README
¶
Package sun implements solar time calculations.
The package provides a single function that returns the sunrise, sunset and solar noon for a given time and location.
Documentation
¶
Overview ¶
Package sun provides solar time calculations.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Times ¶
Times returns the times for sun rise, solar noon and sun set for the given time and location based on the formulae provided by the NOAA.
See https://gml.noaa.gov/grad/solcalc/solareqns.PDF
Example ¶
package main
import (
"fmt"
"log"
"time"
"github.com/kortschak/sun"
)
func main() {
// Calculate solar times for Paris on 2021-07-30.
loc, err := time.LoadLocation("CET")
if err != nil {
log.Fatal(err)
}
date := time.Date(2021, 7, 30, 12, 0, 0, 0, loc)
rise, noon, set := sun.Times(date, 48.856614, 2.3522219)
fmt.Printf("Sunrise: %v\nNoon: %v\nSunset: %v\n", rise, noon, set)
}
Output: Sunrise: 2021-07-30 06:20:05 +0200 CEST Noon: 2021-07-30 13:57:09 +0200 CEST Sunset: 2021-07-30 21:34:13 +0200 CEST
Types ¶
type Parser ¶
type Parser struct {
// CronParser is the parser used to handle
// any non-solar cron specs. If it is nil
// the standard github.com/robfig/cron/v3
// parser is used.
CronParser cron.ScheduleParser
}
Parser is a cron spec parser that handles solar event descriptors. These are
- @sunrise
- @noon
- @sunset
Each solar cron spec in in the form
@(sunrise|noon|sunset)([+-]duration)? lat lon
Example ¶
c := cron.New(cron.WithParser(sun.Parser{}))
// Set a reminder to go for a walk each evening.
_, err := c.AddFunc("@sunset-30m 48.856614 2.3522219", func() {
fmt.Println("Take a walk along the Seine before sunset.")
})
if err != nil {
log.Fatal(err)
}
c.Start()
select {}
Output:
type Schedule ¶
type Schedule struct {
// Event is the event type being scheduled.
Event Event
// Offset is the relative time offset relative
// to the solar-time event.
Offset time.Duration
// Lat and Lon are the latitude and longitude
// for the scheduled event.
Lat, Lon float64
// Location overrides the schedule location.
Location *time.Location
}
Schedule is a cron.Schedule that schedules solar-time events.
Source Files
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