Hubble Space Telescope
Making Your Observations
First airs live, March 14, 1996, 13:00-14:00 Eastern
"Making YOUR Observations" will climax with a live "First Look" at the
original astronomical data acquired as a result of the Passport to Knowledge
observations. Planet Advocates Heidi Hammel, Marc Buie and participating
K-12 students will see, at exactly the same moment, what we've collectively
discovered about Neptune and Pluto, during a live uplink from the Space
Telescope Science Institute, in Baltimore, Maryland (STScI). ("First Look"
is what astronomers call their initial glimpse of new data: during the
comet Shoemaker-Levy 9 collision with Jupiter, "First Look" was welcomed
with whoops of delight and celebratory toasts, as we'll see during this
program.) There'll be another, equally unique "First Look" as for the
first time ever live cameras are welcomed into the Space Telescope
Operations Control Center at NASA's Goddard's Space Flight Center. Though
there's no live camera currently up in orbit to show us HST from outside,
we'll see exactly where HST is at that precise moment, and exactly what
HST is seeing. Via our live cameras, students will come as close, virtually,
to HST as any human on Earth can ever be. Students will look over controllers'
shoulders and see what happens as the telescope slews to acquire new guide
stars, or "dumps" its data from the on- board tape recorder. If there
is a spacecraft "Health and Safety" emergency, however, we will be unceremoniously
booted out of the Mission Operations Room!
Videotaped sequences will show the wide variety of people it takes to
operate HST, from astronomers and astronauts, to engineers, computer programmers,
communications specialists, mathematicians, graphic artists, technical
writers... secretaries. Footage from across America and around the world
will show the diverse places, far from STScI and GSFC, where HST work
is performed, and the processes which are involved. Students will see
what HST has contributed to our understanding of the solar system, and
will appreciate that while spacecraft missions have returned stunning,
high resolution images of nearly all our local planets (except Pluto),
HST provides ongoing coverage, functioning as a kind of "interplanetary
weather satellite" for our cosmic neighborhood.
Heidi Hammel and Marc Buie will review what we know about Neptune and
Pluto, what they hope the new images might reveal, and describe the hard
work they'll be facing in the coming five weeks, to prepare the brand-new
data for the April 23rd telecast. Students will find out how they also
can work on the data, using custom software and lessons plans provided
over the Internet by Passport to Knowledge and others. "Mrs. Jupiter,"
Planet Advocate Reta Beebe, shares images from the RbonusS orbit observing
Jupiter which she's contributing to the project, and we see how researchers
use the huge STScI data archive to compare and contrast past pictures
to help make sense of new information.
The program will also provide an e-mail address where questions can
be sent during the live broadcast, providing information about how to
participate using e-mail or the World Wide Web. Students will meet some
of the men and women on the Hubble team who've volunteered to write Field
Journals and who'll be responding to student questions on-line as
part of Researcher Q&A.
In addition to live uplinks from STScI and GSFC, students from Washington
state will participate via satellite and interactive video: some of them
played a role in the "Great Planet Debate" and will now witness results
of the decision they helped make. In another first for Passport to
Knowledge, students at the European Space Agency's ECF (European Coordinating
Facility) in Garching, near Munich, Germany, will interact via videoconferencing.
(ESA built the FOC, or Faint Object Camera, which will be used to image
Pluto.) We expect e-mail input directly from schools in Brazil, some in
Manaus in the Amazon rainforest, who will be watching the programs live
via USIA's Worldnet.
Tony Roman, Program Coordinator, STScI
My job is to help astronomers specify all the technical details necessary
to conduct observations with the Hubble Space Telescope... then to take
that and process it so that the observation eventually becomes something
that the computers on board the telescope can understand and perform. Sometimes
when you work with these difficult observations it can be a significant
challenge to get them to work, and sometimes when you are caught up in all
these details, you kind of forget that what you're really doing is working
on putting together observations for one of the most powerful observatories
the human race has ever built... when the data comes back at last I feel
pretty excited and pretty proud to have been a part of that.
I was interested in astronomy since I was a small child, I guess, and
I studied physics in college, and mathematics. Those are very important
backgrounds for astronomyI I became interested in astronomy through my
father, an engineer who worked on the Pioneer and Viking missions. Even
though he wasn't an astronomer, he was working on those missions. And
even though, at the time, I didn't really understand what he did, just
the fact that that's what he was doing got me interested. Also, a more
specific example, was that Carl Sagan had a television show on PBS called
Cosmos that I found very inspirational.
