P-M Heden of The World at Night took this photo from Uppsala, Sweden in Sept. 2012. This deep landscape shot required only a wide aperture and filter to boost contrast.Image: P-M Heden / Clearskies.se / The World at Night

One of the pleasures people can get out of stargazing is noticing and enjoying the various colors that stars display in dark skies.

These hues offer direct visual evidence of how stellar temperatures vary. A good many of the summer luminaries — such as brilliant Vega which this week stands nearly overhead at around midnight — are bluish-white, but we can easily find other, contrasting colors there as well.

Look at reddish Antares, which is due south at around 10 p.m. EDT, and the yellowish-white Altair, which stands high in the south at 1 a.m. EDT. Considerably removed from this summer retinue, brilliant yellow-orange Arcturus holds forth in solitary splendor about halfway up in the west-southwest as darkness falls on these balmy July evenings.

Double color

Probably the most colorful double star in the night sky can now be found about two-thirds of the way up from the eastern horizon to the point directly overhead at 10 p.m. local daylight time: Albireo in the constellation of Cygnus, the swan, also known as the Northern Cross. Albireo supposedly marks the swan’s beak, or the base of the cross.

A small telescope or even a pair of steadily held binoculars will readily split Albireo into two tiny points of light of beautiful contrasting colors: the brighter one a rich yellowish-orange, the other a deep azure blue, both placed very close together.

Astronomer Garrett P. Serviss referred to Albireo as “… unrivaled for beauty, the larger star being pale topaz and the smaller a deep sapphire.”

via Starry Night: Colors of Summer Stars Explained: Scientific American.

Way To Go Dave Keep Up The Good Work!!

PASADENA, Calif. — Color and black-and-white images of Earth taken by two NASA interplanetary spacecraft on July 19 show our planet and its moon as bright beacons from millions of miles away in space.

NASA’s Cassini spacecraft captured the color images of Earth and the moon from its perch in the Saturn system nearly 900 million miles (1.5 billion kilometers) away. MESSENGER, the first probe to orbit Mercury, took a black-and-white image from a distance of 61 million miles (98 million kilometers) as part of a campaign to search for natural satellites of the planet.

In the Cassini images Earth and the moon appear as mere dots — Earth a pale blue and the moon a stark white, visible between Saturn’s rings. It was the first time Cassini’s highest-resolution camera captured Earth and its moon as two distinct objects.

It also marked the first time people on Earth had advance notice their planet’s portrait was being taken from interplanetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet. More than 20,000 people around the world participated.

“We can’t see individual continents or people in this portrait of Earth, but this pale blue dot is a succinct summary of who we were on July 19,” said Linda Spilker, Cassini project scientist, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Cassini’s picture reminds us how tiny our home planet is in the vastness of space, and also testifies to the ingenuity of the citizens of this tiny planet to send a robotic spacecraft so far away from home to study Saturn and take a look-back photo of Earth.”

via NASA Releases Images of Earth Taken by Distant Spacecraft | NASA.