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The Caldwell Objects

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Eta Carinae Nebula. But remember that photographs<br />

of other emission nebulae — Barnard's<br />

Loop, say, or the California Nebula — make<br />

those nebulae appear much brighter than they do<br />

to the eye. I remained unsure of IC 2948's<br />

visibility until I observed Collinder 249 with<br />

binoculars and David Levy's 3½-inch Questar<br />

under dark African skies in lune 2001. <strong>The</strong><br />

nebulosity was apparent in both instruments as a<br />

dim fog that swelled into view under averted<br />

vision.<br />

From Hawaii my 4-inch refractor reveals a<br />

quite obvious circular patch of nebulosity (IC<br />

2944) around Lambda Centauri at 23x. Under<br />

averted vision a dim elliptical extension can be<br />

followed to the north, where it encounters a<br />

roughly lOth-magnitude star 7' away. This<br />

observation agrees with Volume 7 of the Webb<br />

Society Deep-Sky Observer's Handbook, which<br />

describes the nebula as "oval... of about 10' to<br />

15' extent, surrounding λ Centauri." I also suspected<br />

the presence of nebulosity around the<br />

brightest stars and star chains to the southeast<br />

100<br />

of Lambda Centauri.<br />

At 72x many pairs of stars can be seen<br />

throughout Collinder 249, which is most strongly<br />

concentrated about 25' southeast of Lambda<br />

Centauri. An obvious U-shaped asterism marks<br />

the chain's southeastern end. (Collinder recorded<br />

the cluster as a "chain of bright stars with<br />

nebulosity.") <strong>The</strong> cluster's stars then spread out in<br />

two diverging forks to the northwest, each of<br />

which ends at a bright pair of binocular suns. <strong>The</strong><br />

beauty of this star chain notwithstanding,<br />

Collinder's suggestion that this cluster is a<br />

Southern Pleiades seems unfounded. My<br />

eyepiece views certainly did not give such an<br />

impression. Perhaps in photographs, where the<br />

cluster's stars are embedded in a complex<br />

network of nebulosity, one could see how<br />

Collinder derived such a name. But I have to<br />

wonder. You see, IC 2602 (<strong>Caldwell</strong> 102) in<br />

Carina, which lies about 6° southwest of Lambda<br />

Centauri, is popularly known as the Southern<br />

Pleiades. Did Collinder mix up these clusters'<br />

names?<br />

<strong>The</strong> <strong>Caldwell</strong> <strong>Objects</strong> 401

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