The Blue Hills Observatory and Science Center has reopened for tours, with masks required:  Weekends (Fridays through Mondays) 10AM-4PM and every other day by appointment 8:30AM-5:30PM. Each tour has a maximum of 4 people or one household of up to 7 people. Make reservations by phone 617-696-0562 or email to dmccasland@bluehill.org. Rooftop tour: $4 ($2 youth). Roof and History Room: $5 ($3 youth). In-depth tour: $8 ($5 youth). Discounts are available for students and members of some organizations. Also check BHOSC’s schedule of free online webinars and consider subscribing to its newsletter.