Pasadena is served by Los Angeles International Airport (28 miles) and Burbank airport (16 miles). We suggest that you not rent a car (not particularly useful and not worth the money). Use taxis or equivalent. From LAX you can take "Flyaway" bus to Union station. Union Station is connected to Pasadena by ("Gold") light rail. The closest stop to Carnegie Observatories is Lake Avenue (two blocks). Useful if you are coming from UCSB, UCI or UCSD.