Sky Light Pro

This is a very useful app for those who spend time in the outdoors for recreation or work. With this app you can quickly and easily view the computed rise and set times and positions of the sun and moon, anywhere, anytime. No internet connection is required since the app includes all the data and formulas required, however it does use your phone's GPS so that the information reported is correct for your current location.

When you open the app, it automatically shows the current positions of the sun and moon. The white dotted line indicates the horizon where the sun and moon rise and set. The red dotted line indicates the beginning and end of nautical twilight. EENT (End of Evening Nautical Twilight) represents the time beyond which it will be completely dark at night, while BBMT (Beginning of Morning Nautical Twilight) indicates when the very first light of dawn will start appearing.

You can use the slider at the bottom of the page to animate the sun and moon through the sky over the course of the day. You can also compute the positions of the moon and sun for any given date using the calculate and forecast pages.

To help locate the moon or sun in the sky, you can use the built in compass page which also shows you the azimuth or elevation angle as you tilt your phone upwards. If you use the compass to orient your phone to the north, then the sun and moon will appear in the sky at the positions indicated on the screen. There is also a setting on the preferences page to reverse this view for use in the northern hemisphere so you can point your phone to the south and see the moon and sun in their actual positions.

If you want to see how the phase or illumination of the moon will change over the month, you can also open the moon phase page and use the slider to animate the image of the moon. The moon phase and rise/set times are useful for planning night time activities where having good moon light is helpful, as well as finding out when complete darkness will be available if that is what you need.