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A gem of a cluster.

MANY OBSERVERS rate the Eta Carinae Nebula as the greatest spectacle in the southern Milky Way. Indeed, the nebula's presence is so overpowering it can be easy to miss other nearby treats. One of these is NGC 3293, the Gem Cluster.

Recent studies indicate that most of the clusters in and around the Eta Carinae Nebula are about 9,000 light-years distant and part of the immense Carina OB 1 complex. The Gem Cluster is no exception, situated only 1 1/2[degrees] from the glowing heart of Eta Carinae.

At magnitude 4.7, the Gem is a naked-eye target under dark, rural skies. When viewed in 10 x 50 binoculars, the cluster appears as a very bright, small, hazy spot with a few sparkles sewn in. My 15 x 70s reveal several additional stars, including a 9.7-magnitude glint of gold on the cluster's northeast edge. But the grouping's compact nature makes it difficult to resolve much more.

NGC 3293 is certainly an interesting binocular sight, but imagine what it might look like from inside. Of the cluster's 300 stars, more than 75 are O- and B-class giants and supergiants 10 to 30 times more massive than our Sun and tens of thousands of times more luminous. If you could view the night sky from a planet orbiting one of these gems, you would find each constellation sporting at least one star as bright as Venus and several more comparable to Sirius. Best of all, more than half the sky would be filled with a close-up view of the Eta Carinae complex. Now that's a binocular highlight to contemplate!

Using the Star Chart


Late May         7 p.m.
Early May        8 p.m.
Late April       9 p.m.
Early April      10 p.m.
Late March       11 p.m.

These are standard times.


Go outside within an hour or so of a time listed above. Hold the map out in front of you and turn it around so the label for the direction you're facing (such as west or northeast) is right-side up. The curved edge represents the horizon, and the stars above it on the map now match the stars in front of you in the sky. The center of the map is the zenith, the point in the sky directly overhead.

Example: Turn the map so the label "Facing West" is right-side up. Almost halfway from there to the map's center is the bright star Sirius. Go out and look west nearly halfway from horizontal to straight up. There's Sirius!

Note: The map is plotted for 35[degrees] south latitude (for example, Sydney, Buenos Aires, Cape Town). If you're far north of there, stars in the northern part of the sky will be higher and stars in the south lower. Far south of 35[degrees] the reverse is true. Jupiter, Saturn, and Venus are positioned for mid-May.


You can get a sky chart customized for your location at any time at observing/skychart

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No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2007 Gale, Cengage Learning. All rights reserved.

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Title Annotation:southern binocular highlight
Author:Dalrymple, Les
Publication:Sky & Telescope
Geographic Code:1USA
Date:May 1, 2007
Previous Article:Treasures in Canes Venatici.
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