Cosmic Pursuits

Basic astronomy and night sky information

Recent Astronomy Articles at Cosmic Pursuits

Seeing Carbon Stars, Close Up and Far

by Brian Ventrudo Filed Under: Deep Sky

his ALMA image reveals much finer structure in the U Antliae shell than has previously been possible. Around 2700 years ago, U Antliae went through a short period of rapid mass loss. During this period of only a few hundred years, the material making up the shell seen in the new ALMA data was ejected at high speed. Examination of this shell in further detail also shows some evidence of thin, wispy clouds known as filamentary substructures. Credit: ALMA (ESO/NAOJ/NRAO)/F. Kerschbaum

Many experienced stargazers are connoisseurs of carbon stars, deep-red and highly evolved stars that are dredging up carbon and other nuclear reactants from their innards on their way to becoming, briefly, planetary nebulae. These striking stars are the most colorful of all celestial sights and they’ve long intrigued astronomers who are trying to fine tune their theories of how stars come to the end of their lives. Carbon stars are too far away to reveal much detail directly, so astronomers study them indirectly by examining their spectra. But a team of researchers at the remarkable ALMA telescope in northern Chile have captured an amazingly beautiful and revealing image of a carbon star in the constellation Antlia. Let’s have a look at what they saw, then set some time aside to go see a carbon star for ourselves with a small telescope or pair of binoculars [Read more…] about Seeing Carbon Stars, Close Up and Far

Share This:
Facebooktwitterredditpinterestlinkedinmail

A Stroll Through the Stars of Capricorn

by Brian Ventrudo Filed Under: Deep Sky

The globular cluster Messier 30 as captured by the Hubble Space Telescope. Credit: NASA/HST.

Along the path of the zodiac, just east and a little north of Sagittarius, lies the smile-shaped constellation Capricornus. After the gaudy splendors of Sagittarius and other northern summer constellations, Capricornus isn’t much to look at. It’s the smallest constellation of the zodiac and the second-faintest after Cancer. It has just two stars brighter than 4th magnitude, so it’s a challenge to see this constellation in the city. But Capricornus offers several splendid alignments of stars that make for excellent viewing with a pair of binoculars on nights in August through October. Let’s have a look… [Read more…] about A Stroll Through the Stars of Capricorn

Share This:
Facebooktwitterredditpinterestlinkedinmail

The Sky This Month – September 2017

by Brian Ventrudo Filed Under: Celestial Events

The eastern sky well after midnight in early September showing the stars of the constellations Perseus and Taurus. Credit: Brian Ventrudo.

The month of September affords stargazers a last chance to see the Milky Way and all its attendant splendors. The rich constellations of Scorpius and Sagittarius are setting for the year, moving a little westward each night, but the lengthening nights keep these stars accessible for a little longer, at least for observers in the northern hemisphere. Southern observers still enjoy the thickest part of the Milky Way almost overhead. In the east, the relatively star-poor constellations of Pegasus, Capricornus, and Piscis Austrinus are moving into view. Observers with very dark sky get the chance this month to see the zodiacal light, a faint wedge of white sunlight reflected from fine dust in the inner solar system.  Also this month, low in the southwestern sky at sunset, Jupiter slowly fades from view while Saturn still hangs on, its rings casting dramatic shadows on the disk of the planet. Mercury makes its best showing of the year in the eastern sky before dawn. And the Sun crosses the celestial equator heading south, marking a change of seasons.  Here’s what to see in the night sky this month…

4 Sept. Neptune reaches opposition today. This blue-green ice giant, the most distance major planet from the Sun in our solar system, shines at magnitude 7.8 and spans an apparent diameter of 2.4″. Its tiny disk is visible in the constellation Aquarius less than 1º east-southeast of the orange 4th magnitude star Hydor (λ Aquarii). While the planet is plenty bright enough to see with a telescope, or even binoculars, resolving its disk requires some magnification, at least 75x to 100x. The planet’s disk gets larger with more magnification while the images of the stars do not. Visually, the planet has a very pale blue-green color [Read more…] about The Sky This Month – September 2017

Share This:
Facebooktwitterredditpinterestlinkedinmail

Field Notes from a First-Time Eclipse Watcher

by Brian Ventrudo Filed Under: Solar System

An anxious astronomer awaits totality.

“Dad, you finally saw a total solar eclipse. Now you’re a real astronomer”, said my younger daughter in the minutes after the August 21 eclipse.

It was a joke, of course, but I still winced. This was a sore point with me. Forty-five years of stargazing, on and off, and I’d seen thousands of sights in the sky from earthbound satellites to the Moon, from icy flotsam from the outer solar system to the colorful cloud bands of Jupiter, and all manner of wonders of the deep sky including galaxies billions of years older than our solar system. But I’d never seen a total solar eclipse [Read more…] about Field Notes from a First-Time Eclipse Watcher

Share This:
Facebooktwitterredditpinterestlinkedinmail

Touring the Heart of the Milky Way – Part 2

by Brian Ventrudo Filed Under: Deep Sky

A look at the deep-sky objects in and around Sagittarius covered in this tour. Objects in white font are covered in this tour. Objects in blue font were covered in the last tour. Click to open in a new tab.

Last week, you began a tour of some of the finer sights in and around the Milky Way in the constellation Sagittarius. This week, let’s look slightly westward to see another handful of splendid sights along the Sagittarius Arm of the Milky Way. The tour follows the objects in the white font in the above image. Those in blue font were covered in last week’s tour.

The base of operations for this tour is the grand constellation Scorpius, the Scorpion. The long, winding constellation is one of the few that obviously resembles its namesake. The claws of the fearsome celestial arachnid face westward towards the relatively sparse star fields of the constellation Libra. At the heart of the scorpion lies the bright red-orange supergiant star Antares. And to the east lies the winding tail that passes through increasingly rich star fields towards the heart of the Milky Way Galaxy [Read more…] about Touring the Heart of the Milky Way – Part 2

Share This:
Facebooktwitterredditpinterestlinkedinmail