Update working-groups.md (#2191)

community/working-groups.md

@@ -15,7 +15,7 @@ UTC refers to [Coordinated Universal Time](https://en.wikipedia.org/wiki/Coordin
 
 | Working Group                    | Slack channel       | Meetings                                 | Contact                                                                  |
 | -------------------------------- | ------------------- | ---------------------------------------- | ------------------------------------------------------------------------ |
-| Astronomy                        | `#astro`            | Fourth Friday of each month at 19:00 UTC | [Mosè Giordano][Mosè-Giordano], [Miles Lucas][Miles-Lucas]               |
+| Astronomy                        | `#astro`            | Fourth Thursday of each month at 12:00 ET | [Paul Barrett][Paul-Barrett]                                            |
 | [Dagger][dagger]                 | `#distributed`      | Every other Thursday at 10am ET          | [Julian Samaroo][Julian-Samaroo], [Krystian Guliński][Krystian-Guliński] |
 | [Documentation tooling][wg-docs] | `#documentation`    | Last Tuesday of every month at 18:00 UTC | [Morten Piibeleht][Morten-Piibeleht], [Fredrik Ekre][Fredrik-Ekre]       |
 | [GPU][gpu]                       | `#gpu`              | Every other Monday at 11am ET            | [Tim Besard][Tim-Besard], [Valentin Churavy][Valentin-Churavy]           |