Activity 2A: Using a Concave Mirror to focus Radiation
Students will demonstrate the ability to explain how different forms
of electromagnetic radiation can be focused using a concave mirror, and
how HST's mirror functions.
Ask students why we use telescopes to study the universe. Answers may
center on the power of various telescopes and their ability to show distant
objects close up. Tell students that while telescopes do give us visually
magnified images of distant objects, this isn't really their main function.
(General background on the electromagnetic spectrum, as well as several
hands-on activities, may be found in the Live from the Stratosphere
Teacher's Guide, or in NASA's Space Based Astronomy, co-packaged with
this LHST Guide.)
Explain that astronomers learn about objects in space by studying and analyzing
the radiation that comes to us from these objects. The more radiation an
astronomer can collect from an object, the more he or she can learn about
that object because radiation is the carrier of information. So, really,
astronomers are not as interested in the power of a telescope as in how
much visible light and other radiation the telescope can collect and concencentrate
for study. This amount is usually far greater than can be achieved with
the human eye alone. In this Actvity, students will be able to calculate
how much more radiation the HST can concentrate for study than can their
own unaided eyes. They will see how a concave mirror, like that in the HST,
focuses or concentrates radiation.
Materials For use in demonstrations by the teacher:
- concave mirror (such as is used for shaving or applying make-up, or
as can be purchased from a supply company e.g., Edmund Scientific Catalog
#S52,016 [$26.00] or #S42,427 [$9.95]).
- candle or other small, bright light source
- thermometer and/or the heat-sensitive paper co-packaged with this
- source of UltraViolet radiation (a UV lamp such as Edmund Scientific
Catalog # S35,485 [$36.95] or #S34,501 [$32.95]) (Middle and elementary
schools may find they can borrow this from their high school.)
- piece of tracing paper or wax paper
- electric space heater
- small jar of fluorescent luminous paint (such as Edmund Scientific
Catalog #S31,806 [$10.95] or as is available in some art supply stores.)
or the UV-sensitive beads co-packaged with this Guide
For each team of students
- cup of paper circles (the stuff you usually throw away after making
holes with a 3 ring binder punch)
- a circle of dark construction paper, 6 inches in diameter
Sketch on the chalkboard how a concave mirror focuses radiation using
a simple ray tracing diagram, as shown above. Explain that the HST's primary
mirror is curved like the drawing on the board (see cutaway HST diagram
to left), and like the demonstration mirror you have acquired for this
Proceed with one or more of the demonstrations on the following page.
Activities 2A and 2B
1 Focusing Visible Light
Darken the classroom as much as possible. Light the candle or other small,
bright source of light and place it several feet away from the mirror. Hold
the mirror in one hand and the piece of tracing or wax paper in the other.
Adjust the position of the mirror and paper until the candle flame or other
light source is focused on the paper for the class to see.
2 Focusing Infrared Radiation
For this demonstration, the classroom can be fully lit. Explain that concave
mirrors such as this one, and that on the HST, are also capable of focusing
infrared (IR or heat) radiation from objects on Earth and in space, just
as they do visible light. At this point produce a safe and handy source
of infrared radiation such as an electric heater. Since infrared radiation
is invisible to the unaided eye, challenge the students to suggest ways
that you can know whether or not the mirror is indeed focusing this radiation
from the heater. If a student suggests using the thermometer or heat-sensitive
paper, let them go ahead and do the demo for you! If not, produce an answer
by holding up the thermometer. Note the general temperature in the room.
Then place the heater several feet away from the mirror at the same spot
where you had placed the candle in the last demonstration and turn the
heater on. After a few minutes, hold the mirror in one hand and the thermometer
in the other. Place the thermometer at the same point where you placed
the paper in the last demonstration. (Hint: as preparation you may want
to have a C-clamp or other stand so that you can precisely mark the place
to hold your detector in this and the following demonstration.) Have one
or two students read off the temperature. It will rise as the mirror focuses
the heater's otherwise invisible infrared radiation at this point in space.
To parallel the first demonstration more precisely, use the heat-sensitive
paper: it will turn white where the mirror focuses the IR radiation, and
then turn colored once more when removed.
3. Focusing Ultraviolet Radiation Explain that concave mirrors
such as the one on the HST are also capable of focusing ultraviolet radiation
from objects on Earth and in space. Hold up the ultraviolet lamp for the
class to see, plus the UV-sensitive beads or the jar of fluorescent luminescent
paint and a small piece of plain paper. Explain that the paint and/or
beads contain special chemicals that glow or change color when exposed
to ultraviolet radiation. Apply the paint to the paper.
