A command line application that integrates with cron to execute tasks relative to sunset, sunrise and other such solar events.
Simply download a pre-compiled binary from the releases page.
Here's a quick compatibility table to help choose the correct binary to download:
| Platform | Binary | | -------- | ------ | | Raspberry Pi 0/1 | heliocron-v0.5.0-arm-unknown-linux-gnueabi.tar.gz | | Raspberry Pi 2/3/4 | heliocron-v0.5.0-armv7-unknown-linux-gnueabihf.tar.gz | | Linux with a 64bit CPU | heliocron-v0.5.0-x86_64-unknown-linux-gnu.tar.gz |
bash
$ cargo install heliocron
.
.
.
$ heliocron --version
heliocron 0.5.0
bash
$ git clone https://github.com/mfreeborn/heliocron
$ cd heliocron
$ cargo build --release
$ ./target/release/heliocron --version
heliocron 0.5.0
The following code snippet entered into the terminal will wait until sunset on 25th Feb 2020 at the Royal Greenwich Observatory (17:32:17 +00:00) before listing the files and folders contained within the user's home directory.
bash
$ heliocron --date 2020-02-25 --date-format %Y-%m-%d --latitude 51.4769N --longitude 0.0005W \
wait --event sunset && ls ~
Thread going to sleep for _ seconds until 2020-02-25 17:32:17 +00:00. Press ctrl+C to cancel.
Integration with Cron for recurring tasks is easy. The following snippet shows a Crontab entry which will run every morning at 2am. Heliocron will wait until 30 minutes before sunrise, before allowing the execution of the turn-on-lights.sh script.
bash
0 2 * * * heliocron --latitude 51.4769N --longitude 0.0005W wait --event sunrise --offset -00:30 \
&& turn-on-lights.sh
Ever wondered what time sunrise is in Edinburgh on 7th May 2065?
```bash $ heliocron -d "7 May 2065" -f "%e %B %Y" -l 55.9533N -o 3.1883W report
Latitude: 55.9533N Longitude: 3.1883W
2065-05-07 12:00:00 +01:00
Solar noon is at: 2065-05-07 13:09:19 +01:00 The day length is: 15h 49m 51s
Sunrise is at: 2065-05-07 05:14:24 +01:00 Sunset is at: 2065-05-07 21:04:15 +01:00
Civil dawn is at: 2065-05-07 04:27:31 +01:00 Civil dusk is at: 2065-05-07 21:51:08 +01:00
Nautical dawn is at: 2065-05-07 03:19:56 +01:00 Nautical dusk is at: 2065-05-07 22:58:43 +01:00
Astronomical dawn is at: Never Astronomical dusk is at: Never ```
Heliocron supports reading some configuration options from a file located at ~/.config/heliocron.toml. Note that this file is not created by default, it is up to the user to create the file correctly, otherwise Heliocron will simply pass over it. In particular, you can set a default latitude and longitude (must provide both, otherwise it will fall back to the default location of the Royal Greenwich Observatory).
```toml
latitude = "51.5014N" longitude = "0.1419W" ```
Now, using Heliocron without providing specific coordinates will yield the following output:
```bash $ heliocron -d 2020-03-08 report
Latitude: 51.5014N Longitude: 0.1419W
2020-03-08 12:00:00 +00:00
Solar noon is at: 2020-03-08 12:11:12 +00:00 The day length is: 11h 24m 22s
Sunrise is at: 2020-03-08 06:29:01 +00:00 Sunset is at: 2020-03-08 17:53:23 +00:00
Civil dawn is at: 2020-03-08 05:55:45 +00:00 Civil dusk is at: 2020-03-08 18:26:39 +00:00
Nautical dawn is at: 2020-03-08 05:17:04 +00:00 Nautical dusk is at: 2020-03-08 19:05:20 +00:00
Astronomical dawn is at: 2020-03-08 04:37:39 +00:00 Astronomical dusk is at: 2020-03-08 19:44:45 +00:00 ```
Observe that the location is set according to the contents of the configuration file.
Arguments passed in via the command line will override those set in the configuration file. Perhaps we want to check what is happening over at Windsor Castle without changing the configuration file:
```bash $ heliocron -d 2020-03-08 -l 51.4839N -o 0.6044W report
Latitude: 51.4839N Longitude: 0.6044W
2020-03-08 12:00:00 +00:00
Solar noon is at: 2020-03-08 12:13:03 +00:00 The day length is: 11h 24m 24s
Sunrise is at: 2020-03-08 06:30:51 +00:00 Sunset is at: 2020-03-08 17:55:15 +00:00
Civil dawn is at: 2020-03-08 05:57:36 +00:00 Civil dusk is at: 2020-03-08 18:28:30 +00:00
Nautical dawn is at: 2020-03-08 05:18:56 +00:00 Nautical dusk is at: 2020-03-08 19:07:10 +00:00
Astronomical dawn is at: 2020-03-08 04:39:32 +00:00 Astronomical dusk is at: 2020-03-08 19:46:34 +00:00 ```
Sometimes, a particular event will never happen on a certain day at a certain location. For example, the Sun never drops below 18° below the horizon in England during the height of summer; astronomical dawn and dusk never occur.
