Astronomy Fact
Due to its size, Pluto's moon Charon is considered to be a double dwarf planet (two planets orbiting each other), rather than a moon orbiting its planet.

Stellar Neighbors

Click on any star for more details. Hyperphysics

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Space Track-Satellite Passes

Notes about viewing ESVs:
When using lookangles, choose passes with high magnitudes; less than 6.0. ("Looks" are local time.)
Best viewing is when ESV is in Earth's penumbra; on the map, it's the solid line during night.
Dotted line on map denotes ESV is dark, in Earth's umbra (shadow).
Objects in orbit have to maintain a speed of at least 17,500mph, therefore ESVs traverse the sky noticeably different than aircraft.
ESVs appearing to blink are either tumbling rocket bodies, or spinning payloads with deployed solar arrays.
High-Eccentricity objects have a more ellongated orbit. Ground trace looks like a backwards C.
Regression-Ground traces will move West with each orbit due to Earth's rotation.

Script courtesy of: Lee from MadALwx. Page template and Facts script courtesy of: TNET Weather.
Page Template and Moon script courtesy of: Saratoga Weather. Graph base code courtesy of: jpGraph.