The Sidereal Time App gives the user a simple and quick way to determine:
- Local Apparent Sidereal Time (LAST) based on longitude
- Rough estimate of LAST based on Time Zone
- Greenwich Apparent Sidereal Time (GAST)
- Select one of 30 Stratum-1 NTP servers or add your own to synchronize the clock against the primary network time standard
The App uses core location (GPS, cellular triangulation and/or Skyhook Wireless's Wi-Fi system) to determine the users present position and hence his LAST. The user may also manually select the longitude coordinate to determine LAST or make a rough estimate by selecting a Time Zone.
A running clock with the Coordinated Universal Time is presented in parallel with the Sidereal Time clock.
Local Apparent Sidereal Time at any location differs from the Greenwich Sidereal Time value of the same moment, by an amount that depends on the longitude of the location. When one moves eastward 15° in longitude, sidereal time is larger by one hour and hence wraps around at 24 hours. Unlike computing local solar time, differences in longitude and time are counted here to the accuracy of measurement, not just in whole hours.
Updated for iOS 11.0.
Minor bug corrections.
Ratings and ReviewsSee All
Accurate calculation, but no night mode
Straight-forward app for displaying times useful for astronomers, such as UTC and LAST, and does so correctly to better than 1 second accuracy!
Unfortunately, this suffers from a major problem: I cannot find a setting to display as a night-vision safe dim red, making this useless as a visual astronomy observation clock.
Needs an alarm to alert when is your own sidereal time.
This seems to be a nice app. Simple, pleasing design, nice colors. But needs an alarm clock for sidereal time and a countdown clock without an alarm.
With Family Sharing set up, up to six family members can use this app.