Cosmic Pursuits

Basic astronomy and night sky information

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.

Star Factories in Cepheus

by Brian Ventrudo Filed Under: Deep Sky

A deep-field H-alpha image of a small region in Cepheus, about 7 degrees on each edge, showing the nebula IC 1396 surrounding the star cluster Trumpler 37 at lower right and the ‘Flying Bat’ nebula, Sh2-129, at the upper left of the image.

This month we turn our gaze to a field of view about 7o square in the crooked-house of the constellation Cepheus. The field is a little smaller than your closed fist held at arm’s length. In the image above, captured in H-alpha with a small monochrome astronomy camera and a 90 mm lens, you see in this field a pair of spectacular emission nebulae, an embedded star cluster, half-dozen dark nebulae hiding regions of new star formation, and a blazing late-stage star on the verge of blowing itself to bits. [Read more…] about Star Factories in Cepheus

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A Deep-Sky Vista and the Dark Nebula Le Gentil 3

by Brian Ventrudo Filed Under: Deep Sky

The North America Nebula (lower left) and IC1396 (upper right). The dark form of Le Gentil 3 lies just right and below center in this image.

Every picture tells a story, and this wide-field image of the northern Milky Way in Cygnus and Cepheus, which spans nearly 16º on each edge, surely has a lot going on.

To the upper right of this image, you see the blossom-like emission nebula IC1396 in Cepheus with the aging red-orange star μ Cephei, the ‘Garnet Star’, on its limb. Plenty of stars are forming within this stellar nursery.

At the upper left, you see the tiny blossom of the Cocoon Nebula (IC 5146), another stellar nursery at the end of a two-degree-long dark nebula Barnard 168, both set in a rich field of background stars.

Moving down the left side of the image you see more nebulosity culminating in the unmistakable North America Nebula (NGC 7000) and the neighbouring Pelican Nebula (IC 5070) below, both of which encompass more active regions of star formation. Various patches of dark dust and distant star clouds, especially the square formation above NGC 7000 also lie within this wide view, as does the bright star Deneb at the tail of Cygnus, the Swan.

But the showpiece of this image is notable for its lack of light. Just right and below centre you see the vast and irregular void of a cloud of gas and interstellar dust known as Le Gentil 3 that comprises an immense conglomeration of star-making material in the early stages of giving birth to dozens of new star clusters.

[Read more…] about A Deep-Sky Vista and the Dark Nebula Le Gentil 3

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Five Fall Double Stars for a Small Telescope

by Brian Ventrudo Filed Under: Deep Sky

Albireo (Beta Cygni). Image credit: Jared Smith via Flickr under Creative Commons license.

Galaxies abound in the deep sky of northern autumn and imagers and visual observers with big telescopes and dark sky have plenty of choice targets. But for us urban visual observers with smaller scopes, galaxies, despite shining with the combined light of several hundred million stars, usually look a little underwhelming. So what’s left to see? Double stars, of course! Often overlooked for flashier sights, double (and multiple) stars offer a great challenge, contrasting colours, and understated but still gasp-worthy beauty that doesn’t take long to appreciate. Here are five superb double stars for northern autumn observers that will make you a fan of these under appreciated objects, listed approximately in order of easiest to hardest to observe [Read more…] about Five Fall Double Stars for a Small Telescope

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The Cygnus Star Cloud

by Brian Ventrudo Filed Under: Deep Sky

The constellations Cygnus and Lyra and the northern Milky Way and Great Rift. The Cygnus Star Cloud lies in a diagonal near center, with Deneb and the North America Nebula at upper left and Vega at upper right. Sadr and IC1318 lie to the left and above center. Image credit and copyright: Brian Ventrudo/CosmicPursuits.com.

As northern summer nights grow longer in August and September, the big constellation Cygnus lies nearly overhead before midnight and offers dozens of colorful nebulae and star clusters for visual observers and astrophotographers. The newly discovered Radcliffe Wave begins here. So does the dark and dusty Great Rift that splits the band of Milky Way in two. Cygnus also contains the brightest section of the northern Milky Way in the grand Cygnus Star Cloud, the most prominent star cloud north of the celestial equator. With a pair of low-power binoculars or with just your dark-adapted eyes, this billowing collection of millions of stars along an arm of our galaxy offers as beautiful a sight as any earthly work of art or nature [Read more…] about The Cygnus Star Cloud

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An Exploding Star in Messier 101

by Brian Ventrudo Filed Under: Deep Sky, Science

An image of the galaxy Messier 101 and the supernova SN2023ixf next to the emission nebula NGC 5461. Captured on May 20, 2023. Image credit – Florian Rünger/Wikipedia Commons.

A big star exploded as a supernova in the lovely face-on spiral M101 in Ursa Major this month. At a distance of 20 million light years, this is the closest supernova in five years and the first in this galaxy since 2011. The new supernova isn’t close enough to see with the unaided eye, alas, but it lies within reach of a 5” or larger telescope for visual observers (as of the end of May 2023) and it offers an easy target for imagers. [Read more…] about An Exploding Star in Messier 101

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