The Date & Time view can be set to use the current time, or can be set to a specific time/date in the past or future. When set to current time, the chart view will update every second to show the current positions of objects in the sky.

Use Current Time keeps SkySafari's simulated time in sync with your mobile device's built-in system clock. When turned on, the sky chart updates to match real time every second.

Setting the Time and Date

To change the simulated date:

• iOS users touch the Time and Date tab at the top of the screen, then use the calendar to set the desired date.

• Android users tap the Set Date button to select a new date.

Time Presets:

There are buttons below the picker to allow you to quickly set the time to specific events such as Sunset, Moonset, etc. The exact time of these events will differ based on your location and the simulated date.

Automatic Daylight Saving Time: This switch turns the automatic daylight saving time (DST) correction on and off. When the switch is on, SkySafari automatically determines whether DST is currently in effect based upon the date and your simulated location. SkySafari displays a message below the switch, telling you whether it thinks DST is currently in effect for your simulated date and location.

Governments often change the rules for daylight saving time, so SkySafari's automatic DST option may not work. If this happens, you may turn off Automatic DST, and instead add one hour to your Time Zone setting, in the Location view.

Advanced Options

In SkySafari Plus and Pro, there are additional options for setting the date and time. The standard iOS date/time controls do not easily let you pick a date more than 100 years in the past or future, or to the nearest second. Select the Advanced tab to see some new options which let you enter the time more precisely and in alternate ways.

With the Advanced tab, you can enter a date up to 10,000 years from the present in SkySafari Plus, and up to 500,000 years from the present in SkySafari Pro. You can also enter the time to the nearest second.

Julian Date is another method to set the date. Widely used in astronomy, the Julian Date is the number of days since January 1, 4713 B.C. The Julian Date begins at Greenwich noon, not midnight. Noon (i.e., 12h UTC) on 1 January 2000 A.D. is Julian Date 2451545.0. Julian dates do not observe any time zones or daylight saving time changes.

Local Sidereal Time is displayed near the bottom of the Date settings view. This indicates the hour of right ascension that is currently on your local meridian, and is sometimes used for aligning a telescope.