This time, darken the classroom as much as possible, if you use the
paint rather than the beads. Turn on the UV lamp and place it in the same
position as the candle and heater in the previous demonstrations. Hold
the mirror in one hand and place the beads or painted piece of paper at
the same place where you placed the tracing or wax paper. Students will
begin to observe the beads change color or the paint glow from the concentrated
UV radiation. Removing the beads or paper from the focus of the mirror
will cause the glow to become reduced or to cease.
Hubble: A Very Big Eye in the Sky
Students will first estimate and then calculate the amount of light which
can be gathered by HST's main mirror, and then compare and contrast this
with the light-gathering power of the human eye.
Procedure Divide the students into teams. Give each team the
disk of dark paper 6 inches in diameter and a cup with the white paper
circles made by a 3 ring hole punch. Explain that the white circles are
about the size of the pupil of the eye. Ask the students to spread the
white circles out onto the dark circle and estimate how many white circles
cover the dark circle, with no overlap of white circles but as little
dark material as possible showing through. Tell them to make their best
estimate. When the team are through, write down their answers and ask
the class to compute the average. Explain that the HST's main mirror has
about 248 times more area than do their 6 inch paper disks. Have them
multiply the average they calculated by 248 for their answer.
Finally have them calculate the answer directly by using the formula
for the area of a circle:
A = p*r*r, where p = 3.1416 and r = the radius of the circle. (The relevant
HST dimensions appear on the student worksheet.)
Discuss the reason for different answers to the above question using
the two techniques. Which is more accurate? Also have students research
and discuss what types of information might be learned about the planets
by studying them in the infrared and the ultraviolet as well as in visible
With our eyes alone, we can only see things down to a certain level
of faintness at night or in a darkened room. We are limited by the amount
of light that can pass through the pupils of our eyes which rarely widen
to more than 0.25 inches across.
Telescopes allow us to see fainter objects because a telescope takes
all the light that falls on its main lens or mirror and focuses, or concentrates,
it down into a narrow beam that can usually pass through the pupil of
the eye. Thus if an astronomer looks out at night with a telescope like
the HST which has a mirror some 94.5 inches across, he or she is looking
out on the universe with the equivalent of eyes that are 94.5 inches across!
No wonder we can see more with telescopes.
How much bigger is the HST's main mirror than the human eye? Well, it's
94.5 inches divided by 0.25 inches, or 378 times the diameter of your
pupil! But the true ability of the eye or a telescope to gather light
depends on the area of its lens or mirror, not its diameter.
So how much more light does the HST focus than your eye? Let's use two
methods to find out.
Method #1: Estimation Using a Physical Model
Your teacher will distribute dark circles and cups with small white circles,
which are about the size of the pupil of your eye. Carefully spread out
the small white circles on the dark circle. How many does it take to completely
cover the dark circle? Try to have as little overlap and as little dark
material showing through as possible.
Write your estimate here.
Write the average estimate of all the teams in your class here.
The HST's main mirror has an area about 248 times greater than your
dark circle. So how many little white circles would it take to cover the
entire main mirror of the HST? This is an estimate of how much more light
falls on the HST than on your pupil, and so approximately how much more
light the HST can focus.
Method #2: Direct Calculation
The amount of light a mirror or lens focuses depends upon its area. The
area of a circle is given by the formula: A = pr2, where p = 3.1416 and
r is the radius of the lens or mirror, that is its diameter divided by 2.
How much more light does the HST focus than the lens in your eye? That's
the same as asking how much greater is the area of the HST's main mirror
than the area of the pupil of your eye. First, calculate the area of the
HST's main mirror (All the information you need is contained in the Introduction
to this Activity, at the top of the page.) Write your answer here _________.
Next, calculate the area of the pupil of your eye. Write your answer
here. Finally, calculate how many times bigger the first area is than
the second. Write your answer here ________.
Compare your answers using method #1 and #2. Which do you think is more
Activity 2C: Observing "Moving Targets" with the
Students will demonstrate the ability to plan Hubble observations by
plotting planetary positions at 3 specific dates on a sky-chart, determining
a safety zone for HST, and verifying the accuracy of their results.
Point out to the students that most of the objects that astronomers
look at in the sky are very faint and that, accordingly, most of the HST's
instruments are very, very sensitive to light. Ask them to think about
objects which HST cannot look at because they are so bright that they
would blind and ruin the instruments. (The obvious answer is the Sun -
but in fact the moon is also too bright). Tell them that for safety reasons
the HST is usually not pointed within about 45 degrees of the Sun. (Note:
A fist held at arm's length is about 10 degrees across.)
