Join @smithsoniannmai, @nmaahc, Hirshhorn, @natasianart, Smithsonian National Museum of African Art , @nmnh, Smithsonian Gardens, National Air and Space Museum, and National Museum of American History all day AND late into the night on Saturday for sunny, free activities, including a Glow Night Arcade Party at our Arts & Industries Building.

Big, small, or covered in pond scum, @Smithsonian photographers have always tested the limits of their equipment to get that perfect shot. Smithsonian Archives has great examples for #NationalCameraDay, like photographers Thomas Smillie & Kjell Sandved hard at work behind the lens.

🤖 The pout on this Baker-Nunn camera wishes you a joyous #NationalCameraDay. In the 1950s and 1960s, SmithsonianObs (SAO) ran 12 tracking stations worldwide to monitor natural and artificial satellite activity. Each one had a Baker-Nunn camera. This frowner was based in Australia. 🇦🇺

So long and thanks for all the fish. It's the last day of #WorldOceansMonth! This Smithsonian Archives photo was taken by Carl Hansen in 1989 at Smithsonian Panama, where we've been doing groundbreaking research on tropical ecosystems for decades.🌊

☠️Our Smithsonian Archives conservator Nora Lockshin weighs in on a poison-laced ledger book with Sidedoor Podcast :

Meet three @nmnh scientists who fought for suffrage➡️ 🎨✍️Violet Dandridge, scientific illustrator: s.si.edu/3a2IBAi 🌿🪧Mary Agnes Chase, expert in grasses: s.si.edu/46IeHOG 🩺🦟Evelyn G. Mitchell, entomologist & physician: s.si.edu/2xYzQsh #SenecaFalls175

Groundbreaking climate scientist Eunice Newton Foote was a collaborator of first Smithsonian Secretary Joseph Henry. ➡️s.si.edu/eunice-foote We wish we had a photo of her, but we'll settle for the Doodle.👩‍🔬

54 years ago today, the #Apollo11 mission gave us some of the solar system’s most famous photos. But they missed something major: crew member and future National Air and Space Museum director Michael Collins’ expert-level mugging for the camera. 📸🧑‍🚀🙃🙂 Not to worry: we've got the pics.

Moth-ing to see here, people—just some weird liquid, buckets, and a tropical biologist. In 1987, Smithsonian Panama photographers captured these shots of Neal Griffith Smith at work on a study of Urania moths. More on Neal's research ➡️ s.si.edu/neal-griffith-… #MothWeek 🦋

Wandering through wildflowers with Mary Vaux Walcott. Born #OTD in 1860, Walcott was a naturalist and artist. But her work was sometimes confused for her husband's, @Smithsonian Secretary Charles Walcott. Learn how we're using data science to uncover it: s.si.edu/3rGW7qr

Happy 177th birthday to us! 🎂🥳 #OTD in 1846, the U.S. Senate passed the "Act to Establish the 'Smithsonian Institution,' for the Increase and Diffusion of Knowledge among Men.” And yet, we don’t look a day over 131. 📸: 77-10604-12

Light. ☑️ Subject. ☑️Composition. ☑️ An unorthodox posture. ☑️☑️ On #NationalPhotographyDay, we celebrate the Smithsonian photographers who are willing to do anything for the shot. 📸: MAH-4460, MAH-4690, 96-927

In 1963, Dr. Martin Luther King Jr. helped organize the March on Washington for Jobs and Freedom. There, he would give his iconic "I Have a Dream" speech. Jim Wallace captured this photo of the crowd that day. From Smithsonian Archives collections: s.si.edu/3qtQbOs