Galileoscope: What Do You See? - chabotspace.org · Galileo Galilei and the Telescope ... shape...

Galileoscope: What Do You See?

Chabot Galileoscope Activity Guide

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Contents

About This Activity ................................................................................ 3

Useful Websites ................................................................................. 3

Galileo Galilei and the Telescope ............................................................. 4

Simple Refracting Telescopes ................................................................. 6

What Did Galileo Think? ........................................................................ 7

The Galileoscope .................................................................................. 8

What To Do, Step-By-Step ..................................................................... 9

Tips on sketching objects seen through telescope .................................. 9

How to write your observation journal ................................................ 10

The ―Galileo Objects‖ and How to Find Them .......................................... 11

The Moon ....................................................................................... 11

Venus ............................................................................................. 12

Jupiter ............................................................................................ 13

Saturn ............................................................................................ 14

Sky Finder Charts ............................................................................ 15

Sky Finder Chart – Summer around 10:00 PM .................................. 16

Sky Finder Chart – Autumn around 10:00 PM ................................... 17

Sky Finder Chart – Winter around 10:00 PM ..................................... 18

Sky Finder Chart – Spring around 10:00 PM ..................................... 19

Sketching Sheet ................................................................................. 20

Observing Journal Sheet ...................................................................... 21



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About This Activity

What is it? An observational exercise using a simple telescope called the

Galileoscope, created for the International Year of Astronomy 2009, which

celebrates the 400th anniversary of Galileo Galilei’s first astronomical

observations with a telescope.

Who is it for? Anyone! However, this activity was created for a classroom

of students, or individual students, of ages 10 and up.

How long does it take?

Learning about the Galileoscope and how to use it: 30 minutes Finding, observing, and sketching an object: 30-60 minutes Writing an observing journal for one observation: 15-20 minutes

What do you need?

A Galileoscope (preferably with a tripod mount, though it can be held by hand) A sketching and journaling sheet (blank copies are at the end of this guide)Error!

Bookmark not defined. A pencil A clear night sky An object finder (some information is included in this guide, starting on page 11)

Useful Websites

Here are some websites where you can find out more about Galileo,

telescopes, and the night sky:

galileo.rice.edu/galileo.html - The Galileo Project (all about Galileo)

amazing-space.stsci.edu/resources/explorations/groundup/ -

Telescopes From the Ground Up

www.fourmilab.ch/homeplanet/ - Home Planet (free desktop planetarium

software)

www.chabotspace.org/ - Chabot Space & Science Center



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Galileo Galilei and the Telescope

Galileo Galilei (gal-i-lay-o gal-i-lay-

ee) was born on February 15, 1564,

and died January 8, 1642. He lived in

Tuscany, part of modern day Italy.

Galileo was a physicist, mathematician,

astronomer, and philosopher, and an

important figure of the Scientific

Revolution.

Galileo is most famous for his work

with the telescope. The telescope was

invented in 1608 in the Netherlands,

and when Galileo heard of the new

device, he immediately made

improvements on the design and built

his own. Galileo used his telescope to

make scientific observations of objects

in the sky.

Galileo was a strong supporter of

Nicholas Copernicus’ view that the Sun,

not the Earth, is the center of the Solar System.

For these things, Galileo is sometimes called the ―Father of modern

observational astronomy.‖ Galileo’s contributions include discovering the

Moon’s craters and mountains (and attempting to measure the mountains’

heights by observing their shadows), confirming the phases of Venus,

discovering Jupiter’s four large moons, observing the peculiar shape of

Saturn (later found to be rings), and the observation and analysis of

sunspots.

Galileo’s championing of the Sun-centered model of the Solar System was

controversial, as the belief that the Sun, Moon, planets and stars all revolved

around Earth had been dominant for almost 2000 years. Galileo’s

observations with his telescope showed evidence that the Sun is at the

center and the Earth and the rest of the planets revolve around it. Galileo

was put on trial for this, and spent the rest of his life imprisoned in his own

home.

