactly half way between moon rise and moon set and that moon underfoot would also be exactly half way between these 2 as well, in opposite order of course. The data I see shows that overhead and underfoot are close to half way, but not exact. Does this make sense? I am going off of this website and while it seems accurate and legit, I am just unsure as to why it wouldn't be right between the two. Is there something I am not considering or factoring in? Thanks!

http://www.solunarforecast.com/solunarcalendar.aspx
jchiggins
Posted 1/10/2013 8:20 PM (#608925 - in reply to #608923)
Subject: Re: Moon Overhead and Underfoot




Posts: 1760


Location: new richmond, wi. & isle, mn
The moon rise time of day is always increasing day to day. That's the factor you're not considering
esoxaddict
Posted 1/10/2013 8:24 PM (#608929 - in reply to #608923)
Subject: RE: Moon Overhead and Underfoot





Posts: 8772


derekrusty - 1/10/2013 8:10 PM

So I am trying to do some calculations because I assumed that the moon overhead would be exactly half way between moon rise and moon set and that moon underfoot would also be exactly half way between these 2 as well, in opposite order of course. The data I see shows that overhead and underfoot are close to half way, but not exact. Does this make sense? I am going off of this website and while it seems accurate and legit, I am just unsure as to why it wouldn't be right between the two. Is there something I am not considering or factoring in? Thanks!

http://www.solunarforecast.com/solunarcalendar.aspx


Maybe one side of the horizon is higher than the other??
'ya got me, man. I'm stumped!
Slow Rollin
Posted 1/10/2013 8:32 PM (#608933 - in reply to #608929)
Subject: RE: Moon Overhead and Underfoot




Posts: 619


maybe when the earth tilts a certain way it brings moon overhead
derekrusty
Posted 1/10/2013 8:48 PM (#608939 - in reply to #608925)
Subject: Re: Moon Overhead and Underfoot





Posts: 186


Location: Waconia, MN
jchiggins - 1/10/2013 8:20 PM

The moon rise time of day is always increasing day to day. That's the factor you're not considering


I do realize that, but in calculating each day, I am counting the amount of time between moon rise and moon set, then dividing that amount of time in half and comparing that the moon overhead and underfoot times listed on the site above. It is close, (some days closer than others), but never exact.

I bet Tom Gelb knows the answer! Tom, you on here?

Side note, just finished his book, very good!
jchiggins
Posted 1/10/2013 9:06 PM (#608943 - in reply to #608923)
Subject: Re: Moon Overhead and Underfoot




Posts: 1760


Location: new richmond, wi. & isle, mn
all celestial orbits are eliptic so linear equations arent going to work. einstien could explain it better . just stick to the charts and fish whenever you can.