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at a meeting of the Royal Astronomical Society. The
audience was eager to witness the latest example of
his photographic prowess. Roberts obliged by showing
a lantern slide of his three-hour exposure of the
starry nebular complex NGC 2264, which surrounds
the 4.6-magnitude star 15 Monocerotis. Among the
prominent features was a “conical dark space bounded
by a rim of nebulosity” — the now-famous Cone
Nebula — just south of a larger, triangular bevy of
stars now named the Christmas Tree Cluster.
Roberts then projected a second lantern slide of
the same region, this one from a glass photographic
positive that had recently arrived from the United
States. The photographer — Lick Observatory’s
Edward Emerson Barnard — was, like himself, a
widely acknowledged expert in astronomical imaging.
Although the pair of images depicted identical regions,
they looked distinctly different. The stars in Roberts’
photograph, taken with his 50-cm telescope, were
virtual pinpoints. Those in Barnard’s picture, taken
with Lick’s 15-cm, f/5.2 wide-field Willard camera,
appeared as bloated disks.
Roberts acknowledged that he had enlarged
Barnard’s photograph fivefold to match the scale of
his own. He had done so to make a point. The profuse
“nebulosity” depicted in Barnard’s image was illusory,
he argued; it stemmed from the poor resolution of the
Willard camera, which captured large swaths of sky
at a highly compressed scale. Through his own 50-cm
reflector, he said, the purported nebulous glows and
swirls in the star cluster are seen for what they are:
aggregations of faint stars, entirely beyond the feeble
light grasp of Barnard’s little instrument.
Unwittingly or not, Isaac Roberts had fired a
transatlantic salvo from an amateur astronomer’s
station south of London into the heart of a professional
research institution in California. The return volley
from Barnard was not long in coming.
E. E. Barnard was the product of an impoverished
upbringing in Tennessee during the Civil War. He
was a high-strung workaholic who had had just two
months of formal schooling before he took a job as a
studio photographer’s assistant at age nine. Barnard
learned astronomy in his teens from Thomas Dick’s
popular handbook The Practical Astronomer. He
became a passionate hunter of comets, discovering 16
of them altogether, and built a house for himself and
his bride with the reward money that was offered at
the time to comet finders.
In 1888, after a five-year stint as a non-degree
student and observatory manager at Vanderbilt
University, Barnard joined the staff of the new Lick
Observatory in California. It was here, in 1892, that he

Fox Fur Nebula

Cone Nebula

15 Mon

MODERN CONFIRMATION Today, backyard amateurs with modest gear

far surpass the greatest astrophotographers of 120 years ago. Even without

narrowband filters, the intricate clouds around 15 Monocerotis (S Monocerotis)

and the Cone Nebula stand brilliantly revealed in Andrew Lecher’s stack of 54

ten-minute exposures. He took 18 each through red, green and blue filters. The

frame is 1° tall, with north up. The upside-down Christmas Tree asterism spans

most of the nebula, with 15 Mon as the tree’s base and the bright star just

north of the Cone Nebula as its tip.