Galileo and His Telescopes



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In 2009, the International Year of Astronomy, we are celebrating the 400th

anniversary of Galileo’s first telescope observations of the sky. In honor of

his discoveries, you are invited to observe the sky and objects in it just as

Galileo did….

Above: Tuscany (black) in Modern Italy Below: Chabot, Hermosillo, and Tuscany



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Simple Refracting Telescopes

Galileo’s telescope was a very simple device, and is much like today’s

refracting telescopes. It had a small glass lens (the ―objective‖) that collects

and focuses light to form an image of a distant object, and a smaller lens

(the ―eyepiece,‖ or ―ocular lens‖) used to magnify the image.

The objective lens bends light by refraction, and its circular, curved-face

shape bends all of the light coming from an object to the same point of

focus, forming an image.

An objective lens bending and focusing an object’s light to form an image



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The rest of the telescope was a pair of

hollow tubes, one to hold the objective

and one to hold the eyepiece. One tube

slides inside the other so that the

eyepiece can be moved to focus on the

image.

What Did Galileo Think?

Step outside and take a look at the sky—

the Sun by day, and by night the Moon,

the stars, and those star-like objects that

wander slowly through the sky from

month to month, which we call planets.

Take a good look, and imagine that what

you see is all that is known about those

objects in the sky.

The Sun is bright—too bright to look at; a

blinding white disk, simple and yet

powerful.

The stars are twinkling white pinpoints, and some of the brighter ones may

even show color—blue, or red.

The planets, though you can watch them from week to week and see that

they move independently from the stars, aren’t much different from the

stars. Maybe you notice that they don’t twinkle like the stars.

And the Moon--here is something in the sky that shows us a little more

about itself than the Sun, stars, and planets. It moves the fastest, from

night to night; it changes shape throughout the month; and it has patterns

of light and dark on its face that we can see.

What would you think about the universe if all that you knew about these

objects was what you can see with your eyes?

That’s the way it was before the year 1609 CE1, before the invention of the

telescope. Imagine what the Tuscan scientist Galileo Galilei might have felt

when he became one of the first to look at these celestial objects with the

1 CE: ―Common Era‖; equivalent to ―AD‖



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magnifying power of a telescope! What did he see? How did his experience

change his thoughts about the objects he saw? How did he teach others

about his discoveries and ideas?

Whether or not you have ever looked through a telescope, or have only

observed the night sky as everyone did before its invention, there is much

for you to discover, learn, and share with others.

Enjoy your journey of discovery!

The Galileoscope

The ―Galileoscope‖ is a simple refracting telescope very similar to the one

Galileo Galilei built and used to first look at objects like the Moon, Venus,

Jupiter, and Saturn. When you look at these objects through the

Galileoscope, you will see what Galileo first saw, 400 years ago.

You may know much more about these objects because of all we have

learned over the past four centuries—but, when you look through the

Galileoscope, forget what you know. Imagine what Galileo might have

thought when he became the first to witness the wonders of the sky beyond

the power of the unaided human eye to perceive.



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What To Do, Step-By-Step

Decide which of the “Galileo objects” you will observe. You can use The Galileo Objects, and How to Find Them section on page 11, or a tool of your choice. Part of your decision depends on when these objects are visible in the sky.

Decide where you will observe from. You will need a place where you can observe safely, and which has a sky clear of trees, buildings, or hills in the area where you will find the object.

Gather your observing materials and go to your observing site. Before you begin observing, sit down and look at your chosen object with your own eyes. You don’t have to be in a hurry. This is how people saw the sky and the objects in it before the telescope--for most of human history, and long before. You might even think of something you want to write in your observing journal now, before you look through the telescope.

After you’ve enjoyed the night sky and your chosen Galileo object long enough, point your Galileoscope at it and take a look.

Don’t sketch what you see immediately; that can come later. What are your first impressions? What is the first thing you notice? Are there any surprises—things you see, or feel, that you didn’t expect? Write your first impressions in your journal.

