Download Spring and Summer Sky Observer

Spring and Summer Sky
Observer
Topic
Constellations can be used to help locate deep space objects in the
spring and summer skies.
Introduction
By learning the locations of constellations and stars, an amateur
astronomer can locate many difficult-to-see objects. Heavenly bodies that
cannot be seen without the aid of binoculars or a telescope are generally
known as deep-space objects. The many type of deep-space objects can
be categorized as galaxies, globular clusters, open clusters, and nebulae.
Galaxies are billions of stars held together by gravity. Some galaxies, like
our own Milky Way, have a flattened, circular shape and are described as
spiral. The Milky Way is about 100,000 light years in diameter and 1,000
light years deep at the slightly bulging center. A light year is the distance
light travels in a year, or about 5.9 million miles. Because Earth is part of
the Milky Way, we cannot view the entire structure. However, one side of
our galaxy is visible as a starry band across the night sky. Clusters are
groups of stars that are together in space. A globular cluster, which may
contain millions of stars, is much larger and denser than an open cluster.
The sizes of open clusters vary from tens to hundreds of stars. Nebulae
are clouds of dust and gas, often left when stars die.
Astronomers have been aware of deep-space objects since the earliest
telescopes were put to use. One of the most extensive listing of these
objects was compiled by Charles Messier between 1758 and 1782.
Messier was fascinated by comets and spent a lot of time searching the
sky for them. During his observations, he listed and described other
interesting points in deep space. This compilation is now known as the
Messier catalog.
In this experiment, you will locate several stars and constellations that
are common to the spring and summer skies, then use these to help you
locate some deep-space objects and double stars.
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SPRING AND SUMMER SKY OBSERVER
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Time Required
1 to 2 hours
Materials
✒ access to an outdoor area at night (as far from lights as
possible)
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✒
✒
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small telescope or binoculars
star chart (specific to the month)
red-filtered flashlight
compass
science notebook
Safety Note
Please review and follow the safety guidelines.
When outdoors, wear appropriate clothing, shoes, and coats for
the area and time of year.
Procedure
1.
2.
3.
4.
Follow your teacher to an outdoor area designated for star watching.
Use the compass, star chart, and red-filtered flashlight to orient
yourself to north, south, east, and west.
With the naked eye, locate the Milky Way, which appears as a large,
hazy region of stars and interstellar gas. Search for dark spots in
the Milky Way. These are dark nebula, places where cosmic dust
block light coming from distant stars.
With the naked eye, use your star chart to locate these
constellations and their bright stars:
a. Ursa Major. Literally named “Large Bear,” this constellation
contains the big dipper. The two front stars of the dipper (Dubhe
and Merak) point to Polaris, the North Star. The star at the end
of the handle of the big dipper is Alkaid (see Figure 1).
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SPRING AND SUMMER SKY OBSERVER
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Figure 1
b. Ursa Minor. This constellation, which looks like a small dipper, is
near Ursa Major.
c. Bootes. Draw an imaginary, arched line through the three stars
that form the handle of the big dipper. Extend the line to a
bright, orange star, Arcturus, a member of the kite-shaped
constellation Bootes.
d. Corona Borealis. To the east of the top of the kite of Bootes,
notice a circle of stars that make up the Corona Borealis, also
known as the Northern Crown.
e. Coma Berenices. Travel from Bootes toward the western horizon
to find a faint group of stars, the constellation Coma Berenices.
f. Virgo. From Arcturus in Bootes, extend an imaginary line south to
the constellation Virgo. The largest star in this group is Spica, a
very hot star that produces blue-white light. (In late summer,
Spica may be below the horizon.)
g. Libra. East of Virgo, the constellation Libra has a trapezoid
shape.
h. The summer triangle. Three bright stars, Vega, Deneb, and Altair,
form a triangle that is easily seen in the summer sky; in the
early spring sky, Altair may not be visible. Vega is a member of
the constellation Lyra, a small square of stars. The two bright
stars that make up the lower line of this square are Sheliak and
Sulafat. Deneb is a member of Cygnus, and makes up the
topmost star in the Northern Cross. Altair is the brightest star in
the constellation Aquila.
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SPRING AND SUMMER SKY OBSERVER
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i. Hercules. The constellation between the star Vega and the
constellation Bootes is Hercules. The body of this mythological
hero is outlined by four stars in a lopsided square. His arms are
two lines of stars curving south; his legs are similar lines
curving north.