Tell the students that in this activity they are going to serve in the
important role of Mission Planners for the HST (STScI calls such specialists
"Program Coordinators'" one of whom is Tony Roman, who'll appear on camera
in Program 2, and whose comments may be found in this Guide.) For three
different dates, students will determine which explain to the students
that the planets and the Sun appear to move continuously relative to the
"fixed" stars and so their changing positions need to be constantly tracked.
Even though the planets of our solar system are close by, and relatively
bright, they're literally "moving targets" and sometimes quite difficult
Materials (for each Mission Planning Team)
- copy of HST "Zone of Solar Avoidance Disk" (Figure)
- Coordinate Tables for Sun and planets for 3 dates (Below)
- 9 different colored marking pens
- scissors, pins or pushpins
- 3 copies of Star Chart (figure)
Divide the students into Mission Planner Teams. Distribute materials to
each Team. Ask them to make a color key for their own reference, and assign
a different colored making pen to the Sun and each of the eight planets
other than Earth. Point out the dates on the three separate Coordinate
Tables and have them mark each of their three Sky Charts with one of the
Illustrate how to plot a position on the first Sky Chart (March 14,
1996) using the Sun as an example. Have them mark their March 14 , 1996
chart making a small dot with the appropriate colored marking pen for
the Sun. Then have them continue to plot and mark the positions of the
planets on the same Chart. Have them proceed to the other two Charts and
changed from one chart to the next.
Next, ask them to cut out their HST "Zone of Solar Avoidance" disk.
Explain that this disk is designed to help them determine which planets
are too close to the Sun to be safely observed with the HST. Make as many
copies (or transparencies) as needed and give one to each team. Then,
for each of the three Sky Charts, have the students carefully pin the
center of the disk on the Sun. All planets lying within the disk are too
close to the Sun to observe safely. For each Chart, have them complete
the list on their Worksheets of which planets are safe, and which are
not safe, to observe for the date of the Chart.
Ask students to research thoroughly the changing positions of planets
to see if there's a planet which can never be observed with the HST.
In this Activity you and your team are going to become Mission Planners
for the Hubble Space Telescope. Astronomers cannot just look at any planet
with the HST, anytime they wish. This is because planets change position
in the sky relative to the Sun, and the HST's instruments are so sensitive
they are usually not pointed within about 45 degrees of the Sun. Sometimes,
the planets wander too close to be observed safely. Your job will be to
figure out for the astronomers, for three different dates, which planets
can and cannot be observed with the HST.
Your teacher will pass out Sky Maps and Tables of positions for the
Sun and the planets on three different dates. As instructed, plot the
position of all these celestial objects on the appropriate Star Charts.
Use the HST Zone of Solar Avoidance disk to determine which planets are
safe to view and which are not for each of the dates in question. Once
you have plotted all your data, fill the appropriate spaces in the Table
below with the words SAFE or UNSAFE
PLANET March 14, 1996 January 15, 1997 March 14, 1997
Then answer the following questions.
1. What can you say about the position of the Sun on March 14, 1996 and
March 14, 1997. Why?
2. Which two planets appear close to the Sun on all three dates? Why do
you think so?
3. The dashed line in your Charts shows the path of the Sun among the
stars as seen from Earth (known as the "ecliptic"). All the planets (except
Pluto) lie very close to this line. Why? (Hint: It has to do with the
shape of the solar system)
TABLE 1 March 14, 1996
OBJECT R.A. Dec.
Sun 23.6 hrs. 2.5 deg.
Mercury 22.9 hrs -9.5 deg
Venus 2.4 hrs. 16.2 deg
Mars 23.5 hrs -4.2 deg
Jupiter 19.0 hrs -22.6 deg
Saturn 23.9 hrs -3.0 deg
Uranus 20.4 hrs -19.9 deg
Neptune 20.0 hrs -20.3 deg
Pluto 16.3 hrs -7.8 deg
TABLE 2 January 15, 1997
OBJECT R.A. Dec.
Sun 19.9 hrs -21.0 deg
Mercury 18.3 hrs -20.9 deg
Venus 18.5 hrs -23.1 deg
Mars 12.3 hrs 1.3 deg
Jupiter 20.1 hrs -20.8 deg
Saturn 00.2 hrs -1.3 deg
Uranus 20.4 hrs -19.8 deg
Neptune 20.0 hrs -20.3 deg
Pluto 16.3 hrs -8.7 deg
TABLE 3 March 14, 1997
OBJECT R.A. Dec.