When you’re ready, start a sketch of the object. Using a pencil, draw with as much care as you can, including as much detail as possible. The sketching sheet at the end of this guide (on page 20) has a circle for you to draw in; this represents the circular “field of view” that you see through the Galileoscope. Pay careful attention to the proportions of the object you are sketching compared to the size of the field of view circle. Draw every shape you see as accurately as you can.

Finish your observation by writing in your journal (page 21) any details about your observation and experience that you could not draw in your sketch. (Anything else about the experience that you think is important and should be recorded. Did you see any colors? Did any shapes you saw remind you of anything? Did a flying saucer fly by too quickly for you to draw?)

What do you think Galileo thought of these things he saw, but which no one else had ever seen before?

Tips on sketching objects seen through telescope

Use a pencil. With a sharp pencil you can draw fine details, and also shade in areas with different amounts of gray. You can also erase….

Looking between the telescope and your sketch, draw one detail at a time, then compare your drawing to the object. You may want to look back and forth several times to get it right.

If you are holding your telescope by hand (without a tripod or other mount), you may have to “sketch from memory”—study one detail at a time, and then put down the telescope to draw it from memory.

If you don’t have a tripod or other mount, you can steady the Galileoscope by leaning it against a fence, a wall, a box, or something like that.



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How to write your observation journal

Your observation journal is a place for you to record not only an image of

what you observe, but also your thoughts, ideas, questions, and feelings

about the observing experience. Looking through a telescope is a great

experience, and might make you ask questions you never would have

thought to ask. Your journal is a way to share your observing experience

with others, as well as to record it for yourself.

Use a blank journal and sketch sheet for each observation you make. If you

observe the same object at different times or on different dates, use a new

sheet each time. There are blank sketching and journaling sheets on pages

20 and 21 of this guide.

Each time you observe, record these

things in your journal:

Your name The date and time Your location The object being observed The weather conditions (is the sky

clear or murky? Is it warm or cold? Is it windy or calm? Is there moonlight? Is there “light pollution”?)

A careful sketch of the object, and anything surrounding it

Any questions or interesting thoughts that come to you when you look at the object (do you see any color? Is anything moving or flickering? Is there anything you see that is not possible to record in your sketch alone?)

In the blank journal sheet on page 21 you’ll notice the beginning of phrases like, “I notice…I wonder…it reminds me of….” You don’t have to answer these like questions; they are printed on the sheet to give you ideas for things to write in your journal. But write whatever you want!

Galileo's journal of Jupiter observations (notice he includes title, date, words, and

sketches)



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The “Galileo Objects” and How to Find Them

Galileo’s telescope, being one of the first, wasn’t very big or very powerful,

so he could mostly only observe the biggest and brightest objects in the sky:

the Sun, the Moon, and the planets Venus, Jupiter, and Saturn. This was a

very good start.

The Moon

The easiest of the night-time objects to find with a telescope at is the Moon.

Where you find the Moon, and what time it is up in the sky, depend on the

Moon’s phase. To find the Moon on the night (or day) that you want to

observe it, first find the date in the tables below closest to your observing

date:

