Emerald Timestamp lets you capture the precise times of events, and associate a description with each one. It's a universal app which runs at full resolution on the iPad, iPhone, and iPod touch.
Press the large button with the arrows pointing down to record the current time value. It will show up at the top of the list below. Add as many as you like; the list scrolls.
To add a one-line description, tap an event in the list and enter the description on the detail page (see below).
The iPhone's internal clock can be somewhat unreliable. So when Emerald Timestamp starts up (and every time it is awakened after the device has been locked) it uses NTP to synchronize its own clock with the international standard atomic clocks. This process requires network access and can take several seconds. Until it is done the accuracy of event timing is somewhat uncertain. During that uncertain time, Emerald Timestamp's big button is yellow. When the sync is complete, the button turns green and event timing is very accurate.
You can record events even when the button is yellow. If a sync is completed before the app is shut down or the device is locked, then the sync will be applied retroactively to all events captured since the last startup or unlock (and the displayed time values for such events may change as a result). The green/yellow indicator light to the left of each event indicates its time accuracy.
Tapping an event in the list brings up a page showing more detail about that event.
You can add a one-line description by tapping the "Event description" field.
You can email this event's details or the details of all the events.
The detail page also shows an accuracy bound for the time of the event. The accuracy of synchronized events is primarily constrained by the length of time it takes for a round trip from the device to the NTP server and back; server times are usually much more accurate than that round-trip time. Emerald Timestamp reports the accuracy based on that round-trip time, refined by a number of request-report cycles, presuming that each time it contacts a server the time reported is exact.
A synchronization is considered "green" if its reported accuracy is less than 0.2 seconds.
Tap the date or time at the top of either screen to change the format of the time displays. Each tap cycles between 12-hour local, 24-hour local, UTC (aka GMT), and Julian Date(an astronomical time reference).
Press the Edit button in the upper right to remove one or more events from the list.
Emerald Timestamp has two options that let you disable the device's Auto-Lock function so that it won't lock the screen while you're waiting for an event to occur. They are set with the Settings app.
Note: If you know that you are going to be in a location without network access when you want to record an event, you can try the following to possibly improve the accuracy of your event times:
