Stardate:05:20:98
Spring's Treasure Chest of Galaxies
Springtime offers sunshine, birds, and the smell
of new mown grass. It also offers a wealth of galaxies, spread throughout
the constellations of Virgo and the lesser known Coma Bernecies. We began
last week to explore this treasure trove of galaxies, but there is far
too many wonderful objects to view in this area of the sky to explore in
one, or even two weeks. This is truly springs treasure chest of galaxies.
This week, we will once again set our gaze upon
the southern sky, and our minds upon these "island universes".
We will begin our journey at one end of this apparent chain of galaxies
exactly opposite of where we began last week, and journey inwards, ending
this week near the middle of this large collection of nightime jewels.
Some evening this week, go outside, and face the
southern horizon. At 9 pm, soon after the setting of the Sun, look 65 degrees
above the horizon. A large pair of binoculars or a modest telescope should
reveal a round galaxy, with a bright core. This galaxy was first cataloged
by Charles Messier, and so is known as M85, or Messier object number 85.
When William Herschel, the discoverer of the planet Uranus, was cataloging
his list of what were then only known to be fuzzy objects, or nebulae,
he also saw this object, and called it NGC 4392. NGC stands for New General
Catalog, Herschel's compilation of thousands of distant galaxies and nebula.
Slightly more than a degree down towards the horizon,
and just barely to the east lies NGC 4450. This is an elongated galaxy,
with a bright central core. Slightly dimmer than M85, this object, 1/12
of a degree across, shines at magnitude 10.
From here, turn your sights one degree to the
east, and one degree further down to the horizon. This is the home of M100,
otherwise known as NGC 4321. It is a round galaxy, at magnitude 9.4, it
is nearly twice as bright as our last object, NGC 4450. At 7 arcminutes
across, we can easily calculate that in a telescope whose field of view
is one degree across, M100 would fill up about 11 percent of the distance
across our field of view.
Now travel diagonally downwards, and a little
bit west. Here lies our next object, M99, better known as the Pinwheel
galaxy. The Pinwheel, otherwise known as NGC 4254, has a brightness between
that of M100 and NGC 4450. M99 is a spiral galaxy, much like our own Milky
Way in structure. This is about 1/12 of a degree, or 5 arcminutes in diameter.
Next, travel about one degree to the west, and
nearly one degree up from the horizon. The eliptical galaxy which lies
here is M98. Eliptical galaxies are strange, egg shaped galaxies, and M98
bears a bright central core.
Now, point your gaze two degrees nearly straight
down to the horizon. Here we find another elliptical galaxy NGC 4216. At
magnitude 10, it is the dimmest of this week's objects. This galaxy may
appear dim, but it appears a respectable 8.3 arcminutes, or 1/7 of a degree
across. At this point, you should be nearly exactly 60 off the southern
horizon.
Next week, we will continue our journey through
this dense forest of galaxies, and at the end of this series, we will end
up right where we began last week.