Year

New Moon

First Quarter

Full Moon

Third Quarter

2011 4 Jan 12 Jan 19 Jan 26 Jan

3 Feb 11 Feb 18 Feb 24 Feb

4 Mar 12 Mar 19 Mar 26 Mar

3 Apr 11 Apr 18 Apr 25 Apr

3 May 10 May 17 May 24 May

1 Jun 9 Jun 15 Jun 23 Jun

1 Jul 8 Jul 15 Jul 23 Jul

30 Jul 6 Aug 13 Aug 21 Aug

29 Aug 4 Sep 12 Sep 20 Sep

27 Sep 4 Oct 12 Oct 20 Oct

26 Oct 2 Nov 10 Nov 18 Nov

25 Nov 2 Dec 10 Dec 18 Dec

24 Dec 31 Dec 2012 8 Jan 16 Jan

22 Jan 30 Jan 7 Feb 14 Feb

21 Feb 29 Feb 8 Mar 14 Mar

22 Mar 30 Mar 6 Apr 13 Apr

20 Apr 29 Apr 5 May 12 May

20 May 28 May 4 Jun 11 Jun

19 Jun 26 Jun 3 Jul 1 Jul

18 Jul 26 Jul 1 Aug 9 Aug

17 Aug 24 Aug 31 Aug 8 Sept

15 Sept 22 Sept 29 Sept 7 Oct

15 Oct 21 Oct 29 Oct 6 Nov

13 Nov 20 Nov 28 Nov 6 Dec



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13 Dec 19 Dec 28 Dec

2013 4 Jan

11 Jan 18 Jan 26 Jan 3 Feb

9 Feb 17 Feb 25 Feb 4 Mar

11 Mar 19 Mar 27 Mar 2 Apr

10 Apr 18 Apr 25 Apr 2 May

9 May 17 May 24 May 31 May

8 Jun 16 Jun 23 Jun 29 Jun

7 Jul 15 Jul 22 Jul 29 Jul

6 Aug 14 Aug 20 Aug 28 Aug

5 Sept 12 Sept 19 Sept 26 Sept

4 Oct 11 Oct 18 Oct 26 Oct

3 Nov 9 Nov 17 Nov 25 Nov

2 Dec 9 Dec 17 Dec 25 Dec

Then, find when the Moon rises (in the east) and sets (in the west) near

your observing date by looking up the nearest phase in this table:

Phase Rise and set times

New Moon Rises and sets with the Sun, and appears too close to the Sun to see.

First Quarter Rises around noon, sets around midnight.

Full Moon Rises around dusk, sets around dawn.

Third Quarter Rises around midnight, sets around noon.

Venus

The first rule of telling a planet from a star is that planets don’t twinkle like

stars.

Venus is the brightest planet—in fact, only the Sun and the Moon are

brighter. If Venus is in the sky at all, it is very easy to find. Its light is very

bright, white, and steady.

Venus is known as the Morning Star or the Evening Star, depending on

where it is in the sky. It is closer to the Sun than the Earth, and never stays

out all night. It either follows the Sun to the west after sunset, or leads the

way in the east before sunrise.

At other times, Venus appears too close to the Sun to be seen.



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Here is a list of the times when Venus can be found from 2009-2011:

Venus

November 2010 – March 2011 Appears as the Morning Star, visible before

dawn in the east.

December 2011 – May 2012 Appears as the Evening Star, visible after dusk

in the west.

July 2012 – December 2012 Appears as the Morning Star, visible before

dawn in the east.

June 2012 – December 2013 Appears as the Evening Star, visible after dusk

in the west.

Jupiter

Jupiter is the second brightest planet, after Venus. It looks mostly white,

but may have a slight yellow or golden color in its light.

Jupiter is farther from the Sun than the Earth, so when it becomes visible it

starts out as a morning object in the eastern sky, rising before the Sun.

Over some months, it rises earlier and earlier in the night, eventually

becoming an evening object, and finally setting in the west after dusk.

Then, it disappears in the Sun’s light for a time before reappearing in the

east.

Jupiter’s orbit around the Sun takes about 12 years. This means that

roughly each year, Jupiter can be found in a different Zodiac2 constellation.

Jupiter

2011 Found in the constellations Pisces and Aries

January Visible in the southwest after dusk, sets in the west around 10:00 PM.

February Visible in the southwest after dusk, sets in the west around 9:00 PM.

March Sets in the west not long after dusk.

July Visible in the east before sunrise.

August Rises in the east close to midnight, high in the southeast by dawn.

September Rises in the east after 9:00 PM. Up most of the night.

October Rises around 7:00 PM. Up most of the night.

November Rises around 5:00 PM. Up most of the night.

December High in the southeast after dusk. Sets by 4:00 AM.

2012 Found in the constellations Aries and Taurus

January High in the south after dusk. Sets after midnight.

February Visible in the southwest after dusk. Sets around 11:00 PM.

March Low in the southwest after dusk. Sets by 10:00 PM.

2 The 12 constellations of the Zodiac are those that the plane of the solar system (the

―ecliptic‖) passes through, as seen from Earth. The Sun and planets all appear to move

around the ecliptic.



