Initial port to Go

.github/workflows/go.yaml

@@ -0,0 +1,25 @@
+name: Go
+on:
+  - push
+  - pull_request
+jobs:
+  build:
+    name: Test
+    runs-on: ubuntu-latest
+    # We want to run on external PRs, but not on our own internal PRs as they'll be run by the push to the branch.
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    steps:
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: '^1.15'
+        id: go
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v2
+      - name: Get dependencies
+        run: |
+          go get -v -t -d ./...
+      - name: Build
+        run: go build -v ./cmd/astral/
+      - name: Test
+        run: go test -race ./...

AUTHORS

@@ -5,3 +5,4 @@ Simon Kennedy
 Wojciech Pietruszeski
 Zachary Priddy
 Michael Marx
+Simon Jürgensmeyer

README.md

@@ -0,0 +1,75 @@
+# Astral
+
+![Action](https://github.com/sj14/astral/workflows/Go/badge.svg)
+[![GoDoc](https://godoc.org/github.com/sj14/astral?status.png)](https://godoc.org/github.com/sj14/astral)
+
+Calculations for the position of the sun and moon.
+
+This is a Go port of the Python [astral](https://github.com/sffjunkie/astral) package.
+
+The `astral` package provides the means to calculate the following times of the sun:
+
+* dawn
+* sunrise
+* noon
+* midnight
+* sunset
+* dusk
+* daylight
+* night
+* twilight
+* blue hour
+* golden hour
+* ~~rahukaalam~~ TODO
+
+plus solar azimuth and elevation at a specific latitude/longitude.
+It can also calculate the moon phase for a specific date.
+
+## CLI
+
+Besides the package for usage in you own programs, we also provide a tool for showing the data.
+
+### Installation
+
+```text
+go get github.com/sj14/astral/cmd/astral
+```
+
+### Usage
+
+```text
+Usage of astral:
+  -elev float
+        elevation of the observer
+  -format string
+        time output format according to Go parsing (default "Jan _2 15:04:05")
+  -lat float
+        latitude of the observer
+  -long float
+        longitude of the observer
+  -time string
+        day/time used for the calculation (defaults to current time)
+```
+
+### Example
+
+```text
+$ astral -lat 51.58 -long 6.52
+Sun Apr 18 11:12:45 CEST 2021
+Latitude 51.58 Longitude 6.52 Elevation 0
+Apr 18 05:55:07 Dawn
+Apr 18 05:55:07 Blue Hour Start
+Apr 18 06:09:04 Blue Hour End
+Apr 18 06:09:04 Golden Hour Start
+Apr 18 06:31:44 Sunrise
+Apr 18 07:15:56 Golden Hour End
+Apr 18 13:33:18 Noon
+Apr 18 19:51:24 Golden Hour Start
+Apr 18 20:35:45 Sunset
+Apr 18 20:58:33 Golden Hour End
+Apr 18 20:58:33 Blue Hour Start
+Apr 18 21:12:35 Blue Hour End
+Apr 18 21:12:35 Dusk
+Apr 19 01:33:13 Midnight
+Moon Phase: New Moon (5.47788888888889)
+```