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POSS-II / CALTECH / STSCI / PALOMAR OBSERVATORY

FEBRUARY 2020 OBSERVING
Deep-Sky Wonders by Sue French

Orion’s

Golden

Shield

Remarkable clusters

and nebulae encircle

the giant’s torso.

His sword hung gleaming by his side,

And, on his arm, the lion’s hide

Scattered across the midnight air

The golden radiance of its hair.

— Henry Wadsworth Longfellow,

The Occultation of Orion

I

n this column, we’ve explored some

of the amazing deep-sky wonders in

the environs of Orion’s gleaming sword.

Now let’s set our sights a bit farther

north, starting in the mighty Hunter’s

shield, which is often portrayed as a

golden lion pelt draped over Orion’s

outstretched arm.

We fi nd an aptly seasonal Valentine’s

Day treat 1.8° west-northwest of Pi^1

(π^1 ) Orionis, atop Orion’s shield. The

open cluster NGC 1662 is a heart-

shaped beauty you could share with

someone special.

My 130-mm (5.1-inch) refractor at

23 × shows 22 stars in NGC 1662, all

but four outlining a stylized heart with

a loop where the lobes meet. The clus-

ter’s two brightest stars have a yellow

hue; one ornaments the loop and the

other shines at the top of the heart. The

four loop stars belong to the multiple

star h684, and a dimmer, fi fth compo-

nent becomes visible at high powers.

The light from this Valentine heart

has traveled about 1,400 years to reach

your eyes, starting approximately two

centuries after the feast of St. Valentine

was established.

Just southeast of NGC 1662, we

fi nd the possible open-cluster remnant

Alessi 29, discovered by Brazilian

amateur Bruno Sampaio Alessi. Open-

cluster remnants are the residue of

clusters that lost their gravitational grip

on most of their original members and

have been pared down to more stable

multiple systems. Such remnants are

diffi cult to identify unless they have

enough members to show a telltale

spectral sequence indicating their for-

mer glory as part of a larger group.

Visually through my 130-mm scope

at 63×, Alessi 29 is a teardrop of 13 stars

magnitude 9.7 and fainter. The glisten-

ing teardrop is 9½′ long and appears to

be falling from the northeast.

The bright, eye-catching asterism

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Elosser 1 sits halfway between Pi^2

and Pi^3 Orionis and just east of an

imaginary line connecting them. In the

mirror-reversed view of my 130-mm

refractor, Elosser 1 is a J of 13 stars

hooked around a golden 9th-magnitude

star. The brightest stars in the top and

bottom of the J glow yellow and orange,

respectively. At 63×, 15 faint stars are

visible within the J, fi lling it out into an

egg shape 21′ long.

North Carolina amateur David

Elosser chanced upon this group while

observing with his 4-inch refractor. It’s

now listed in the Deep Sky Hunters’

asterism catalog at https://is.gd/deep-

skyhunters. Elosser points out that the

two star-triangles at the southern end

of the group seem to form “an old-fash-

ioned rocket ship.”

Let’s work our way away from the

shield to the pretty double star Rho (ρ)

Orionis. My 105-mm refractor at 87×

shows a bright, golden primary with a

much dimmer companion 6.9′′ to the

east-northeast.

The more equal and tighter pair 32

Orionis is pinned to Orion’s western

NGC 1662

Alessi 29