Nature

Audubon Naturalist Society

Woodend Sanctuary, 8940 Jones Mill Road, Chevy Chase. 301/652-9188 or www.audubonnaturalist.org

• The largest and oldest independent environmental organization in the region.

National Aquarium in Baltimore

501 E. Pratt St., Baltimore, at the Inner Harbor. 10 a.m.-4 p.m. Monday-Thursday; 10 a.m.-8 p.m. Friday; 10 a.m.-5 p.m. Saturday, Sunday. Admission $12.95-$21.95, with a range of packages at $14.95-$28.95. 410/576-3800, 410-659-4278, www.aqua.org. Tickets through the Web site or ticketmaster.com, both with service charges.

• Hundreds of exhibits with more than 16,500 animals. Popular exhibits include “Animal Planet Australia: Wild Extremes,” “Frogs! A Chorus of Colors,” “Play! The Dolphin Show” and the new 4-D Immersion Theater. See the Web site for details.

National Aquarium in Washington, D.C.

U.S. Department of Commerce building, 1401 Constitution Ave. NW. 9 a.m.-5 p.m. daily; last admission 4:30 p.m. Closed Christmas and Thanksgiving. Admission $2.50-$5. 202/482-2825, www.nationalaquarium.com

• Animal keeper talks and animal feedings 2 p.m. daily: sharks Monday, Wednesday, Saturday; piranhas Tuesday, Thursday, Sunday; alligators Friday.

National Zoological Park

3001 Connecticut Ave. NW. Grounds open 6 a.m.-6 p.m. daily, buildings 10 a.m.-4:30 p.m. daily through March 31. Free. 202/633-4800, nationalzoo.si.edu

Planetarium: Arlington Schools

1426 N. Quincy St., Arlington. 703/228-6070.

• Public multimedia programs 7:30 p.m. Friday, Saturday; 1:30 and 3 p.m. Sunday during school year. “Stars Tonight” program, live interactive talk with the planetarium director and a dome full of stars, 7:30 p.m. first Monday of the month (second Monday when first Monday falls on a legal holiday) during school year. Doors open 15 minutes before the show. No reservations needed. $2, $3.

Planetarium: The Einstein Planetarium, National Air and Space Museum

Independence Avenue and Fourth Street SW. 10 a.m.-5:30 p.m. daily. Metro: L’Enfant Plaza. 202/633-1000, www.nasm.si.edu/visit/theaters/planetarium. Imax theater schedule: 877/932-4629.

• Planetarium shows: “Cosmic Collisions,” “Infinity Express,” $6.50-$8.50; call for showtimes. “The Stars Tonight — Open Your Eyes to the Skies,” 11:30 a.m. Tuesday, Thursday, Saturday. Free.

Planetarium: Rock Creek Park

Nature Center, 5200 Glover Road NW. 9 a.m.-5 p.m. Wednesday-Sunday. Closed major holidays. 202/895-6070 or www.nps.gov/archive/rocr/planetarium

• The only planetarium in the National Park system. Planetarium shows 1 p.m. Saturday, Sunday for children 4 and older; 4 p.m. Saturday, Sunday for children 7 and older. After-school show 4 p.m. Wednesday. Outdoor evening stargazing sessions once a month April-November at adjacent Military Field, off Military Road.

Second Chance Wildlife Center

7101 Barcellona Drive, Gaithersburg. 9 a.m.-5 p.m. daily. 301/926-9453, www.scwc.org

• The only rehabilitation facility for wildlife in the metro area. Orientation sessions for volunteers mid-February to mid-April.

U.S. Botanic Garden

100 Maryland Ave. SW, adjacent to the U.S. Capitol. Conservatory 10 a.m.-5 p.m. daily; National Garden 10 a.m.-5 p.m. through May 31. Free. 202/225-1116, www.usbg.gov

• “An Alphabet Garden of Orchids.” Annual show of hundreds of orchids, including rare and endangered species, from the collections of the U.S. Botanic Garden and the Smithsonian Institution’s Horticulture Services Division. Feb. 2-April 13.

• Exhibit tour: Orchid expert Michael Spelta leads a one-hour tour of the orchid exhibit. Conservatory Garden Court. 1-2 p.m. Feb. 8. Free. Registration required.

• “How Plants Work: A Guide to Being Green.” The daily realities of life as a plant. East Gallery. Permanent exhibit.

U.S. National Arboretum

3501 New York Ave. NE. 8 a.m.-5 p.m. daily. Closed Christmas and federal holidays. Free. 202/245-2726 or www.usna.usda.gov

• “Winter Landscapes.” National Bonsai & Penjing Museum. 10 a.m.-3 p.m. Through Feb. 3.

• Korean New Year Exhibition. Stones from Korea for the Lunar New Year and the artwork of Myung Sook Kim, a Korean-American painter, potter, and seal engraver. National Bonsai & Penjing Museum. 10 a.m.-3 p.m. Feb. 7-March 5.

• Full Moon Hikes. Arboretum grounds regardless of weather. 7-9 p.m. Feb. 19 and 20 (both full). $19. Registration required online or by mail; 202/245-4521 for information.