In this introduction to the night sky, you
can get a start on being able to recognize some stars and constellations
that are available to us on any clear night. Learning some of the constellations is the first step in locating
the many beautiful objects of the night sky.
Although the night sky is most beautiful
away from the light pollution of the city, don't let that stop you from
getting a start on learning the sky. A quiet, safe place like a park or
soccer field away from blaring lights where you can see a good portion of
the sky is all you need.
We will begin with the most familiar summer
constellations and stars in the Northern Hemisphere, as most people and
families are out and about during these warm months of June through
September.
But first, a few words about equipment and
supplies: To begin your
journey, you will definitely need a map (star chart) and a source of light
to see it with. A compass
might be a good thing to bring along as well,
until you can easily find north by using the stars (our first lesson)!
A flashlight is needed so you can see in
the dark to read your star chart. Unfortunately, standard white light flashlights are too bright and
ruin your night vision, so we make a compromise. Red light is much better than white light since it affects night
vision the least. So, tape some red construction paper, several layers of
red cellophane, or several layers of red tail-light tape over the front of
the flashlight lens. You could
also paint the bulb or the lens with red finger nail polish or red paint. It usually takes quite a few layers and needs to be dimmer than you
would think, so test it in the dark. It only needs to be light enough to see your chart. Best, of course, is to buy or build a red LED light for astronomy. Red light is the only light to use at a star party.
A book of constellations or set of star
charts is the next important item. “Nightwatch” by Terrance Dickenson is a
good introductory book on general astronomy and it is includes great
constellation charts. A
circular star finder, called a Planisphere, will show the stars and
constellations for the entire year. You just rotate the circles to match
the date and the time, and it will show you the constellations and bright
stars that are up for that period of time. Get the big, plastic ones. They
come in different latitudes, so check to see if it's close to where you
live. ( Portland
is located at approximately 45.5 degrees north.) A good guide to identifying star patterns into constellations is a
book called “The Constellations: A New Way
to See them” by H. A. Rey (also author of the “Curious George the Monkey”
series).
Warm clothes are a must, especially with
children. It is surprising that even in the warm summertime, the night air
can be cold when you are standing around looking at the stars. Also, bring a bit to eat and/or something to drink if you are going
to be out for a while. Bring a chair as well.
Get your feet wet at a local Star Party.
Check out the RCA Star
parties or your local astronomy club for the dates and times.
Besides getting expert help in identifying constellations, stars, and
objects, you can also check out various telescopes and get a look at a
number of beautiful objects of the night sky.
Stars and Constellations
Finding constellations and groups of stars
is enjoyable, and being acquainted with the sky will be invaluable upon
further exploration of the universe. Stars are giant balls of hydrogen gas that formed in gas clouds
like the Orion nebula. They have so much mass, that the pressure in the
deep interior is great enough to combine, or fuse, hydrogen atoms
together. This fusion yields a great deal of energy, some of which we can
see as visible light.
Stars come in great variety of sizes and
brightness, or luminosity. Their surface temperatures determine their
color. Very hot stars are blue or white, medium temperature stars like our
sun are yellow, with the red stars being the coolest. Very bright blue or
white stars can be much further away from us than cooler stars, even
though they appear closer, although red super giants can also be seen at
great distances from us.
Constellations are recognized patterns of
stars that form animals or figures, many named from very ancient times. It
is enjoyable to try to see the pattern form into something that has been
recognized and named for many centuries, many dating back to the Ancient
Egyptians and Babylonians.
The constellations also serve as a guide to
locating objects in the sky, and are regularly used today by both amateur
and professional astronomers. An astronomical object is usually spoken of
as being "in" a certain constellation. (The globular cluster M13 is found
in Hercules.)
Lesson 1 - Ursa Major (The Big Bear)
This is a
huge constellation in the Northern Sky, and is visible year round in
the Northern Hemisphere, although it is quite low in Autumn.
The most famous part of Ursa Major is
the Big Dipper. It consists of the dipper and the handle. To find it,
you first have to figure out where north is. This is where a compass
comes in handy. In the summer, the Big Dipper is in the Northwest sky,
with the handle pointing upwards.
Notice that the two stars that form the front part of the dipper point
to the North Star, Polaris. Now, when you have found Ursa
Major, you can find North. All the heavens rotate counterclockwise
very near this point (Polaris) due to the rotation of the earth.
In the second star from the end of the handle, you will see two stars
close together, Mizar and Alcor. They are known as an
optical double and are a nice pair in binoculars. The brighter white star
is Mizar. Star charts will show the
apparent magnitude of a star. Mizar is a 2nd magnitude star, and Alcor is
a 4th magnitude star. Mizar is also a true binary star, where two or more
stars orbit each other. More than 50% of all stars are binary systems.
Both Mizar and Alcor also have companion stars than cannot be detected
visually. Try to determine which stars in the Dipper
are dimmer or brighter than Mizar. Check on a chart of Ursa Major to see
the apparent magnitudes of these stars.
The other constellation streaming out from
Polaris is Ursa Minor, The Little Bear, or better known as The Little
Dipper. The stars that make up the handle, other than Polaris, are
difficult to see in the city. Try spotting the dipper stars.
|
 |
Next, we are going to "star-hop" across
the sky.
 |
Pretend the handle of the Big Dipper is an
arc that will lead you across the sky to the next bright yellow-orange
star, Arcturus, in the constellation Bootes, ( boh-OH-teez),
The Herdsman. Arcturus is a 0 magnitude star, and the 3rd brightest in the
sky. Bootes is shaped like a long kite. |
Next is the arc down to the blue-white star
Spica, in the Constellation
Virgo, The Virgin, the second largest constellation in the sky. |
 |
She holds a spike, (from the old English
term) of wheat in her left hand, with Spica, being the ear of wheat. Spica
is a 1st magnitude star. Notice that it probably is twinkling (or
scintillating) because the light has to travel through a lot of our
Earth's turbulent atmosphere as it is low in the sky in Summer, and
by September is below the western horizon. Virgo is famous for its
many galaxies, and best seen in Spring.
