From Logan Airport: http://www.massport.com/logan/getti.html
Walking from the Harvard Square MBTA station:
The Harvard-Smithsonian Center for Astrophysics is about a half-mile and a 15-minute walk west of Harvard Square. Leave the Harvard Station by the Church Street exit, turn right on Massachusetts Ave., then left on Garden Street at the Cambridge Common. Bear right after the Sheraton-Commander Hotel, and the CfA is another two blocks on the left. From the Porter Station, walk back toward Harvard Square, turn right on Linnaean Street and keep walking straight on into the CfA's entrance driveway.
Bus or trolley from the Harvard Square MBTA station:
Take the 74 or 78 bus or 72 trackless trolley from the lower level of Harvard Station and ask to be let off at the "observatory steps" on Concord Avenue. Climb the steps to the rear parking lot. For more information, visit the MBTA website.
From the northwest:
Take Route 2 to the Alewife-Concord Rotary, follow Concord Avenue into Cambridge and cross Huron Avenue, turn left on Madison Street and then right into the CfA's rear parking lot.
From Boston or to the south:
Take Storrow or Memorial Drives to the Harvard Square exit (JFK Street), continue through the Square and up Mass. Ave. to turn left at Linnaean Street, which intersects Garden Street right at the front entrance driveway of the CfA.
From the north:
Take 93 South to Memorial Drive and follow directions from above.
From the west:
Take the Mass. Turnpike (US 90) to the Allston-Cambridge exit, cross the Charles River, and turn left on Memorial Drive immediately over the River Street Bridge. Then follow directions from above.