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July Rises in the east around 2:00 AM.

August Rises in the east around midnight. Climbs high to the south by dawn.

September Rises in the east around 10:00 PM. Climbs high to the south by dawn.

October Rises in the east by 8:00 PM. Up for the rest of the night.

November Rises in the east around sunset, up for the entire night.

December Climbs high in the south by midnight. Up for the entire night.

2013 Found in the constellations Taurus and Gemini

January High in the south after dusk, sets in the west around 4:00 AM.

February High in the south after dusk, sets in the west around 2:00 AM.

March High in the southwest after dusk, sets in the west just after midnight.

April Visible in the southwest after dusk, sets by 11:00 PM.

May Visible in the southwest after dusk, sets after 9:00 PM.

August Rises in the east around 2:00 AM, up for the rest of the night.

September Rises in the east after midnight, up the rest of the night.

October Rises in the east by 11:00 PM, up for the rest of the night.

November Rises in the east by 9:00 PM, climbing high in the south by dawn.

December Rises in the east after sunset, up for the rest of the night.

Saturn

Saturn is somewhat bright, and whitish-yellow or whitish-gold—much like a

less-bright version of Jupiter.

Saturn

2011 Found in the constellation Virgo

January Rises in the east around midnight and climbs high in the south by

dawn.

February Rises in the east around 10:00 PM and climbs high in the south by

4:00 AM.

March Rises in the east around 8:00 PM, climbs high in the south by 2:00

AM, and moves southwest by dawn.

April Visible in the east after dusk, climbs high in the south by midnight,

and sets in the west after 5:00 PM.

May Visible in the southeast after dusk, climbs high in the south around

9:00 PM, and sets in the west after 3:00 PM.

June Visible in the south after dusk, then moves west and sets after 1:00

AM.

July Visible in the southwest after dusk and sets before midnight.

August Visible in the southwest after dusk and sets after 9:00 PM.

December Rises in the east before dawn.

2012 Found in the constellations Virgo

January Rises in the east around 1:00 AM, up the rest of the night.

February Rises in the east by 11:00 PM, up the rest of the night.

March Rises in the east by 9:00 PM, up for the rest of the night.

April Rises by 7:00 PM, high in the south around midnight, and sets by

6:00 AM.



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May Visible in the southwest after dusk, directly south around 10:00 PM, and sets by 4:00 AM.

June Visible high in the south after dusk, sets by 2:00 AM.

July Visible high in the south after dusk, sets by midnight.

August Visible high in the southwest after dusk, sets by 10:00 PM.

2013 Found in the constellation Libra

January Rises in the east around 2:00 AM, high in the south by dawn.

February Rises in the east around midnight, high in the south by dawn.

March Rises in the east around 10:00 PM, visible in the southwest by dawn.

April Rises in the east by 8:00 PM, high in the south by midnight.

May Visible in the southeast after dusk, high in the south by midnight,

sets after 4:00 AM.

June High in the south by 9:00 PM, sets after 2:00 AM.

July High in the south after dusk, sets after midnight.

August Visible in the southwest after dusk, sets after 10:00 PM.

Sky Finder Charts

On the next four pages you will find maps of the sky as it appears around

10:00 PM during the four seasons. Choose the map for the season you are

in, and hold it overhead with the N, E, S, and W lined up with the actual

north, east, south, and west direction on your horizon. The black circle on

the map represents the horizon. Then, compare the stars on the map with

the stars in the sky.

The names and stick-figures of the constellations and the names of some of

the brightest stars are shown. Also, the ecliptic—the path on which the Sun

and planets can be located—is shown.



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Sky Finder Chart – Summer around 10:00 PM



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Sky Finder Chart – Autumn around 10:00 PM



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Sky Finder Chart – Winter around 10:00 PM



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Sky Finder Chart – Spring around 10:00 PM



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Sketching Sheet



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Observing Journal Sheet

Galileoscope: What Do You See? - chabotspace.org · Galileo Galilei and the Telescope ... shape...

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