You do not have to be a magician to put the moon where you want it in your pictures.

In this article, I am going to reveal how you can use software to predict the exact moonrise time, direction, angles and phases. You can use this information, in combination with a simple Google Earth trick, to enhance your composition with a celestial display de extraordinaire.

Selecting a viable subject

Step1: Find the angular range of Moon Rise or Moon Set

Software: Heavenly Opportunity (Shareware)

When I decided to photograph the moonrise over the Golden Gate Bridge some time ago, I already knew that it must be possible to have the full moon rise over the bridge. Skip to the next step if you are as confident about your location as I was.

Heavenly Opportunity

Heavenly Opportunity is a software package to predict sunrise, sunset, twilight, moonrise, moonset and the azimuth, directions and phases. You can download a trial version from their website.

Open the software and pick a location from the drop down menu. You need to enter GPS coordinates for locations outside the US.

Easily finding GPS coordinates of any location

A simple way to find the coordinates is through Google maps. Simply browse to your desired location in Google maps, click the link button in the upper right corner and copy the address. It should look something like this:

Copy the link and paste it in a text editor.

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=machu+picchu,+peru&
sll=37.0625,-95.677068&sspn=50.51141,76.464844&ie=UTF8&ll=-13.163496,-72.545911
&spn=0.003824,0.004667&t=h&z=18

The latitude and longitude are the two numbers behind ll (not sll). I have marked them with bold characters. The first number is the latitude of your location. The second number is your longitude. In my example the two numbers are -13.163496 and -72.545911. Verify the numbers by entering them in the Google Maps search field.

Find the Azimuth range:

Now you need to go to the date setting in Heavenly Opportunity and use the right arrow to skip through the next couple of months. Jot down the minimum Azimuth and the maximum Azimuth for the moonrise and for the moonset.

Step2: Decide what angle you need

Next you need to determine the exact angle you require for your shot.

I highly recommend Google Earth to every photographer. I often use it to research a photo location, determine shadows, calculate distances, best times to photograph and other things. This time we will use it to determine the Azimuth of the moon. 

Zoom to your location (or use the GPS coordinates from Step 1). Now click on the ruler icon in the toolbar and set your ruler start point to the exact location you will be standing during the shot. Drag the ruler across your subject. The heading indicated in the ruler window is your Azimuth. If the Azimuth falls between the min/max angles previously determined for either moonrise or moon set, you should be able to get the photograph.

Finding a date and time for your adventure

Now you need to determine a time where the moon aligns for you. Go back to Heavenly Opportunity and start skipping days until you find a day that closest matches your angle, has a nearly full moon and has the moonrise time after the sunset so that it is dark enough.

In the example above, I determined that May 8th, 2009 would be a good time to photograph the moon from the Marin Headlands viewpoint. HO predicted the moonrise to occur 5 minutes after sunset and the angle is the exact angle I indicated in the screen capture of Google Earth.

You can also print out the exact altitude angle vs. time for the sun and the moon. This can be very useful if you need the moon in a certain position, like above a skyscraper or underneath a natural arch.

Unexplained Deviations

I shot the first picture from a different location further down the hill. The viewpoint area closes down after dark and I had to leave.

When I stood at the exact spot, I chose on Google Earth, I expected the moon to rise somewhere close to the left pillar of the Golden Gate Bridge. Compare the screen shot of Google Earth above for reference with the angle predicted by HO.

The second picture in this article shows the view I had from the same spot. The moon rose much closer to the right pillar. Currently I have no explanation for the discrepancy. I know that the images in Google Earth are just stitched Bitmap files and since the Earth is round need to be warped. This can cause some distortions, but I have no indication that this is what threw off my calculation.

As John, the author of HO, kindly pointed out, this deviation was basically just user error (see comments below). Unchecking "Adjust for magnetic declination" will make the result correspond better with Google Earth. This option is really useful if you have the luxury to be able to scout your location far ahead of time with a compass in your hand. Travel Photographers often have to rely on intelligence gathering sessions with Google instead. Thanks John and good luck to all of you moon photographers.