Remember
the saying: Arc to Arcturus and drive a spike to Spica. |
Lesson 2 - The Summer Milky Way
Now that we
have spanned the sky, let's return to Polaris, and then move to the
Northeast.
Here you will find the large "W" of Cassiopeia (Cas
ee oh PEE uh), the Queen, rising in the Northeast. Many fine open
clusters of stars are found here.
Below Cassiopeia near the horizon in
July, is the constellation Perseus, (PER see us), the Hero.
If you are in a dark sky away from city
lights, you will be able to see the dim glow of stars running through
these constellations. This hazy band is the Milky Way, our
Galaxy. As you follow this band of haze across the sky, you are
looking across part of the galaxy inside of which we live. Just a
simple scanning through this region with binoculars will give an
indication of the number of stars here.
Galileo was the first to record what he saw
through his telescope in a letter to the Tuscan Court on January 30, 1609.
"Besides the Moon, this spyglass has allowed me to discover a
multitude of fixed stars never before seen, of which there are more
than ten times as many as are naturally visible. Moreover, I have
assured myself about what has always been a controversy among the
philosophers, that is, what is the Milky Way."
|
 |
 |
Next, we come
to the constellation Cepheus, (See fee us) the King, and
husband to Cassiopeia.
Cepheus does not have any really bright stars
and may be difficult to pick out, especially if the sky is dark and
full of stars in the Milky Way.
Cepheus looks a bit like a house on its
side. Follow a line from the "top" stars of Cassiopeia, which will
point to Cepheus. Look for the steep roof pointed toward Ursa Major |
Continuing to head south, a much more
prominent constellation flying high overhead is Cygnus (SIG-nus),
the Swan, also known as the Northern Cross.
The brightest star is the tail of the
Swan, the alpha star of Cygnus, Deneb. Deneb (Arabic for tail) is very
distant (1400 light years) and still a very bright 1st magnitude star.
The middle or breast star of the swan is Sadr, a 2nd magnitude
star. This is the point where the wings are crossing the body.
Representing the bill of the swan is the
well known star Alberio. To the naked eye, Alberio appears to be a
single, naked-eye 3rd magnitude star, but when viewed through a telescope,
it separates into a truly beautiful binary star, one of the favorites of
many. Look closely at Alberio and
see if you can see that one star is blue and one is yellow.
Cygnus is especially beautiful in a dark
sky and is great territory for binocular exploration. Just cruise your instrument down
through the center of the constellation, and you can run into many star
clusters and swirls of stars.
|
 |
On the edge of the Milky Way and next to
Cygnus is the small constellation Lyra (LIE- rah), the Lyre (harp)
of Orpheus. The second brightest
star of the summer sky and the most well known resides in Lyra, the white
star Vega. It is a 0
magnitude star. It is not too distant at 27 light years.
The other stars making up Lyra's
distinctive shape are 3rd and 4th magnitude stars.
We come to another bird as we move towards
the south, the constellation Aquila (uh KWIL uh), the Eagle. In
Greek legend, Aquila held the thunderbolts of Zeus.
Aquila 's most noticeable feature is the
three stars forming a row. The
brightest star in the middle of these is the white, 1st magnitude star
Altair. Altair, with Deneb and Vega, form the Summer Triangle.
Now as we
follow the Milky Way to the southern horizon, we come to the highlight
of the summer, Sagittarius (sadge ih TARE ee us), the Archer. It's
pretty difficult to find an archer here, so Sagittarius is better known
for its more recognizable "teapot" shape, complete with a handle, spout,
and even a spoon nearby.
 |
Sagittarius is a truly a playground for the
summer observer. There are many star clouds and clusters, both Globular
Clusters and Open Clusters, as well as beautiful Nebulae. When you are looking at
Sagittarius, you are looking toward the center of our galaxy, 28,000 light
years away. If you have binoculars, cruising through Sagittarius is truly
a wonderland in a dark, moonless sky. If you find yourself wondering what
some of these fuzzy things are, you are ready for the next step.
For example, find the cap of the teapot,
and go to the very top star, zeta Sagittariae. Locate this in your
binoculars, and then move up and to the left. This fuzzy ball is the
Globular Cluster M22, a very beautiful sight in a telescope. Armed
with a star chart, you can locate many more objects, or just take in all
the stars in the rich areas near the center of the Milky Way.
To the west of Sagittarius is a
constellation that really looks like its namesake, Scorpius, the
Scorpion. The heart of Scorpius is the red supergiant star Antares.
If you replaced our sun with Antares, it would extend out to the orbit of
Mars!
|
There is another fine Globular Cluster near
Antares, the very beautiful M4. This is also visible in binoculars.
Find Antares, which is the brightest star in the south, then move your
binoculars west and south, and you should see another fuzzball of hundreds
of thousands of stars. M4 is not as condensed as M22, and you can see many
stars resolved with the humblest of telescopes.
This should get you started in exploring
the night sky. Check out the list of books and sky charts that will lead
you to the many wonders of the night sky. |