A small update resulting in Astro version 0.9.0 that adds Astro.lunar_phase_emoji/1 to return the phase of the moon as an emoji. For example:

iex> Astro.lunar_phase_emoji 0
"🌑"
iex> Astro.lunar_phase_emoji 45
"🌒"
iex> Astro.lunar_phase_emoji 90
"🌓"
iex> Astro.lunar_phase_emoji 135
"🌔"
iex> Astro.lunar_phase_emoji 180
"🌕"
iex> Astro.lunar_phase_emoji 245
"🌖"
iex> Astro.lunar_phase_emoji 270
"🌗"
iex> Astro.lunar_phase_emoji 320
"🌘"
iex> Astro.lunar_phase_emoji 360
"🌑"

iex> ~U[2021-08-22 12:01:02.170362Z]
...> |> Astro.lunar_phase_at()
...> |> Astro.lunar_phase_emoji()
"🌕"

I’ve released Astro 1.0 almost exactly a year after the last published version. This indicates API stability for existing functions (stable in most cases for at least 3 years). There is only one new function in this release:

Enhancements

• Release 1.0. This library was started four years ago and the public API has been stable for at least three of those years.

• Adds Astro.sun_azimuth_altitude/2. Thanks to @kimlai for the suggestion. Closes #3.

Astro version 0.6.0 is now out. This version avoids requiring some dependencies which makes the footprint smaller and compilation much faster. I have been using it to support the upcoming Chinese calendar with all tests passing so I consider the basic solar and lunar algorithms to be in solid shape.

Please note that Elixir 1.11 or later is required.

Roadmap

Roadmap to version 1.0 is to add Astro.moonrise/2 and Astro.moonset/2.

Additional development proposals or suggestions are very welcome.

Bug Fixes

• Fix Astro.Math.atan_r/2

• Fix Astro.Earth.ephemeris/1

Breaking changes

• Change Astro.Time.date_time_{from, to}_iso_days/1 to Astro.Time.date_time_{from, to}_moment/1

Enhancements

• Remove dependency on ex_cldr_calendar and jason

• Add Astro.sun_position_at/1 which is a public API for returning the right ascension, declination and radius (distance to the sun) at a given date/time.

• Add Astro.moon_position_at/1 which is a public API for returning the right ascension, declination and radius (distance to the moon) at a given date/time.

• Add Astro.illuminated_fraction_of_moon_at/1 to return the fraction of the moon that is lit at a given date/time.

Astro version 0.5.0 is now out. The release adds functions that calculate the phase of the moon which, apart from anything else, is needed to calculate the Chinese calendar. Please note that Elixir 1.11 or later is required.

Bug Fixes

• Updates documentation to be clear about installation and setup requirements for tz_world

• Fixes test data for São Paulo now that it no longer uses DST

• Ensure :astro is started in test mode

Enhancements

This primary focus of this release is to add lunar calculations for moon phase.

• Adds Astro.date_time_new_moon_before/1

• Adds Astro.date_time_new_moon_at_or_after/1

• Adds Astro.lunar_phase_at/1

• Adds Astro.date_time_lunar_phase_at_or_before/2

• Adds Astro.date_time_lunar_phase_at_or_after/2

New version 0.2.0 is now out:

Enhancements

• Add Astro.equinox/2and Astro.solstice/2 to calculate solstices and equinoxes for a year. From these can be derived the seasons.

• Add Astro.Time.datetime_from_julian_days/1

• Add Astro.Time.utc_datetime_from_terrestrial_datetime/1

Now on to lunar calculations (phase, moonrise, moonset)… And to implement the Persian calendar (which is a Solar based calendar).