Solar Eclipses

iOS

Our iOS app includes the following solar eclipse features (version 4.12 or later):

• Solar eclipse events in the events list
• Eclipse paths for the 14 Oct 2023 and 8 Apr 2024 eclipses
• An eclipse progress indicator graphic
• A full eclipse simulator

Solar eclipses in the Events List

To view the Events List, tap the date at the top of the Map screen, and then scroll down. You can choose the calendar year for which events are shown by changing the selected date. In this example, I have set the date to Apr 1, 2024, and the events list shows events from that date forward, including the Apr 8, 2024 total solar eclipse:

You can tap the event to set the date to Apr 8. When you dismiss the Events page, the date will show the date of the eclipse.

Eclipse maps

If you set the date to either Oct 14, 2023 or Apr 8, 2024, you will see the path of the corresponding eclipse displayed on the map. If you don't see the eclipse path, try:

• Zooming out
• Moving the red pin to location in North America to ensure that you're in the correct time zone
• Adjusting the time of day
• Ensure you have updated to version 4.12 or later

The pink lines indicate the path of totality or annularity - you will observe a total eclipse or the full 'ring of fire' if located anywhere in this path.

The purple lines show areas where a partial eclipse is visible. The farther you are from the central line, the lower the magnitude of the eclipse, i.e. the smaller the overlap of Sun and Moon. The partial limit lines show lines of equal eclipse magnitude starting at 0.8 for the lines nearest the central path, and then 0.6, 0.4, 0.2, and finally the northern and southern limits of the partial eclipse:

Eclipse Progress Indicator

Also shown in the screenshot above is the eclipse progress indicator. This is displayed only at times when a solar eclipse is occurring at the location of the primary red map pin.

If you have selected the date of a solar eclipse, but don't see the eclipse progress indicator, that is because there is no eclipse visible at the location of the red pin, or that eclipse is not in progress at the selected time of day (or both). Try adjusting the pin location and/or the time of day.

The black circle represents the Moon and the white circle the Sun. The background of the graphic darkens as the time nears the moment of maximum eclipse.

Eclipse Simulator

You can tap the eclipse progress indicator to open a full eclipse simulator view. The simulator allows you to explore detailed times for the eclipse contacts (e.g. C1, start of partial eclipse, C2, start or total or annular eclipse, etc.), view the instantaneous magnitude and obscuration, and get a clear sense of how the eclipse is likely to appear

Controls

Use the controls to adjust the time shown by the simulator:

Tapping one of the Contact controls will set the time of the eclipse shown as follows (described from left to right):

• C1 start of partial eclipse
• ·  the midpoint between C1 and Max eclipse
• ◆ the 'diamond ring' just before C2
• C2 start of the total (or annular) phase
• Max time of greatest eclipse
• C3 end of total (or annular) phase
• ◆ the 'diamond ring' just after C3
• ·  the midpoint between Max eclipse and C4
• C4 end of partial eclipse

The Playback controls are as follows (left to right):

• Play/pause
• ×1 - playback the eclipse in real time
• ×5 - playback five times faster than real time (good for total/annular phases)
• ×100 - playback one hundred times faster than real time (good for partial phases)

You cannot adjust playback speed while Play is enabled - hit pause and then change the selected playback speed.

The Time slider provides direct control over the selected time - move it left or right to move backward or forward in time. Note: changing the selected time here only affects the simulator - it does not change the selected time in the rest of the app

Displayed Information

The simulator displays the following information:

Some tips:

• The magnitude and obscuration are for the selected time - they are NOT necessarily the maximum values that can be observed (to view those, tap the 'Max' contact control)
• To quickly view the duration of totality or annularity at the selected location, tap the C2 contact control: the time until C3 represents the duration of totality.
• Certified eye protection is needed to view the Sun during ALL phases of ALL solar eclipses, EXCEPT during totality (C2 to C3) in a total eclipse. The warning symbol shows when eye protection (and a solar filter on your camera!) is required: tap for further information
• Delta-T is included to allow experience eclipse chasers to understand what value has been used to calculate the eclipse circumstances. If you don't know what this, you probably don't need to worry about it. If you'd like to know more, see here.
• Advanced users may be interested in the Parallactic Angle and Solar Physical Ephemeris

You may also enjoy our articles on solar eclipses.