Astronomy Picture of the Day

A Sagittarius Triplet
Image Credit & Copyright: Josep Drudis

Explanation: These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula above and left of center, and colorful M20 near the bottom of the frame. The third emission region includes NGC 6559, right of M8 and separated from the larger nebula by a dark dust lane. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across the expansive M8 is also known as the Lagoon Nebula. M20’s popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. In striking contrast, blue hues in the Trifid are due to dust reflected starlight. The colorful composite skyscape was recorded with two different telescopes to capture a widefield image of the area and individual close-ups at higher resolution.

Tomorrow’s picture: noodling around

Astronomy Picture of the Day

The Milky Way over Monument Valley
Image Credit & Copyright: Tom Masterson

Explanation: You don’t have to be at Monument Valley to see the Milky Way arc across the sky like this — but it helps. Only at Monument Valley USA would you see a picturesque foreground that includes these iconic rock peaks called buttes. Buttes are composed of hard rock left behind after water has eroded away the surrounding soft rock. In the featured image taken in 2012, the closest butte on the left and the butte to its right are known as the Mittens, while Merrick Butte can be seen farther to the right. Green airglow fans up from the horizon. High overhead stretches a band of diffuse light that is the central disk of our spiral Milky Way Galaxy. The band of the Milky Way can be spotted by almost anyone on almost any clear night when far enough from a city and surrounding bright lights, but a sensitive digital camera is needed to capture these colors in a dark night sky.

Tomorrow’s picture: sagittarius triplet

Astronomy Picture of the Day

Int-Ball Drone Activated on the Space Station
Image Credit: JAXA, ISS, NASA

Explanation: What if you were followed around by a cute floating ball that kept taking your picture? Then you might be an astronaut on today’s International Space Station (ISS). Designed by the Japan Aerospace Exploration Agency (JAXA), the JEM Internal Ball Camera — informally “Int-Ball” — is a bit larger than a softball, can float and maneuver by itself but also be controlled remotely, can take high resolution images and videos, and is not related to Hello Kitty. Int-Ball was delivered to the ISS in early June and is designed to allow ground-control to increase the monitoring of ISS equipment and activities while decreasing time demands on human astronauts. Int-Ball moves by turning on small internal fans and sees with a camera located between its two dark eyes.

Tomorrow’s picture: milky way towers

Astronomy Picture of the Day

A Hybrid Solar Eclipse over Kenya
Image Credit & Copyright: Eugen Kamenew (Kamenew Photography)

Explanation: Chasing solar eclipses can cause you to go to the most interesting places and meet the most interesting people. Almost. For example, chasing this eclipse brought this astrophotographer to Kenya in 2013. His contact, a member of the Maasai people, was to pick him up at the airport, show him part of southern Kenya, and even agreed to pose in traditional warrior garb on a hill as the hopefully spectacular eclipse set far in background. Unfortunately, this contact person died unexpectedly a week before the astrophotographer’s arrival, and so he never got to participate in the shoot, nor know that the resulting image went on to win an international award for astrophotography. Pictured in 2013 from Kenya, the Moon covers much of the Sun during a hybrid eclipse, a rare type of solar eclipse that appears as total from some Earth locations, but annular in others. During the annular part of the eclipse, the Moon was too far from the Earth to block the entire Sun. Next month a total solar eclipse will cross the USA.

Tomorrow’s picture: astronaut’s floating friend

Astronomy Picture of the Day

Mercury as Revealed by MESSENGER

Explanation: Mercury had never been seen like this before. In 2008, the robotic MESSENGER spacecraft buzzed past Mercury for the second time and imaged terrain mapped previously only by comparatively crude radar. The featured image was recorded as MESSENGER looked back 90 minutes after passing, from an altitude of about 27,000 kilometers. Visible in the image, among many other newly imaged features, are unusually long rays that appear to run like meridians of longitude out from a young crater near the northern limb. MESSENGER entered orbit around Mercury in 2011 and finished its primary mission in 2012, but took detailed measurements until 2015, at which time it ran out of fuel and so was instructed to impact Mercury’s surface.

Tomorrow’s picture: hybrid eclipse

Astronomy Picture of the Day

Apollo 11: Catching Some Sun
Image Credit: Apollo 11, NASA (Image scanned by Kipp Teague)

Explanation: Bright sunlight glints and long dark shadows mark this image of the lunar surface. It was taken July 20, 1969 by Apollo 11 astronaut Neil Armstrong, the first to walk on the Moon. Pictured is the mission’s lunar module, the Eagle, and spacesuited lunar module pilot Buzz Aldrin unfurling a long sheet of foil also known as the Solar Wind Composition Experiment. Exposed facing the Sun, the foil trapped particles streaming outward in the solar wind, catching a sample of material from the Sun itself. Along with moon rocks and lunar soil samples, the solar wind collector was returned for analysis in earthbound laboratories.

Tomorrow’s picture: mercury mellon

Astronomy Picture of the Day

Phobos: Moon over Mars
Image Credit: NASA, ESA, Zolt Levay (STScI) – Acknowledgment: J.Bell (ASU) and M.Wolff (SSI)

Explanation: A tiny moon with a scary name, Phobos emerges from behind the Red Planet in this timelapse sequence from the Earth-orbiting Hubble Space Telescope. Over 22 minutes the 13 separate exposures were captured near the 2016 closest approach of Mars to planet Earth. Martians have to look to the west to watch Phobos rise, though. The small moon is closer to its parent planet than any other moon in the Solar System, about 3,700 miles (6,000 kilometers) above the Martian surface. It completes one orbit in just 7 hours and 39 minutes. That’s faster than a Mars rotation, which corresponds to about 24 hours and 40 minutes. So on Mars, Phobos can be seen to rise above the western horizon 3 times a day. Still, Phobos is doomed.

Tomorrow’s picture: to catch some sun