Visual Satellite Observer's Home Page

[Soyuz Image] [Satellite Trail Image] [Shuttle ET Image]
From left to right the above images are: A Soyuz manned capsule. Satellite captured on a long exposure photograph. The external tank caught just after separation during the STS-2 shuttle mission.

If you have ever star-gazed shortly after sunset or before sunrise, you have probably noticed one or two "stars" sailing gracefully across the sky. These are Earth-orbiting satellites, visible due to the reflection of the Sun's light off their surfaces toward the observer. Hundreds of satellites are visible to the unaided eye; thousands are visible using binoculars and telescopes. Observing satellites has many enthusiasts around the world.

Amateur astronomers seeking new challenges, find that spotting faint, rapidly moving satellites, such as the tiny Vanguard 1 (America's second satellite), are comparable to spotting a distant galaxy. Tracking down a newly launched spy satellite in a secret orbit, tests analytical as well as observational skill. Observing the International Space Station transit the sun, moon or one of the planets, requires planning, perseverance, and often a bit of luck.

Positional observers precisely measure the time and position of satellites as they cross the sky. During the first 30 years of the space age, geophysicists used such hobbyist measurements alongside those of radars and telescopic cameras, to analyze small changes in satellite orbits - called perturbations - to reveal details of Earth's upper atmosphere and gravity field. Today, positional observers contribute to public knowledge by finding, tracking and publishing the orbits of satellites in secret orbits.

Flash observers, measure the period of rotation of spinning satellites, leading to a better understanding of the near Earth environment, especially its magnetic field.

Space enthusiasts find that satellite observation leads naturally into such diverse fields as orbital mechanics, computer programming, rocket propulsion, mathematics, physics, applications of satellites, and government space policy.

This web site provides information on all facets of visual satellite observation: