Deep Sky Observing

Articles about how to understand, find, and see celestial objects including stars, galaxies, nebulae, and star clusters with binoculars, telescopes, and the naked eye.

Touring the Summer Triangle

June 28, 2024 by Brian Ventrudo Filed Under: Deep Sky

Long-exposure images of the Summer Triangle (credit: Tien-Chu Chang, Flickr) — Long-exposure image of the Summer Triangle (credit: Tien-Chu Chang/Flickr)

While not a constellation itself, the Summer Triangle dominates the overhead sky in the northern summer and autumn months and guides stargazers to other stars, constellations, and deep-sky sights. The vertices of the triangle are marked by three bright stars Vega, Deneb, and Altair, each of which belong to true constellations Lyra, Cygnus, and Aquila, respectively. The image below shows the Summer Triangle rising as seen from mid-northern latitudes at 10 p.m. in mid July. The triangle is big: it spans about two full hand widths held at arm’s length. The triangle can be seen well south of the equator, too, above the northern horizon. Southern stargazers call it the “Northern Triangle” or the “Winter Triangle” [Read more…] about Touring the Summer Triangle

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The Eta Carinae Nebula

May 24, 2024 by Brian Ventrudo Filed Under: Astronomy Images and Video, Deep Sky

The Eta Carinae Nebula, the jewel of the southern-hemisphere constellation Carina, the Keel, is the most spectacular example of an active star factory in all the heavens. The nebula is about 260 light years across, some seven times larger than the Orion Nebula. And while 7,500 light years away, five times farther away than Orion, it’s still easily visible to the even the most casual stargazer as a large frosty patch three times as wide as the full Moon in the Milky Way west of the constellation Crux, the Southern Cross [Read more…] about The Eta Carinae Nebula

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Touring Queen Berenice’s Hair

April 11, 2024 by Brian Ventrudo Filed Under: Deep Sky

An historical representation of the constellations Bootes, Canes Venatici, and Coma Berenices (lower right).

Let’s take a look at the ancient constellation Coma Berenices, a faint group of stars tucked under the handle of the Dipper halfway between the stars Arcturus and Denebola in Leo’s hindquarters. There is something for everyone here: history and legend, a beautiful naked-eye star cluster that invites careful inspection, and dozens of galaxies to explore with a modest telescope. And armchair astronomers can contemplate the immensely distant Coma Cluster of Galaxies, some 300 million light years away, that first yielded evidence for the mysterious dark matter that makes up a good portion of the universe [Read more…] about Touring Queen Berenice’s Hair

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The Sound of the Jellyfish Nebula

March 26, 2024 by Brian Ventrudo Filed Under: Deep Sky, Science

A composite false-color image of the Jellyfish Nebula (IC443). Red indicates visible light, green shows regions of radio emission, and blue shows X-ray emission. Image credit: NASA/Chandra X-Ray Observatory.

Not far from the bright star Propus in the feet of the constellation Gemini lies the supernova remnant IC443, also known as Sharpless 248, but which is more evocatively known as the Jellyfish Nebula. While it’s a difficult object to see visually, this cosmic echo of a long-dead star presents a superb target for imagers because of its turbulent and complex structure. The nebula, which is about 5,000 light years away, is adjacent to a rich region of new star formation called Sharpless 249 in the Orion Spur of the Milky Way which makes the whole region even more photogenic.

The Jellyfish Nebula got its start when a massive star ran out of fuel, quickly collapsed, and detonated as a supernova about 30,000 years ago in a gas-strewn patch of the Milky Way. The shock wave from the explosion collided with clouds of interstellar gas and set them aglow to produced the intricate lacework of nebulosity that makes up the nebula. Most of the glowing gas is hydrogen, but there are also traces of light from ionized oxygen, sulfur, and other elements.
[Read more…] about The Sound of the Jellyfish Nebula

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The Flaming Star Nebula

February 27, 2024 by Brian Ventrudo Filed Under: Deep Sky

The Flaming Star Nebula (IC 405 or Caldwell 31) makes the must-see lists of many visual stargazers and astronomical imagers this time of year. This showpiece nebula in the northern constellation Auriga gains its energy from the star AE Aurigae, a 6^th-magnitude massive blue-white star about 1,500 light years away. This brilliant star, which outshines our Sun by some 30,000 times, blasts out ultraviolet light that ionizes the cloud of hydrogen gas around the star. As the hydrogen atoms reassemble, they emit light at visible wavelengths that make these nebulae so beautiful. IC 405 features a remarkably complex structure with knots of glowing gas that do indeed resemble starry flames frozen into the dark background sky.
[Read more…] about The Flaming Star Nebula

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