2-Day Trip Planned to Channel Islands

Sierra Club natural science section naturalists will lead an overnight trip to Santa Barbara Island in the Channel Islands National Park April 11 and 12.

Participants will travel by boat to the one-square-mile island to observe the sea lion rookery there, learn about island plant and animal communities and perhaps spot migratory whales.

Space is limited for this trip and early reservations are required. Call (818) 445-6778.

BOTANY

The Palm Springs Desert Museum Natural Science Council will sponsor a symposium on desert cacti featuring experts from around the country on Saturday from 10 a.m. to 3:30 p.m. The symposium is in conjunction with the recently opened desert cacti exhibit at the museum. Call (619) 325-7186.

ASTRONOMY

As a result of incorrect information provided to The Times, the date of the Western Observatorium trip mentioned in last week’s calendar was incorrect. “Star Treks in the Santa Monicas” will take place on Saturday at 8:30 p.m. at Rocky Oaks Park. Call (818) 707-8540.

Randii Wessen of the Jet Propulsion Laboratory’s planned Cassini mission to Saturn and Titan will discuss robotic space exploration in “Planetary Exploration in the 1990s,” the Santa Monica College Planetarium program on Friday at 8 p.m., immediately following the weekly night sky show at 7. Call (310) 452-9223.

Lecturers Dennis Leatart and Hal Jandorf will demonstrate “Simple Astrophotography” at the Moorpark College astronomy show Saturday at 7:30 p.m. in the Charles Temple Observatory on campus. Call (805) 378-1408.

MARINE SCIENCE

Cabrillo Marine Museum staffers will help participants identify sea anemones, crabs and other tide pool animals in the popular weekend tide pool walks at the Point Fermin Marine Life Refuge on Sunday at 11:30 a.m. Dates in April, May and June are also scheduled. Call (310) 548-7563.