Sun 23.6 hrs -2.5 deg
Mercury 23.8 hrs -2.9 deg
Venus 23.3 hrs -5.9 deg
Mars 12.0 hrs 4.2 deg
Jupiter 20.9 hrs -17.8 deg
Saturn 00.5 hrs 1.2 deg
Uranus 20.6 hrs -19.0 deg
Neptune 20.1 hrs -19.9 deg
Pluto 16.4 hrs 8.7 deg
Activity 2D: Bouncing Data around the World
This activity is from the original
Satellite Dataflow lesson plan, with many hyperlinks and a video, created
by Dennis Biroscak, Satellite Operations Manager,
Center for Extreme Ultraviolet Astrophysics, University of California
at Berkeley, and by Marlene
Wilson, a fourth grade teacher at
Fruitvale School, Oakland, California, as part of EUVE's satellite operations
class for teachers taught by
Dr.Isabel Hawkins and adapted with their permission for Hubble Space
Students will demonstrate the communications path between a distant planet
and an observer on Earth, with data transmitted via HST, communications
satellites and ground stations.
Ask students to relate how a letter, sent from far away, gets to their
house. Have them brainstorm a list of places the letter may have passed
through - including the Internet - what kinds of vehicles may have been
used to carry it, how long it took to travel to its destination, etc.
Explain that scientists need to send instructions up to HST as it orbits
the Earth as well as receive data back from it. This activity will help
students better understand the communications path between a scientist
such as our Planet Advocates, and they themselves as LHST "virtual co-investigators,"
and the Hubble Space Telescope, showing how data are sent and received.
A minimum of eight students is necessary for this activity
- one 6" or 8" ball (slightly deflated)
- tennis ball (optional)
- Set of 8 signs mounted on cardboard and string that students can wear
around their necks. Signs should read: Planet (Neptune or Pluto?), HST,
TDRS, (Tracking & Data Relay Satellite) White Sands, DOMSAT, (domestic
satellite) Goddard (or GSFC), STScI, P.I. (Principal Investigator)
- clear space enough for the demo (20' x 20' at least)-a gym is ideal.
Everyone must be free to move-no tables or chairs in the way.
- Picture of the HST satellite
Show students the overhead transparency of the HST satellite data flow.
Explain the diagram, following the data path as shown. Explain that the
HST receives, stores, and later relays data that is detected by the telescope.
Explain that TDRS is operated by NASA and communicates with the ground
station at White Sands, New Mexico. TDRS is in a geosynchronous orbit,
meaning it is synchronized with the Earth's rotation ("geo" meaning Earth).
TDRS is approximately 26,000 miles from the center of the Earth. All geosynchronous
satellites are positioned at this distance. Their period of revolution
is the same as the time it takes for the Earth to rotate once around its
axis. (NASA actually operates two geostationary satellites for HST, TDRS
East and TDRS West, but only one TDRS communicates with HST at a time.)
Four students are placed back to back in the center of the room forming
a circle that will represent the Earth. (This is done for ease of the
demonstration although in reality, all of the ground stations are on the
continental United States and therefore the satellites would actually
only send signals to a portion of the Earth rather than to the whole globe.)
Each of the four students is given a sign to wear-in consecutive order
from left to right:
P.I., STScI, Goddard, White Sands. This may sound complex, but just look
at the diagram looking down on
Earth's north pole locations and with an arrow specifying rotation and
all will become clear!
- TDRS: one student is placed at the edge of the room exactly opposite
White Sands, NM, and wears the sign TDRS.
- DOMSAT: another student wearing DOMSAT is placed just as far away
from the Earth as TDRS, but is positioned between White Sands and Goddard.
Explain that DOMSAT is another geosynchronous satellite used by NASA
which also relays TV programs and other communications. At this point,
you could start the Earth rotating SLOWLY and let the geosynchronous
satellites move sideways to try to keep up with the Earth. They have
to remain over the same spot on the Earth. You could also wait until
everyone gets assigned a position before you start the rotation.
- HST: another student is given the HST sign to wear. Explain that HST
is only 380 miles above the Earth. Position this student very close
to the Earth. HST travels around the Earth approximately 15 times for
every once that the Earth turns (15 times per day), so it moves around
the Earth much faster than the rate at which the Earth rotates.
- PLANET: from a corner of the room or anywhere well outside of
the outer satellites, a student is positioned with the PLANET sign.
The student is given the small, slightly-deflated ball that will
representing star light. For the purposes of this demonstration
the PLANET does not move, so the student stands still.
