Here is the transcript for my podcast about how to see the constellation Delphinus, the Double Double, and the Blue Snowball during the next few days.
Check out the Astronomy.com's interactive star chart to see an accurate map of your sky. It'll help you locate some of this week's key targets. Astronomy magazine subscribers have access to a slew of cool functions with StarDome PLUS.
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The constellation Delphinus, the Double Double, and the Blue Snowball are visible in the next few days. We’ll help you find them in this week’s Astronomy magazine podcast.
Hello, I’m Astronomy magazine senior editor Michael Bakich. Each week, I highlight three different night-sky targets for you to see:
One object you can find without optical aid;
One object to find with a small telescope; and
One deep-sky object to find with an 8-inch or larger telescope for you avid astronomers.
The solitary dolphin
Our first object once again uses the podcast in which I helped you locate the Summer Triangle — Vega, Altair, and Deneb — as a starting point. Find Altair and look about 15° to the east-northeast (or, to the star’s upper-left in the sky).
Here, you’ll find a small group of four medium-bright stars that looks like a crooked box. This is Delphinus the Dolphin. It’s a small constellation — it ranks 69th in size out of the 88 constellations that cover the sky — but that may make it easier for you to identify. To see the Dolphin’s tail, just add the 4th-magnitude star 3 1/2° to the south-southwest.
A double binary star
Our second object will surprise you through a small telescope. It’s the star Epsilon Lyrae, but most observers call it the Double Double. As the name indicates, Epsilon is a pair of double stars that lie close together.
You’ll find Epsilon easily. It sits 1.7° east-northeast of Vega. Through binoculars, you’ll see the initial double nature of this object, and you might think, “Ah, a double star.” You’re half right.
Point a telescope toward it, and you’ll see both “stars” resolve into pairs. To assure success, use a magnification above 75x. I’ve split both pairs many times through a 2.4-inch (60-millimeter) telescope.
Autumn’s snowball
If you use an 8-inch or larger telescope, look in the northern part of the constellation Andromeda for a planetary nebula called the Blue Snowball. You’ll see immediately why astronomers gave it that name.
The Blue Snowball shines at magnitude 9. Luckily, its light isn’t spread out over a large area. NGC 7662 — another name for the Blue Snowball — measures only 2.2'. This small size concentrates the planetary’s light, allowing it to trigger your eyes’ color receptors. If you’re looking for (or wanting to show somebody) color in a deep-sky object, look no further than the Blue Snowball.
That being said, different observers have described it as pale blue, faint blue, light blue, Robin’s-egg blue, slightly blue, whitish-blue, and, occasionally, various shades of light green. What’s more, nobody’s wrong. Each of us has our own sense of color perception, and it may differ a little or a lot from the observer next in line.
Through an 8-inch scope, the Blue Snowball appears as a small, evenly illuminated disk. You won’t see the 13th-magnitude central star in anything less than a 16-inch scope, so search for other details, like the nebula’s rich inner structure.
Look for a bright ring of gas surrounding NGC 7662’s hollow center. A fainter gas shell — tough to see — encompasses the ring. The ring’s brightest areas lie to the northeast and southwest. At magnifications above 300x, the brightness of the shell drops quickly near its edge.
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Read last week's transcript: September 5, 2008: The Scutum Star Cloud, the Wild Duck Cluster, and Barnard’s Galaxy
Listen to last week's podcast.