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The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199

March 31–April 7, 2016: The double star 54 Leonis offers small-telescope owners a nice view, while large-telescope owners can seek out spiral galaxy NGC 3198 in Ursa Major and emission nebula NGC 3199 in Carina.
You can find mission nebula NGC 3199, which lies in Carina the Keel, 4.4° southeast of magnitude 3.5 Phi (φ) Velorum.
Astronomy: Roen Kelly
Each week, Astronomy magazine Senior Editor Michael E. Bakich, a master at explaining how to observe, posts a podcast about three or more objects or events you can see in the sky.

Targets for March 31–April 7, 2016

Small telescope: Double star 54 Leonis
Large telescope: Spiral galaxy NGC 3198
Large telescope: Emission nebula NGC 3199
Downloadable File(s)

What hue do you view?
This week’s small-telescope target is one of Leo the Lion’s best double stars — 54 Leonis. To find it, point your telescope 6° northwest of magnitude 2.6 Zosma (Delta [δ] Leonis). The double star sits right on Leo’s border with Leo Minor.

You’ll love the color contrast here. Most observers see the magnitude 4.5 primary as off-white and the magnitude 6.3 secondary as deep blue. Some amateur astronomers, however, have reported the primary as a pale or robin’s-egg blue. Whatever hue you see, even a 3-inch telescope will separate the two stars, which lie 6.5" apart.

Bear-y good spiral
This week’s first large-scope object is spiral galaxy NGC 3198 in Ursa Major the Great Bear.

This object lies 2.7° north of magnitude 3.5 Tania Borealis (Lambda [λ] Ursae Majoris). It glows at magnitude 10.2 and measures 8.5' by 3.3'.

Through a 6-inch telescope, you’ll see an irregularly illuminated oval that appears more than twice as long as it is wide oriented northeast to southwest. A 14-inch scope at 300x shows lots of detail. A small, bright central region lies within an irregular halo that looks like truncated spiral arms. Only 2' north of the northeastern tip lies the magnitude 11.2 star GSC 3435:470.

The “C” in Carina
This week’s second large-telescope target is one some of you might have to travel south to see. It’s emission nebula NGC 3199 in the constellation Carina the Keel.

Look for this target 4.4° southeast of magnitude 3.5 Phi (φ) Velorum. It spans 20' by 15'. Through most telescopes, this nebula looks like a large, thick crescent that opens toward the east. Use a nebula filter for the best view.

Only the largest amateur instruments show some of the additional nebulosity that fills in a roughly circular shape. Near the crescent’s center lies the Wolf-Rayet star HD 89358, a massive, hot sun that generates lots of ultraviolet radiation and an intense stellar wind. In this case, the Wolf-Rayet star is sculpting out the gas surrounding it.

Expand your observing at

The Sky this Week
Get a daily digest of celestial events coming soon to a sky near you.

Observing Basics
Find more guidance from Senior Editor Michael E. Bakich with his Observing Basics video series.


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