I do I track the position of the moon in the sky?

Question

If I am in BC where approximately should I look in the sky to view the moon?

Answer 1

Here's some low-precision formulae for the main lunar perturbations that I built into a program I wrote many years ago.

JD is the Julian date for which you want to predict the moon's geocentric position in right ascension (RA) and declination (dec). Your position on Earth's surface will generally impart a bit of inaccuracy to the prediction.

T = [ (JD+1) - 2451545 ] / 36525

L = 218.32 + 481267.883 T
L = L + 6.29 sin( 134.9 + 477198.85 T )
L = L - 1.27 sin( 259.2 - 413335.38 T )
L = L + 0.66 sin( 235.7 + 890534.23 T )
L = L + 0.21 sin( 269.9 + 954397.70 T )
L = L - 0.19 sin( 357.5 + 35999.05 T )
L = L - 0.11 sin( 186.6 + 966404.05 T )

B = 5.13 sin( 93.3 + 483202.03 T )
B = B + 0.28 sin( 228.2 + 960400.87 T )
B = B - 0.28 sin( 318.3 + 6003.18 T )
B = B - 0.17 sin( 217.6 - 407332.20 T )

u = cos(B) cos(L)
v = 0.9175 cos(B) sin(L) - 0.3978 sin(B)
w = 0.3978 cos(B) sin(L) + 0.9175 sin(B)

RA = Arctan { v / u }
If u < 0 then RA = RA+pi
If (u > 0) and (v < 0) then RA = RA + 2 pi
Adjust RA to hours, minutes, seconds.

dec = Arctan { w / sqrt(1 - w^2) }
Adjust dec to degrees, minutes, seconds.

That should do you for finding the moon's position with respect to the stars. I'll leave it up to you to convert to your local azimuth and elevation.

I'm not sure where the perturbation curve-fits came from. They might be from Jean Meeus, or they might be from an old copy of the Astronomical Almanac.

Edit: I just now found a page that shows the same low precision algorithm that I used. It's at
http://bodmas.org/kepler/moon.html

You can calculate the Julian date (JD) from the calendar date as follows:

Y = the four-digit year
M = the number of the month
D = the day of the month

if (M=1) or (M=2) then N= -1, else N=0

JD = 1461 (Y + 4800 + N)
JD = JD div 4
JD = JD + 367 (M - 2 - 12N) div 12
JD = JD - 3 [ (Y + 4900 + N) div 100 ] div 4 - 32075 + D

Or you can just use somebody's handy conversion on this page:
http://wwwmacho.mcmaster.ca/JAVA/JD.html

Answer 2

Being very close to Full Moon, it rises in the East just as the Sun sets in the west. Later in the evening, the Moon is towards the Southeast. At midnight, it will be due South, very high.

Later in the week, it will rise later than sunset (almost one hour later every night) so that by Thrusday of Friday, you should see it in the daytime (in the morning) towards the West.

Answer 3

We're near Full Moon so the Moon is in the sky nearly all night long. It's also by far the brightest object in the night sky. Unless you're blind or the sky is overcast, it would be hard to miss it!

Answer 4

The Moon is pretty bright. If it is up and the sky is clear, you don't need instructions; it is pretty obvious. It is asking like where to look for the Sun.

Answer 5

What is BC? British Columbia? And like Geoff said, you can't really miss it.

Answer 6

Look eastward at sunset