http://www.skyandtelescope.com.au 51As stone lions often flank the stairways
to palaces and museums, so Leo watches
over the grand entrance to the land of the
galaxies.
— Leland S. Copeland,
Sky & Telescope, May 1942L
eo leads a procession of springtime
constellations greatly renowned for
the teeming swarms of stars that
we call galaxies. Leo itself harbours 809
galaxies from the New General Catalogue
(NGC), five of them previously listed
in Charles Messier’s catalogue. For this
foray into the night sky, we’re going
to turn our gaze toward three of those
bearing Messier designations and
assorted NGC escorts.
The members of our Messier galaxy
trio were discovered with a 75-mm
refractor by Charles Messier’s colleague,Pierre Méchain. Méchain found the
first two, Messier 95 and Messier 96,
on May 20, 1781. He spotted nearby
Messier 105 shortly thereafter, yet too
late for inclusion in the final version of
Messier’s catalogue. However, Méchain
sent a letter about his tardy catches to
Johann Bernoulli III, and extracts were
printed in two publications of the Berlin
Royal Academy of Sciences and Arts.
In part, the letter reads: “Mr. Messier
reported... two nebulae that I discovered
in Leo... but there is a third farther
north; it is more beautiful than the
other 2; I discovered it March 24, 1781.”
Examining Méchain’s little-known
letter in 1947, Helen Sawyer Hogg was
able to identify this nebula as NGC- She also recognised two of the
others as NGC 4258 and NGC 6171.
In the Journal of the Royal Astronomical
The lion-guarded gate
You’ll need to brave a ferocious beast to find these deep sky treasures in Leo.
Society of Canada, Sawyer Hogg wrote
that in her opinion they should be
added to the Messier list as M105,
M106 and M107 — and they were. But
what a difference a few days between
discoveries made! M95 and M96 joined
the ranks of the Messier objects in 1781,
while M105 had to wait another 166
years to make the list.
All the galaxies in this tour are
gathered into an area about 2¼° across,
just south of 52 Leonis. When I aim
my 18×50 image-stabilised binoculars
that way, the trio of Messier galaxies
is nicely visible. M105 and M96
are fairly obvious, each clutching a
brighter centre. M95 is dimmer, with a
distracting star close to its western side.
Through my 130-mm refractor
at 37×, M105’s roundish face grows
much brighter toward the centre. Just
7 ′ east-northeast of M105, NGC 3384
joins the scene as an elongated oval
pointed toward M105. This companion
galaxy boasts a bright, round core and
a tiny, vivid nucleus. M96 and M95
each appear oval. M96 rises markedly
in brightness toward the centre, while
M95 hosts a fairly bright interior with a
small, brighter core.
At a magnification of 63×, NGC 3389
emerges 6′ south-southeast of NGC
3384 and is elongated toward M105.
The smallest of the five galaxies, NGC
3389 displays a dim façade of uniform
surface brightness, but at 91× the little
galaxy does seem to have a slightly
brighter central area.
Studying the other galaxies at
91 ×, I see that M105 becomes slightly
oval, pointed toward NGC 3384, and
bears a small, radiant heart. NGC
3384 is comparable in apparent size
and brightness to M105, and I’m a
bit surprised that Méchain didn’t
note this galaxy along with M105.
M96 shows three stages of brightness:3338UGC 5832M9533573367M963377M1053384
338933913412341952HD 93273LEO10 h 40 m+14°10 h 50 m 10 h 45 m+13°+12°Star magnitudes768
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10by Sue French TARGETS