Using binoculars or the low-power objective on the telescope, your
star chart, and the red-filtered flashlight, find these deep sky
objects:
a. M81 and M82. M82 is an irregular galaxy that looks like a
rounded smudge. M81 is a spiral galaxy, so it appears to be an
elongated smudge. To locate these two deep-space objects,
begin with the first star from the handle in the bowl of the big
dipper. Draw an imaginary line diagonally to Dubhe, the star in
the opposite corner. Continue out on the same line, moving
slightly north toward Polaris.
b. Double stars in the big dipper. The second (middle) star in the
handle of the big dipper is Mizar. This is actually two stars, Mizar
and Alcor. With binoculars or the telescope, you can see that
Mizar is a double star.
c. M51. Locate Alkaid in Ursa Major, then move slightly to the
south to see M51, the Whirlpool Galaxy, and a galaxy
companion, NGC 5195.
d. Virgo cluster. In the spring, find the rich fields of galaxies that
are visible northwest of Virgo.
e. M3. Find Alkaid in the big dipper. Halfway between Alkaid and
Arcturus in the constellation Bootes is a small constellation,
Canes Venatici. Slightly to the east is a group of stars known
M3.
f. M57. Locate Sheliak and Sulafat in the constellation Lyra. M57,
or the Ring Nebula, is easy to locate at low power.
g. M13. In Hercules, the M13 star cluster is located between two
western stars of the box that make up the constellation’s body.
Analysis
1.
How many stars make up the outlines of the following constellations:
a. Ursa Minor
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SPRING AND SUMMER SKY OBSERVER
2.
3.
4.
5.
5
b. Bootes
c. Hercules
Draw the shapes of two constellations that were not listed in the
procedure.
Describe the deep space object M3.
Describe the appearance M57.
Name two constellations (other than Ursa Major and Ursa Minor)
that are near Polaris.
What’s Going On?
Some stars and constellations can be seen year-round.
Polaris, or the North Star, is almost straight overhead.
Rotating around it are several circumpolar constellations,
which include Ursa Major and Ursa Minor. Stargazers can
count on seeing circumpolar constellations almost every
night that the weather permits.
Although many constellations remain in the sky for months,
some are only visible in certain seasons. In early spring, Leo
the Lion can be seen. The hindquarters of the lion are
outlined by a triangle of stars and its body extends toward
the east. The bright star Regulus is located at Leo’s heart.
Another spring constellation is Hydra, which contains the
bright star Alphard. The summer sky holds Sagittarius, which
is a mythical beast with the upper body of a man and the
lower body of a horse. The constellation looks something like
a teapot or a kettle. West of Sagittarius is Antares, a bright
red star that is 2,000 times larger than the Sun. Between
Antares and Vega is the constellation Ophiuchus, an ancient
physician who is holding a serpent. East of Ophiuchus is
Capricornus, a mythical animal with the head and front legs
of a goat and the tail of a fish.
Want to Know More?
See Our Findings.
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OUR FINDINGS
6.10 SPRING AND SUMMER SKY OBSERVER
Suggestion for class discussion: Ask students if they know how
constellations received their names. Draw the five stars of the
constellation Cepheus on the board to see if students can visualize a man
with a crown. (The square of stars represent the man’s torso; the triangle
of stars his lower body.)
Analysis
1. Answers may vary according to student skill. a. Ursa Minor, 10; b.
Bootes, six;
c. Hercules, 27
2. Answers will vary but could include the long, thin Aquarius or the arrow
head shaped constellation Capricornus.
3. a bright, globular galaxy
4. Answers will vary according to viewing conditions and student skill.
M57 appears to be a fuzzy ring of stars.
5. Answers will vary but could include Cepheus and Draco.
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SAFETY PRECAUTIONS
Review Before Starting Any Experiment
Each experiment includes special safety precautions that are
relevant to that particular project. These do not include all the basic
safety precautions that are necessary whenever you are working on
a scientific experiment. For this reason, it is absolutely necessary
that you read and remain mindful of the General Safety Precautions
that follow. Experimental science can be dangerous, and good
laboratory procedure always includes following basic safety rules.
Things can happen very quickly while you are performing an
experiment. Materials can spill, break, or even catch fire. There will
be no time after the fact to protect yourself. Always prepare for
unexpected dangers by following the basic safety guidelines during
the entire experiment, whether or not something seems dangerous
to you at a given moment.
