Time Interval Configuration
The time interval controls the granularity of the ephemeris by specifying how far apart each record is in time. A smaller interval produces more records with finer detail; a larger interval produces fewer records covering the same period.
Interval Fields
Two fields work together to define the interval:
- Interval -- A positive integer specifying the number of time units between records
- Time Unit -- The unit of time for the interval
Available Time Units
| Time Unit | Example Use |
|---|---|
| Seconds | Very fine-grained analysis (e.g., every 30 seconds) |
| Minutes | Detailed intraday analysis (e.g., every 15 minutes) |
| Hours | Hourly snapshots (e.g., every 6 hours) |
| Days | Daily ephemeris (e.g., every 1 day) |
| Months | Monthly overview (e.g., every 1 month) |
| Years | Long-term survey (e.g., every 1 year) |
Examples
- Every day for a year: Interval = 1, Time Unit = Days, date range spanning one year produces approximately 365 records
- Every hour for a week: Interval = 1, Time Unit = Hours, date range spanning one week produces approximately 168 records
- Every 15 minutes for a day: Interval = 15, Time Unit = Minutes, date range spanning one day produces 96 records
caution
Very small intervals over long date ranges can produce extremely large numbers of records. For example, an interval of 1 minute over a full year generates over 525,000 records. Consider your needs carefully before generating very large ephemerides.