Moonrise from Bernal Heights

I’m really pleased with this time-lapse video of tonight’s moonrise, but despite my tweet, I didn’t quite nail it.

I had an approximate time of moonrise (6:44 pm) from the World Time iPhone app. I pointed the camera east (that’s where things rise, right?), and started the time-lapse capture, one frame per second, for playback at 30 fps. The result lasts 42 seconds, so it captures 21 minutes of real time. The camera was misaligned by about 20 degrees to the south for the first five minutes (10 seconds of time-lapse). When I saw the first light of the moon rising out of frame, I was able to realign the camera to get it in frame  within a few seconds. Still, it’s a glitch I’d like to avoid in the future. So I searched for “moonrise azimuth calculator” and found the USNO Sun/Moon Azimuth calculator. I filled it out for San Francisco, California, October 12, 2011 and got, in part, this:

Astronomical Applications Dept.
U.S. Naval Observatory
Washington, DC 20392-5420

SAN FRANCISCO, CALIFORNIA
   o  ,    o  ,
W122 26, N37 46

Altitude and Azimuth of the Moon
Oct 12, 2011
Pacific Standard Time

          Altitude    Azimuth    Fraction
                      (E of N)  Illuminated

 h  m         o           o
. . .
17:40       -1.6        70.5       0.99
17:50        0.7        71.9       0.99  <-- I saw it rise here
18:00        2.4        73.4       0.99
18:10        4.2        74.8       0.99
18:20        6.0        76.2       0.99

Note that this calculator does not use Daylight Saving Time, despite the fact that it’s now in effect more than six months out of the year. I saw the first light of the moon peeking over the East Bay hills, just south of Mount Diablo, at right around 6:49 PDT. This table says the moon should have been about 71 degrees east of north, so now I have a skyline landmark to associate with 71 degrees: just south of Mount Diablo. This will help next time.

Altitude and Azimuth of the Moon
Oct 13, 2011
Pacific Standard Time

          Altitude    Azimuth    Fraction
                      (E of N)  Illuminated

 h  m         o           o
. . .
18:10       -2.2        65.7       0.96
18:20        0.2        67.2       0.96 <-- Tomorrow's moonrise!
18:30        1.7        68.7       0.96
18:40        3.4        70.1       0.96
18:50        5.2        71.5       0.96
19:00        7.0        72.9       0.96

Tomorrow’s moon will rise another few degrees further north, 67 degrees, at 7:20 pm PDT. Maybe right behind Diablo? That’s where I’ll be pointing the camera, hoping for more weather like this.

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