The "world's largest annual global celebration of astronomy" is organized each April by Astronomers Without Borders, according to a press release. Astronomers Without Borders describes itself as "a leader in promoting understanding and peaceful international relations, while also supporting outreach and education in astronomy."

The following list of programs and event dates are taken from the press release provided by Astronomers Without Borders:

Dozens of programs fill the month of April, with highlighted events worldwide, including these:

 * Stars For All! In what may be a world first, astronomical images created in real time will be downloaded and converted into tactile surfaces, allowing people with visual impairments around the world to experience the wonder of observing LIVE with the Virtual Telescope.

 * OPTICKS, a Cosmic Mail Art, transmits images to the Moon and back as radio signals in real time. This special event will see Apollo 16 astronaut Charlie Duke's family photo (a print of which was left behind when Duke left the Moon) and Apollo 12 astronaut Alan Bean's lunar paintings both making the round-trip to the Moon and back -- at least on radio waves.

 * Thousands will view the heavens through telescopes provided by amateur astronomers and science centers during the Global Star Party, SunDay, and other observing events.

 * The Moon takes center stage with a total lunar eclipse and other special programs.

 * Online observing with popular astronomer Gianluca Masi will feature live interaction with a worldwide audience in four special GAM events: a Lunar Eclipse, the hugely popular Online Messier Marathon, Stars for All, and Walking on the Moon.

 * AWB's wide-ranging AstroArts program connects art and culture with astronomy in exciting ways with blog posts and special live webcasts, including the annual Cosmic Concert with original music composed and performed by Giovanni Renzo.

 * Partner programs bring new audiences and participants: Measuring light pollution worldwide in Globe at Night, classrooms discovering asteroids in the International Asteroid Search Campaign, and more.

 * And there's an app for GAM! Alive Video Wallpaper for Android mobile devices from Bonne-App has a stunning line-up of GAM 2015 wallpapers anyone can download. Not only do they make a great souvenir of this years premier astronomical celebration but a portion of proceeds go to supporting AWB's worldwide outreach programs.

The GAM 2015 website (https://www.gam-awb.org) is the hub of all activities, with galleries, articles, and fresh content continuously posted. GAM participants will be adding their reports and photos about their local GAM events and program from all parts of the world.

Here is the schedule of our GAM happenings scheduled to date:

 March 1 - April 30 AstroPoetry Contest
March 21 - April 25 IASC Asteroid Search Campaign
March 22 - April 22 International Earth and Sky Photo Contest April 1 - April 30 Discovering the solar system (Observing Challenge)
April 1 - April 30 Lunar Explorations (Observing Challenge)
April 1 - April 30 The Undiscovered Universe (Observing Challenge)
April 2 Shadows around Jupiter: Callisto eclipses Ganymede (Online Observing Event)
April 4 Lunar Eclipse
April 4 Lunar Eclipse (Online Observing Event)
April 9-18 Globe at Night
April 11 Online Messier Marathon (Online Observing Event)
April 12 SunDay
April 13-18 International Dark Skies Week
April 16 Stars for All (Online Observing Event)
April 21 Myths on the Birth of the universe (Hangout)
April 21 The Moon plows through the Hyades (Observing Challenge)
April 24 Walking on the Moon (Online Observing Event)
April 25 Global Star Party
April 25-26 CosmoQuest Hangoutathon
April 26 AStroconcert 'Icy Rose 67P'
April 28 Cosmic Concert
April 30 OPTICKS

Go to https://astronomerswithoutborders.org/ for more information on available online events.