File:209_DidoModel.png · Wikimedia Commons · See Wikimedia Commons
Picture of the Day · NASA

Pathfinder on Mars
2026-07-04
On July 4th, 1997, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft bounced like a giant beach ball at least 15 times before it came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. After its then novel airbag-assisted landing sequence was completed, Pathfinder transmitted this color mosaic to mission operators on Earth. In the scene from another world, the Mars Sojourner robot rover is visible in the foreground, crouched on top of the unfolded Pathfinder. About the size of a large house cat, the six-wheeled, solar-powered Sojourner became the first successful Martian rover. Surrounding Pathfinder are deflated airbags and the rock-strewn terrain of the Ares Vallis floodplain. In the distance Martian hills appear against a dusty brownish sky. The Pathfinder lander was subsequently renamed the Carl Sagan Memorial Station.
via NASA APOD
Key facts
- Discovered by
- C. H. F. Peters
- Discovery date
- 22 October 1879
- Pronunciation
- / ˈ d aɪ d oʊ /
- Named after
- Dido
- Alternative designations
- A879 UC, 1909 AB, 1909 GB, 1912 RB
- Minor planet category
- Main belt
- Adjectives
- Didonian / d aɪ ˈ d oʊ n i ə n /
- Observation arc
- 136.47 yr (49,845 d)
- Aphelion
- 3.331 AU (498.3 Gm )
- Perihelion
- 2.968 AU (444.1 Gm)
- Semi major axis
- 3.150 AU (471.2 Gm)
- Orbital period sidereal
- 5.59 yr (2,040.5 d)
- Average orbital speed
- 16.79 km/s
- Mean anomaly
- 311.722°
- Mean motion
- 0° 10 34.738 / day
- Inclination
- 7.16997°
- Longitude of ascending node
- 0.682681°
- Argument of perihelion
- 248.387°
via Wikipedia infobox
Wikidata facts
- Instance of
- asteroid
- Named after
- Dido
- Followed by
- 210 Isabella
- Follows
- 208 Lacrimosa
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- 179.008
- Orbital period
- 2042.165856908191
- Image
- 000209-asteroid shape model (209) Dido.png
Show 19 more facts
- discoverer or inventor
- Christian Heinrich Friedrich Peters
- site of astronomical discovery
- Litchfield Observatory
- provisional designation
- A879 UC
- time of discovery or invention
- 1879-10-22
- asteroid spectral type
- X-type asteroid
- orbital inclination
- 7.165048850097697
- Commons category
- 209 Dido
- albedo
- 0.028
- rotation period
- 5.7366
- absolute magnitude
- 8.3
- orbital eccentricity
- 0.05328455831490172
- semi-major axis of an orbit
- 3.150129366651847
- periapsis
- 2.982276114715002
- apoapsis
- 3.317982618588692
- longitude of ascending node
- 0.5714483550555586
- argument of periapsis
- 250.1052471444713
- mean anomaly
- 190.2259450306205
- time of periapsis
- 2461963.5743845757
- epoch
- November 21, 2025
Sources (2)
via Wikidata · CC0
~2 min read
Encyclopedic overview
3D convex shape model of Dido
209 Dido is a main-belt asteroid with a diameter of 179±1 km. It was discovered by C. H. F. Peters on October 22, 1879, in Clinton, New York. The asteroid was named after the mythical Carthaginian queen Dido. This object is orbiting the Sun at a distance of 3.15 AU with an eccentricity (ovalness) of 0.058 and a period of 5.59 yr. The orbital plane is tilted at an angle of 7.2° to the plane of the ecliptic.
Excerpted from Wikipedia’s “209 Dido” article, available under the CC BY-SA 4.0 licence.