We have been quite sparing in prescribing safety precautions for the
individual experiments. For one reason, we want you to take very
seriously every safety precaution that is printed in this book. If you
see it written here, you can be sure that it is here because it is
absolutely critical.
Read the safety precautions here and at the beginning of each
experiment before performing each lab activity. It is difficult to
remember a long set of general rules. By rereading these general
precautions every time you set up an experiment, you will be
reminding yourself that lab safety is critically important. In addition,
use your good judgment and pay close attention when performing
potentially dangerous procedures. Just because the book does not
say “Be careful with hot liquids” or “Don’t cut yourself with a knife”
does not mean that you can be careless when boiling water or using
a knife to punch holes in plastic bottles. Notes in the text are
special precautions to which you must pay special attention.
GENERAL SAFETY PRECAUTIONS
Accidents caused by carelessness, haste, insufficient knowledge, or
taking an unnecessary risk can be avoided by practicing safety
procedures and being alert while conducting experiments. Be sure to
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SAFETY PRECAUTIONS
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check the individual experiments in this book for additional safety
regulations and adult supervision requirements. If you will be
working in a lab, do not work alone. When you are working off-site,
keep in groups with a minimum of three students per groups, and
follow school rules and state legal requirements for the number of
supervisors required. Ask an adult supervisor with basic training in
first aid to carry a small first-aid kit. Make sure everyone knows
where this person will be during the experiment.
PREPARING
• Clear all surfaces before beginning experiments.
• Read the instructions before you start.
• Know the hazards of the experiments and anticipate dangers.
PROTECTING YOURSELF
• Follow the directions step by step.
• Do only one experiment at a time.
exits, fire blanket and extinguisher, master gas and
• Locate
electricity shut-offs, eyewash, and first-aid kit.
• Make sure there is adequate ventilation.
• Do not horseplay.
• Keep floor and workspace neat, clean, and dry.
• Clean up spills immediately.
• If glassware breaks, do not clean it up; ask for teacher assistance.
• Tie back long hair.
• Never eat, drink, or smoke in the laboratory or workspace.
not eat or drink any substances tested unless expressly
• Do
permitted to do so by a knowledgeable adult.
USING EQUIPMENT WITH CARE
• Set up apparatus far from the edge of the desk.
• Use knives or other sharp-pointed instruments with care.
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SAFETY PRECAUTIONS
• Pull plugs, not cords, when removing electrical plugs.
• Clean glassware before and after use.
• Check glassware for scratches, cracks, and sharp edges.
• Clean up broken glassware immediately.
• Do not use reflected sunlight to illuminate your microscope.
• Do not touch metal conductors.
alcohol-filled thermometers, not mercury-filled
• Use
thermometers.
USING CHEMICALS
• Never taste or inhale chemicals.
• Label all bottles and apparatus containing chemicals.
• Read labels carefully.
chemical contact with skin and eyes (wear safety glasses,
• Avoid
lab apron, and gloves).
• Do not touch chemical solutions.
• Wash hands before and after using solutions.
• Wipe up spills thoroughly.
HEATING SUBSTANCES
• Wear safety glasses, apron, and gloves when boiling water.
• Keep your face away from test tubes and beakers.
test tubes, beakers, and other glassware made of
• Use
Pyrex™ glass.
• Never leave apparatus unattended.
• Use safety tongs and heat-resistant gloves.
laboratory does not have heat-proof workbenches, put
• IfyouryourBunsen
burner on a heat-proof mat before lighting it.
care when lighting your Bunsen burner; light it with the
• Take
airhole closed, and use a Bunsen burner lighter in preference to
wooden matches.
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SAFETY PRECAUTIONS
4
• Turn off hot plates, Bunsen burners, and gas when you are done.
flammable substances away from flames and other sources
• Keep
of heat.
• Have a fire extinguisher on hand.
FINISHING UP
• Thoroughly clean your work area and any glassware used.
• Wash your hands.
careful not to return chemicals or contaminated reagents to
• Be
the wrong containers.
• Do not dispose of materials in the sink unless instructed to do so.
up all residues and put them in proper containers for
• Clean
disposal.
of all chemicals according to all local, state, and federal
• Dispose
laws.
BE SAFETY CONSCIOUS AT ALL TIMES!
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