Moonrise time and location prediction

This is an explanation on how to predict the exact location and time of a moon or sunrise. Since a telescope or a camera zoom lens have high magnifications, pointing your manually controlled telescope to the exact location of the moonrise is essential if you want to capture the moon as it rises above the horizon. Otherwise you might miss the first moments of the moonrise while you’re trying to readjust the telescope.

What you’ll need is:

• Stellarium. You can get it from here
• Google earth. You can get it from here.

Before you start you must find your observation location in Google earth and set the observation location in Stellarium to your coordinates. Your clock must be synchronized with Stellarium’s clock.

First I checked in Stellarium where the moon is going to rise. In my case it was somewhere around 115 degrees.

In Google earth I drew a line (using the path or line tool) from my observation location with a heading of 115 degrees.

I changed the view in Google earth so I look directly in the direction of the moon from my location.

I also took an image with my camera so I can compare the real landmarks with the rendered terrain.

I got the height of the highest point in my line of sight. I pointed the mouse to the peak so I can get the hight of the hill (813 m).

Then I drew a line from the hill to my observation location to check my distance (6430 m).

Then I calculated the angle of the hill from my position.  Sin(x) = height/distance =  813/6430 = 0.1264  ;  x = 7,26 degrees.

I checked the time the moon is at about 7 degrees elevation (I give myself some extra time to prepare the camera).

 I noticed the actual direction is 116.5 degrees so I rechecked the location in Google earth and made the appropriate adjustments. Since the hill top was fairly flat the adjustments where minor. Then I pointed the telescope to the same location by comparing the view from the telescope to the Google earth view and started taking the video a minute before the predicted time. 

You can see the results below

This works for sunrises but be careful not to point any instrument or look directly at the sun without using appropriate filters.

Thanks for reading :)

and clear skies!