The path of data from the planet to the P.I. is as follows: Planet,
HST, TDRS, White Sands, DOMSAT, Goddard, STScI, P.I.
Motion in Space
Make sure students understand the difference between rotation and revolution.
Within the revolution category are two subcategories, geosynchronous (or
geostationary) revolution and non-geosynchronous revolution. For this
demonstration, the only satellite that is non- geosynchronous is the HST.
At this point, you may want to do a small "sub-demo" by having one student
stand at the center of the room representing Earth, who will then rotate
while one person on the outside (a satellite) follows the face of the
"Earth." Students will clearly see that the Earth needs to rotate very
slowly to allow time for the satellite to follow (around the circumference
of the room). Then start the motion in space with everyone except the
PLANET as described above. Now call out the path as the students throw
the ball. Have them call out who they are as the ball is caught by each.
- The Planet throws the ball (planetary image) to HST.
- HST sends the ball to TDRS.
- TDRS sends the ball to White Sands.
- White Sands sends the ball up to DOMSAT located between White Sands
- DOMSAT sends the ball to Goddard.
- Goddard "hands" the ball to STScI (since the data are transported
through ground-based phone lines at this point).
- Finally, the ball (planetary image) is handed from STScI to the P.I.
(Surprisingly enough, this is usually done via FEDEX!)
Variations: Data Drop-out
When someone drops the ball, it can be considered data "drop-out" and
the ball goes back to the planet again. Explain that a data drop-out can
occur at any point in the communication path.
Commanding the HST
Another ball (tennis ball or other colored ball) could be used to represent
a command from the P.I. to HST. The path of the command is the same but
in the opposite direction (P.I., STScI, Goddard, DOMSAT, White Sands, TDRS
and HST). For more of a challenge, this can be done simultaneously with
the incoming data from the planet, as in real life. After the physical demonstration
is complete, have students diagram the activity, labeling all the locations,
and using arrows to indicate the flow of data, as if from a perspective
out in space. [Younger students might be given a copy of the diagram used
to introduce the activity (remove arrows and labels before copying) on which
to draw the path.] Illustrations and diagrams should be added to their HST
portfolios. Your students might also enjoy working collaboratively to produce
a hall display or large mural showing the datapath.
Calculate the total time it takes light to travel the satellite pathway
from our target planets via HST to Goddard. (Hint: remember the formula:
Distance = Speed x Time.) What else do you need to know? Speed of Light
= 186,000 miles per second. What about the number of miles between Earth,
the various satellites, and the planets? The necessary information is
all provided above and in Activity 1C-but students will have to apply
some geometry to figure things out!
The original Satellite Dataflow activity, developed to help explain
the operations of the Extreme UltraViolet Explorer satellite (EUVE) provided
the following Math problem. (To make this applicable to HST, substitute
HST for EUVE, and use 380 miles for the distance from the surface of the
You can also calculate the approximate speed of the EUVE given:
Remember, speed equals distance traveled divided by the time it takes to
travel the distance. For example, and as a BIG hint, since the circumference
of the Earth is approximately 25,000 miles (distance), divide this by 24
hours for one rotation (time it takes to travel the distance), and you will
have the speed of the rotation of the Earth (just over 1000 mph).
- the diameter of the Earth=7972.5 (or 8000) miles
- the position of EUVE is 315 miles beyond the surface of the Earth
- "pi" (3.1417) x D = circumference
- EUVE makes approximately 15 revolutions once every 24 hours
Watch on-line and on camera for more Challenge Questions.
Hubble as a Weather Satellite for Our Solar System
Earth has been called an "incredible weather machine." Orbiting satellites
hourly scan the planet from pole to pole, tracking storms, recording temperatures
and moisture levels, and helping meteorologists make better weather forecasts.
Can you think of a satellite that's regularly used to study weather on other
planets? It's the Hubble Space Telescope, often doing as much meteorology
as astronomy-scanning our celestial neighbors and revealing amazing worlds
of weather clear across the solar system. Mars has a thin atmosphere of
carbon dioxide that keeps the planet drier than the Sahara and far colder,
on average, than Antarctica. Hubble has shown us that the planet's temperature
is now, on average, some 20 degrees less than that recorded by the Viking
spacecraft in the 1970s, a significant and puzzling change.
