September 3
Amber and Blue
Sun Position
The Sun is in Virgo near +7° declination. Northern Hemisphere evenings are warm and long but the equinox is close enough to feel; Southern Hemisphere observers are gaining about two minutes of daylight daily.
Sky Highlight
The Cygnus region transits the meridian high overhead for mid-northern-latitude observers around midnight this week, placing the entire Summer Triangle near zenith, ideal for dark-sky viewing of the Milky Way's richest nearby arm. Southern Hemisphere observers see Cygnus low in the northwest.
Deep Sky Object
NGC 6992, the Eastern Veil Nebula, Cygnus. A supernova remnant roughly 2,100 light-years away, this is a section of the Cygnus Loop, the expanding shell of a star that exploded perhaps 10,000 to 20,000 years ago. Best from the Northern Hemisphere with a nebula filter; very low and difficult from southern latitudes.
Featured Star
Albireo (β Cyg) is a celebrated double star about 430 light-years away, pairing an orange giant (spectral type K3II) with a blue main-sequence companion (B8Ve), the color contrast is vivid enough to be striking even in a small telescope. This is one of the sky's most instructive examples of how spectral type maps directly to color.
Around This Date
- September 3, 1976Viking 2's lander separated from its orbiter and began its descent toward Utopia Planitia, successfully touching down the same day and becoming the second spacecraft to operate on the Martian surface.
- September 5, 1977Voyager 1 launched from Cape Canaveral on a trajectory that would carry it past Jupiter and Saturn before it eventually became the first human-made object confirmed to have entered interstellar space.
Two stars, one amber and one blue, have shared the same line of sight for centuries, proof that color is not decoration but temperature made visible.