All posts by Justin Avery

Justin spends most of his time creating notebooks about space, and far too little time maintaining this site.

Pleiades to Hyades

This cosmic vista stretches almost 20 degrees from top to bottom, across the dusty constellation Taurus. It begins at the Pleiades and ends at the Hyades, two star clusters recognized since antiquity in Earth’s night sky. At top, the compact...

/ December 6, 2019

Spiral Galaxy NGC 6744

Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo and appears as only a faint, extended object in small telescopes. We...

/ December 5, 2019

Electric Night

It may appear, at first, like the Galaxy is producing the lightning, but really it’s the Earth. The featured nighttime landscape was taken from a southern tip of the Italian Island of Sardinia in early June. The foreground rocks and...

/ December 4, 2019

M27: The Dumbbell Nebula

Is this what will become of our Sun? Quite possibly. The first hint of our Sun’s future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets....

/ December 3, 2019

Mercury Crosses a Quiet Sun

What’s that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System’s innermost planet appeared to go just about straight across the middle. Although...

/ December 2, 2019

Starburst Galaxy M94 from Hubble

Why does this galaxy have a ring of bright blue stars? Beautiful island universe Messier 94 lies a mere 15 million light-years distant in the northern constellation of the Hunting Dogs (Canes Venatici). A popular target for Earth-based astronomers, the...

/ December 1, 2019

Star Trails for a Red Planet

Does Mars have a north star? In long exposures of Earth’s night sky, star trails make concentric arcs around the north celestial pole, the direction of our fair planet’s axis of rotation. Bright star Polaris is presently the Earth’s North...

/ November 30, 2019

Galileo s Europa Remastered

Looping through the Jovian system in the late 1990s, the Galileo spacecraft recorded stunning views of Europa and uncovered evidence that the moon’s icy surface likely hides a deep, global ocean. Galileo’s Europa image data has been remastered here, using...

/ November 29, 2019

Hoags Object: A Nearly Perfect Ring Galaxy

Is this one galaxy or two? This question came to light in 1950 when astronomer Arthur Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a...

/ November 27, 2019

Venus and Jupiter on the Horizon

What are those two bright objects on the horizon? Venus and Jupiter. The two brightest planets in the night sky passed very close together — angularly — just two days ago. In real space, they were just about as far...

/ November 26, 2019