Over a century ago, Henrietta Swan Leavitt revolutionized astronomy by discovering a powerful link between a star’s brightness and its pulsation period. Her groundbreaking work became the key to measuring vast cosmic distances and ultimately led to the discovery of the universe’s expansion. Now, with modern data, scientists have revisited her research—what new insights have they uncovered? How does her work continue to shape our understanding of the cosmos today?

Join us for an evening of discovery as ESA Research Fellow Louise Breuval (Space Telescope Science Institute) and NSF fellow Caroline Huang (CfA), present and explore Leavitt’s lasting impact, the latest findings, and how we still use her insights to map the universe. Then, step onto the roof of the Center for Astrophysics | Harvard & Smithsonian for telescope observations, where we’ll observe the cosmos just as Henrietta once did—weather permitting.

This event is sponsored by the Harvard College Observatory (HCO), part of the Center for Astrophysics | Harvard & Smithsonian (CfA). The CfA sponsors a variety of free programs for the public. Among these events are Public Observatory Nights. Observatory Nights feature two 20-minute non-technical lectures, and telescopic observing from the observatory roof if weather permits. The lectures are intended for high-school age and older audiences, but all are welcome. Admission is free, however, tickets are limited, and seating is first-come, first-served. Max 4 tickets per email address.

These events are held in Phillips Auditorium (at the rear of the CfA complex near Madison Street and the large parking lot), 60 Garden Street, Cambridge, about 1 mile west of Harvard Square. Parking lots marked for Observatory Staff are open to the public on event nights. Parking is FREE.

A few important points to keep in mind:

- This is a ticketed event, and all attendees must have a ticket for admission. Cancelled tickets will be readministered to individuals on the waitlist.

- Observations on the roof are weather-dependent. In case of unfavorable weather conditions, the talks will proceed as scheduled, but outdoor observations will be canceled. A tour of our historic Great Refractor will be offered if telescope observations are cancelled.

- Access to the roof is via stairs only. If you or a member of your party have any mobility limitations, please get in touch.

- Ensure you dress warmly for the occasion.

- High heels are not permitted on the roof.

- Some photography will take place. We generally avoid photographing faces, and focus more on the guest speakers and nighttime telescope activities. If you have any issues with photography, please reach out and let us know.

We look forward to your presence at the event! Please check the HCO outreach website for more details on our public engagement programs: https://hco.cfa.harvard.edu/ou...