At the edge of the solar system, orbits tiny Pluto. Like Neptune's moon,
Triton, Pluto may have a thin nitrogen atmosphere that sometimes propels
frosts and fogs across its icy landscape, and at other times freezes in
place as Pluto's "seasons" change. Only closer study will reveal Pluto's
climate and weather. Between Mars and Pluto are Jupiter, Saturn, Uranus
and Neptune, giant worlds whose faces are but the tops of enormous, turbulent
atmospheres, thousands of miles deep. Here weather is driven not by the
Sun but by heat rising from within. Soaring air currents couple with the
planets' rapid rotation rates to produce jet streams that can race at
over 1,000 miles per hour and produce storms larger than the entire Earth.
When astronomers speak about the atmospheres of the other planets, you'll
hear them talk of winds, temperatures and atmospheric pressures. Much
of the vocabulary of interplanetary weather will sound familiar to you
and your students from tv weather reports, but the scale will be very
different. After all, we're talking about other worlds, giant, strange
and fascinating. Using the Hubble Space Telescope to study our planetary
neighbors, scientists are studying weather on a cosmic scale, with many
more examples than were available before the Space Age. In the process,
they are trying not only to understand weather on each individual planet
but also the similarities and differences between these worlds, and what
they mean for Earth, now and in the future.
Activity 2E: Pictures from Outer Space
Students will simulate the interrelated processes by which spacecraft
computers encode pictures of a planet, and computers on Earth later decode
digitized data and transform it back into an image of the planet.
Ask students to think about the last time they or one of their family
members took pictures with their still camera. Ask them how they think
the image of the real world got from inside their camera into their hands
as finished prints. (The answer is, of course, a physical thing called
film which, after being exposed to light, is removed from the camera,
chemically processed at the photo shop and returned as prints or slides).
Ask them how they think we get pictures from the HST and other spacecraft?
Early satellites did indeed parachute film packs back to Earth, but that's
not the way it's done today. And astronauts aren't always popping up to
change the film, so how does it work?
Figures for this section.
Instructions on how to make/use the
Diagram of data strip placement.
Materials (for each team)
- photocopy of the grid
- set of 4 paper sheets of differing shades of black to white (black,
dark gray, light gray, white)
- glue, scissors, four paper cups (to hold sets of paper squares)
Have the students examine a TV or computer screen with a magnifying
glass. Ask them to describe what they see. They'll note the picture is
actually made up of little dots (called pixels, or picture elements.)
Explain that the HST and other spacecraft actually send images to Earth
by radio as a long string of numbers which tell the location and brightness
of each pixel in the image. Then computers put all the pixels together
like a great cosmic jigsaw puzzle. Explain that in this Activity, they
are going to take the place of NASA computers and convert a string of
coded data from a spacecraft back into the image of an actual object in
Begin by dividing the class up into ten Data Analysis Teams (and since this
is a space-related project, you can call them DAT's. All space agencies
love acronyms.) Give each DAT a copy of one of the coded lists of numbers
(their "data stream") from your Master Code List. Also provide a copy of
- their grid provides the framework for one portion, strip or slice
of the picture to be deciphered from space
- the numbers in their data stream represent information on the brightness
of the 1120 image pixels that they will be responsible for putting in
- the order of the pixels in their data stream is a clue to the order
in which their pixels are to be arranged in their portion of the final
Instruct them to place the grid horizontally on their desk tops (with
the "L" mark on the left) and begin to encode the image by placing the
first number in their data stream in the uppermost left box in their image
grid. (Here they are doing, in a greatly simplified way, what the CCD
detectors on board a spacecraft do when they observe a target.) Then place
the second number in the data stream in the box on the same line immediately
to the right, the third number in the next box, etc. When the first line
is complete, tell them to begin filling in the second line of the grid,
again from left to right, and continuing until their entire grid is filled
in. Then one member of the team should re-read the numbers as the others
check for accuracy.
When all teams have completed this task, pass out a set of paper sheets
to each team. Explain that the shades of brightness and darkness correspond
to the numbers sent down by the spacecraft with 0 representing pure white,
1 light gray, 2 dark gray and 3 representing black. Tell them to carefully
cut the pieces of paper into small squares each the size of one of the
grid boxes and to group each different color into a different pile. (An
alternative is to use a paper-cutter, carefully, to mass produce squares
in advance, then distribute them in paper cups) Have students glue an
appropriately shaded square over each correspondingly-numbered grid box.
Be sure to have one member of the DAT time how long the process takes
to code their grids. When all the DATs are finished, assemble all the
pieces of the image to create the full image (as shown below left) on
a larger piece of paper or card. As the image comes together, challenge
them to identify it, giving clues as you go. When completed, tell them
the significance of Jupiter's Great Red Spot, and show them the actual
image from Voyager 2 for comparison (to be seen in Program 1, "The Great
Planet Debate" and on the HST lithographs co-packaged with the Guide).
