Altitude Chart and Time Control

The altitude chart shows the altitude of the sun and moon through the day (in Day mode), or the altitude of the moon and galactic centre (in Night mode), measured in degrees relative to the unobstructed horizon. A higher value corresponds to the body appearing higher in the sky. When the line falls below the horizontal line, the center of the body is below the horizon.

While panning left or right, the chart legend shows the azimuth and altitude of the displayed bodies for the indicated time (and date):

To adjust the selected time, pan left or right with one finger:

You can also tap left or right of the vertical current time indicator to move by ±1 minute.

The azimuth lines on the map adjust their position to match the time of day displayed on the chart legend.

By default, panning to the left advances time forward (i.e. the chart moves under the time indicator with your finger). If you prefer, however, you can reverse the behavior such that panning left moves backward in time. This is available in Settings.

You can swipe down on the Timeline to hide it, if desired. To reshow the Timeline, swipe up on the altitude chart.

Event Markers

The chart shows key rise, set and transit events for the current date. You can tap a marker to change the date/time to the corresponding event:

A Note on Altitude

The chart shows apparent altitude, that is, altitude adjusted for the effects of atmospheric refraction. The effect of atmospheric refraction is to appear to 'lift' the sun or moon in the sky slightly higher than they would otherwise be observed. The magnitude of the effect decreases with positive altitude.