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Cosmic Challenge: Galaxies around M13
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Cosmic Challenge: Galaxies around M13
like me, you have probably seen Jupiter, Saturn, the Orion Nebula, and all of
the sky's showpiece objects more times than you can count. And while they are
truly spectacular and well worth revisiting, you may be looking for something
new, something challenging to observe.
That's the premise behind this new monthly e-column here on Cloudynights. Each month, we will look for objects that, quite honestly, many amateurs don't even know exist!
Actually, the spark for Cosmic Challenge dates back nearly three decades, to a column I wrote in Deep Sky magazine entitled "Challenge Objects." That later evolved into my book, Cosmic Challenge (Cambridge University Press, 2010), and now as an offshoot, this column here on Cloudynights.
Of course, what qualifies as "challenging" is difficult to define. An object might be very faint, or very small, or tough to spot for any of a number of other reasons. Some require excellent sky transparency, while others need rock-steady seeing. So much also depends on each person's level of experience, the clarity and darkness of the observing site, and the telescope used.
To help level the playing field, each month will feature one of six instrument categories based on aperture: naked eye, binoculars (less than 70mm), giant binoculars and 3- to 5-inch (7.5-13 cm) telescopes, 6- to 9.25-inch (15-23.5 cm) telescopes, 10- to 14-inch (25-36 cm) telescopes, and 15-inchers (38 cm) and up. This month, for instance, is designed for 10- to 14-inch apertures, as you can see on the column's header. Next month, who knows.
Before we begin, let me give you one word of advice: Patience! Unless you have the time to concentrate on the hunt, to stop and pull back to clear your mind before diving back in, then Cosmic Challenge may prove frustrating. These targets are not suitable for quick viewing sessions. Most can only be seen after patient searching for many minutes -- indeed, sometimes hours -- on end.
Above: Summer star map from Star Watch by Phil Harrington.
Above: Finder chart for this month's Cosmic Challenge.
Chart adapted from Cosmic
Challenge by Phil Harrington.
I’m sure that most of us have seen M13, the Great Hercules Globular Cluster, through many different binoculars, telescopes, and maybe even by eye alone. It’s a real dazzler.
But have you ever look around M13 and examined its surroundings carefully? Within about a degree are six faint intergalactic members of the NGC and IC listings. They make fun challenges through 8- to 12-inch apertures, and even larger if light pollution is a little overwhelming.
brightest of the bunch is NGC
William Herschel discovered NGC 6207, but he missed IC 4617. Can you do better? You'll find it centered between NGC 6207 and M13, just touching the western side of a trapezoid of 13th-magnitude stars. This little cigar-shaped spiral is a fairly tough catch with my 18-inch from my suburban backyard, but is clearly visible through my 10-inch under better conditions. Aperture is great, but there is no substitution for dark skies.
If IC 4617 was a little too demanding, NGC 6196, the brightest of a trio of galaxies found about a degree southwest of the globular, should prove easier. Under dark skies, a 10-inch shows this 14th-magnitude target as a small, round glow highlighted by a brighter central core.
second, dimmer galactic smudge is nestled 6' to the southeast. The true
identity of this second object is IC 4616, although some references
identify it incorrectly as NGC 6197. The confusion dates back to
German-born astronomer Albert Marth (1828-1897). Marth came to
Next, try your luck with IC 4614, set 3' northwest of NGC 6196. Like IC 4616, IC 4614 is rated at 15th magnitude and takes a special night to be seen through even the largest backyard scopes.
The furthest west of the bunch is NGC 6194. Lying 1.1° west-southwest of M13, this little elliptical galaxy shines at 14th magnitude and spans just 1' across. You'll need at least 150x to see its small, amorphous glow.
Above: The view of (left to right) NGC 6194, IC 4614, NGC 6196, and IC 4616 through my 18-inch Newtonian.
Have a favorite challenge object of your own? I'd love to hear about it, as well as how you did with this month's test. Contact me through my web site or post to this e-column's discussion forum.
Remember, half of the fun is the thrill of the chase. Game on!
About the Author:
Phil Harrington writes the monthly Binocular Universe column in Astronomy magazine and is the author of 9 books on astronomy. Visit his web site at www.philharrington.net to learn more.
Phil Harrington's Cosmic Challenge is copyright 2016 by Philip S. Harrington. All rights reserved. No reproduction, in whole or in part, beyond single copies for use by an individual, is permitted without written permission of the copyright holder.
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