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.

The Star of Good Fortune, and Old Age

February 14, 2019 by Brian Ventrudo Filed Under: Deep Sky

The star Canopus, low in the sky and left of center in this image, lies well below the constellation Orion, at top center, and Canis Major (at upper left). As seen from the Winter Star Party, near Summerland Key, Florida, in 2017.

Canopus is located in the southern constellation Carina, the Keel, and it is by far the brightest star in the constellation. At a declination of about -52^o, Canopus never rises above the horizon for observers north of 38^oN latitude. Many northerners catch sight of it while travelling south for winter vacation. Almost directly south of Sirius, Canopus is just visible in the months of northern winter from southern Spain and Portugal, and from the southern United States. In the southern hemisphere, these two brightest stars are directly overhead in the evening summer sky [Read more…] about The Star of Good Fortune, and Old Age

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The Hyades Star Cluster

February 7, 2019 by Brian Ventrudo Filed Under: Deep Sky

The Hyades, below and left of center, and the Pleiades, two open star clusters in the northern zodiacal constellation Taurus. Image credit: Brian Ventrudo. Click to enlarge.

It’s the second-closest star cluster to Earth, and it appears so large that many new stargazers don’t even know it’s a true star cluster. But the Hyades, which make up the V-shaped head of the constellation Taurus, the Bull, is a resplendent collection of young, mostly blue-white stars that are lovely to the unaided eye and a wonder to behold in a pair of binoculars.

Often overshadowed by the smaller and more famous and apparently smaller Pleiades to the west, the Hyades are visible high in the northern sky this time of year. They’re visible from the southern hemisphere, too, perhaps 20° above the northern horizon just after sunset in South Africa, Australia, and New Zealand. An easy way to spot the Hyades? Follow a line from Orion’s Belt to the northwest until you see the little V with the bright orange star Aldebaran at one apex and keep going to get to the Pleiades. Follow Orion’s Belt in the other direction and you’ll find the bright blue-white star Sirius, the brightest star in the sky. The image below shows you what to look for [Read more…] about The Hyades Star Cluster

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A Quintuple Star in the Constellation Orion

January 25, 2019 by Brian Ventrudo Filed Under: Deep Sky

The complex of emission, reflection, and dark nebulae near the star Alnitak and Sigma Orionis. The Horsehead Nebula is at center. Sigma Orionis is the bright star to the left of the Horsehead. The pale white Flame Nebula, split in two by a dark lane of dust, is at bottom and just right of center. Image credit: Terry Hancock and GrandMesaObservatory.com

Perhaps the finest multiple star in the sky visible to both northern and southern observers, Sigma Orionis is a gravitationally-bound system of five stars, four of which are visible upon careful inspection with a small telescope. The brightest star of this group is one of the most luminous known, and it lights up the gas and dust around the famous Horsehead Nebula near Orion’s Belt. The star will one day expire, like many stars in Orion, in a spectacular supernova explosion.

Sigma Orionis doesn’t have an easy-to-remember name, but it’s not hard to find. It’s just south of Alnitak, the easternmost star in Orion’s Belt. The total visual magnitude is 3.6, so it’s visible even in light-polluted city skies [Read more…] about A Quintuple Star in the Constellation Orion

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The ‘Seven (Dusty) Sisters’

January 18, 2019 by Brian Ventrudo Filed Under: Deep Sky

An image of the Pleiades Star Cluster (Messier 45) and surrounding region. Image courtesy of Terry Hancock and Grand Mesa Observatory.

Like many observers both casual and serious, I do not tire of gazing upon the little star cluster known as the Pleiades. I’ve seen the cluster a thousand times, but I’ll still stop and take a long look at it without optics while out for a walk on a winter’s night. Some night I’ll grab a pair of binoculars and make a closer inspection of the cluster, which fits perfectly in the field of view of such an instrument. And if it’s not too cold, I’ll pull out a telescope and a wide-field eyepiece and spend 20 minutes taking in the astonishing view of this group of blue-white stars that formed while dinosaurs still roamed the Earth. Which, in celestial terms, was not all that long ago.

Why keep looking at the Pleiades after so many years? The cluster doesn’t appear to change, of course, in the restricted timescale of a human life. But the Pleiades is a profoundly beautiful sight, as pleasing as a field of alpine wildflowers, and I never fail to see new patterns of stars both bright and dim that I hadn’t noticed before [Read more…] about The ‘Seven (Dusty) Sisters’

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The Lonely Star of Autumn

December 7, 2018 by Brian Ventrudo Filed Under: Deep Sky

This illustration shows a ring of debris encircling the star Fomalhaut. A suspected planet is orbiting inside the ring. Credit: NASA, ESA and A. Feild (STScI)

In the vast expanse of sky between the brilliant stars Antares in the west and Sirius in the east, there lies but a single bright star of note, the star Fomalhaut. Low and prominent over the southern horizon, this lovely white star is a lonely sight on a northern fall evening. Fomalhaut marks the mouth of the constellation Piscis Austrinus (the Southern Fish). The star is a pretty enough sight for casual stargazers this time of year, and it offers a very widely spaced companion that’s easy to see in binoculars. The star also hosts at least one ring of glowing dust and debris left over from its birth. And where there’s dust, there may very well be planets… [Read more…] about The Lonely Star of Autumn

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