Pokémon Sleep’s New Moon Day #17 event will run across all areas from Sept. 10 at 4 a.m. to Sept.13 at 3:59 a.m., with the new moon falling on Sept. 11. During the three-day event, Mythical Pokémon Mew and Darkrai will have special appearance rates regardless of sleep type, while Pokémon will be less likely to become full during the first snack time each day and Shiny Pokémon may also appear. Each encounter with a Pokémon benefiting from the special appearance rate during New Moon Day sleep research will also provide three additional friendship points, while failing to encounter one gradually increases the chance of finding one in later event sleep research. Special appearance Pokémon can only appear during the first sleep research of the day, and encountering one increases the number of Pokémon studied by one, allowing up to 11 encounters when using Pokémon Incense or a Good Camp Ticket. The New Moon Day Bundle Vol. 17 will also be available from Sept. 9 at 11 p.m. to Sept. 13 at 10:59 p.m. for 1,200 diamonds, containing one Ultra Biscuit, three Great Biscuits, 10 Poké Biscuits and three Friend Incenses, with a limit of one bundle per user.
Source: Official Pokémon Sleep news and PokemonSleep.net
Nintendo & Pokémon Blog 