The Time button in the main Sky Chart toolbar displays a set controls which let you flow the date and time dynamically, or adjust it step-by-step. Tap the Time button to show these controls; tap it again to hide them.
When visible, the time flow controls contain the following items:
Current Time Label: The chart's current date and time is shown at the top of the panel. If there is an underlined segment, this indicates the time unit that will be used for flowing or stepping time (e.g. by days, hours, minutes, etc).
Time Flow Arrows: In the middle of the panel is a set of VCR controls lets you start and stop the flow of time. Tap the rightmost arrow to start the flow of time continuously forward; tap the leftmost arrow to flow time continuously backward. Tap either of these arrows to stop the flow of time.
Time Step Arrows: The central arrows adjust the time by a single step, equal to the time unit you have selected underneath. For example, if you selected 1 day as the time unit, tapping the center right arrow will move the time forward by 1 day - but it will not continuously run the time by one day.
Now Button: Stops the flow of time, and returns to the current date and time indicated by your device's internal clock.
Time Units Button: The button in the lower left shows the time unit you will change time by when stepping or flowing time. Tapping the button brings up a panel where you can change the time unit. The unit can also be quickly changed by tapping the corresponding part of the time label at the top of the panel. For example you would tap the day part of the time and date to change the unit to days.
In SkySafari Plus and Pro, the number in the time unit button is a multiplier applied to the time unit. You can tap the button to enter a new multiplier with the numeric keypad - for example: 10 minutes, 7 days, 86164 seconds (one sidereal day), or 24.659784 hours (one Martian day). Please Note: in the basic version of SkySafari, you can only use time steps of exactly one minute, one day, etc.
You'll find that different astronomical phenomena are best simulated using different time units. For example:
Second - best for showing the motion of fast-moving satellites.
Minute - best at showing the daily rise-and-set motion of the Sun, Moon, and Stars.
Hour - best for showing the motion of Jupiter and Saturn's moons.
Day - best for showing the motion of the planets against the background stars, as they (and we!) orbit the Sun.
Year - best for showing the orbital motion of binary star systems like Sirius and Alpha Centauri.
Time flow is temporarily paused when another view (like Search, Object Info, or Settings) is present. You can also use the Settings to change the simulated date and time. If you are using SkySafari to control a telescope, we do not recommend using Time Flow while the telescope is connected - simulating a view other than the current date and time may result in pointing the telescope at the wrong place in the sky!