When using the report subcommand, this is identified like so:
bash
$ heliocron -d 2020-06-21 -l 52.8300N -o 0.5135E report
<-- snip -->
Astronomical dawn is at: Never
Astronomical dusk is at: Never
When using the wait subcommand, an error is raised and the program terminates immediately:
bash
$ heliocron -d 2020-06-21 -l 52.8300N -o 0.5135E wait -e astronomical_dusk
Runtime error: The chosen event does not occur on this day.
If you try and wait for an event which happened in the past, an error will be raised and the program will terminate immediately:
bash
$ heliocron -d 2020-06-21 -l 52.8300N -o 0.5135E wait -e sunrise
Runtime error: The chosen event occurred in the past; cannot wait a negative amount of time.
No such error arises if you just want a report from that date.
bash
heliocron [Options] <Subcommand> [Subcommand Options]
-d, --date [default: today]
Specify the date, by default in ISO 8601 format (YYYY-MM-DD).
-f, --format [default: %Y-%m-%d]
Specifiy the format of the date string passed to --date, using the syntax described here by the chrono crate.
-l, --latitude [default: 51.4769N]
Specify the north/south coordinate of the location. If --latitude is passed as a command line option, --longitude must also be provided.
Latitude must be a positive number between 0.0 and 90.0, suffixed with either "N" or "S" to determine north or south.
Can be specified in a file located at ~/.config/heliocron.toml (see Configuration), although note that options provided over the command line take precedence.
-o, --longitude [default: 0.0005W]
Specify the east/west coordinate of the location. If --longitude is passed as a command line option, --latitude must also be provided.
Longitude must be a positive number between 0.0 and 180.0, suffixed with either "E" or "W" to determine east or west.
Can be specified in a file located at ~/.config/heliocron.toml (see Configuration), although note that options provided over the command line take precedence.
-t, --time-zone [default: here and now]
Specify the time zone, in [+/-]HH:MM format, at which to calculate and display times.
Output the dates and times of sunrise, sunset, etc to stdout on the specified date at the specified location.
No further options are available.
Put the thread to sleep until the chosen event [+ offset] occurs on the specified date at the specified location.
-e, --event [required]Must be one of:
| Event | Description |
| ----- | ----------- |
| sunrise | The moment when the upper edge of the solar disk becomes visible above the horizon |
| sunset | The moment when the upper edge of the solar disk disappears below the horizon |
| civil_dawn | The moment when the geometric centre of the Sun reaches 6° below the horizon as it is rising |
| civil_dusk | The moment when the geometric centre of the Sun reaches 6° below the horizon as it is setting |
| nautical_dawn | The moment when the geometric centre of the Sun reaches 12° below the horizon as it is rising |
| nautical_dusk | The moment when the geometric centre of the Sun reaches 12° below the horizon as it is settting |
| astronomical_dawn | The moment when the geometric centre of the Sun reaches 18° below the horizon as it is rising |
| astronomical_dusk | The moment when the geometric centre of the Sun reaches 18° below the horizon as it is setting |
| custom_am | Allows the user to specify the moment when the geometric centre of the Sun reaches a custom number of degrees below the horizon as it is rising |
| custom_pm | Allows the user to specify the moment when the geometric centre of the Sun reaches a custom number of degrees below the horizon as it is setting |
-a, --altitude [required if --event is one of { custom_am | custom_pm }]Specify the number of degrees that the geometric centre of the Sun is below the horizon when using a custom_* event.
If this option is passed for any other event, it is simply ignored.
Example: ```bash
$ heliocron wait --event custom_pm --altitude 8.5 ```
-o, --offset [default: 00:00:00]Specify an offset, either in [-]HH:MM or [-]HH:MM:SS format, from the chosen event. Negative offsets (those which are prefixed with a '-' e.g. -01:00) will set the delay to be before the event, whilst positive offsets will shift the delay after the event.
--tag [optional]Allows specifying a custom string to describe or otherwise tag the process. When viewing all running processes, e.g. with htop, it will then be possible to filter against this tag as it appears on the command line.
This option has no other effect on the running of the program.