Relate the coarsely-detailed (or "low resolution") image the students
assembled to an actual image from the HST, as on the enclosed lithographs.
These images clearly have more detail because they contain many more pixels
in the same space and incorporate many more shades of gray between white
and black. In short, it contains much more (picture and computer) information.
(See Activity 3A page 30 for how black and white data becomes a color
image.) Have the students compare the number of pixels and shades of gray
in their image and one from the HST, using the information given in their
Worksheets. Finally, ask them to calculate how much longer it would have
taken them to assemble the real image at the rate they worked.
How HST's Instruments Share the Telescope's Focal Plane & Incoming
From pixels to pictures
The Hubble Space Telescope and other spacecraft, including weather satellites,
take pictures using video technology and devices known as charge coupled
devices, or CCDs for short. Like a picture on a TV set or computer screen,
each image is made up of thousands of tiny dots or picture elements ("pixels").
The pictures are not sent down to the ground as hard copy. Instead, the
photons of light reflected off an object are collected by the sensitive
CCDs, and recorded and analyzed pixel by pixel. Then, the information
on the location of each pixel within the picture and the brightness of
that particular pixel is radioed down to Earth. Computers convert this
information back into light and dark spots and place these pixels in their
correct positions, so that a complete picture is re-constituted by computer.
Prints and slides can then be made. This is the process you and your students
will see happening for images of Jupiter, Neptune and Pluto during the
videos, and you'll be able to follow the Planet Advocates' image processing
work on-line, during the hectic weeks between the live broadcasts.
Another key thing to appreciate is that the HST and other spacecraft
take their images in black and white. Yet we see beautiful spacecraft
images in full color, such as the M-16/Eagle Nebula picture co-packaged
with this Guide. How is this possible? To make a color image of an object,
the spacecraft takes several black and white images, each through a different
colored filter. By carefully examining how bright different parts of the
object look through the different filters, scientists using computers
can figure out the true appearance of the object, and so re-create a realistic
Announcing YOUR Results
Pictures from Outer Space
First airs live April 23, 1996, 13:00-14:00 Eastern
This program will take the form of a highly interactive scientific symposium,
oriented to students, announcing the first results achieved by Live from
the Hubble Space Telescope. A live student audience of over one hundred
will join Marc Buie and Heidi Hammel in STScI's main auditorium in Baltimore,
with e-mail and CuSeeMe input from other students around the nation and
the world. Heidi and Marc will share preliminary findings, and respond
to comments based on the parallel work that's been done by students. We'll
review the questions which initially motivated student interest in Pluto
and Neptune during the the "Great Planet Debate," and see which have been
answered and which require more analysis or research.
Live uplinks in America will include the Buhl Planetarium at the Carnegie
Science Center in Pittsburgh, Pennsylvania (where students helped make
our original planet selections via interactive technology) and Los Angeles,
California, a school district making a major push to integrate the Internet
into the curriculum. The program will provide considerable "give and take"
between the Planet Advocates and their student "Co-Investigators," as
students witness live the process of testing scientific hypotheses, verifying
results and sharing new findings with peers to substantiate their significance.
Videotaped sequences will document "A Day in the Life...," taking us
behind the scenes as Heidi Hammel works to transform raw planetary data
into new knowledge: Heidi also plans to post a Field Journal of her image
processing successes and (only temporary, we hope!) frustrations on-line.
A second sequence documents the parallel process in one of our participating
schools, where students employ user-friendly and freely accessible graphics
packages to analyze the same data. To help explain the technical steps
in image processing, we see how the stunning images of the Eagle Nebula
(as seen in the co-packaged poster) ends up on the cover of Time for Kids.
Footage from giant storms on Earth, and images from HST and other spacecraft,
allow us to compare and contrast weather on Earth and our neighboring
planets: we come to understand the dynamics underlying the images of (possible!)
bright or dark clouds on Neptune, and seasonal changes (perhaps!) on Pluto.
The concluding tape sequence shows "What's Next?," describing the next
HST Servicing Mission (slated for early 1997), plans for the first-ever
spacecraft mission to study Pluto and Charon closeup, and initial concepts
for a Next Generation Space Telescope, one of whose main functions would
be to search for planets around other stars. Viewers will be reminded
about how to participate on-line, and how to utilize the project on tape
after the live telecast.
Alex Storrs, Planning Scientist, Moving Targets, STScI
It's unfortunate the way a lot of basic science starts in schools these
days with a list of facts to be memorized, and lists of experiments and
discoverersÉthis guy discovered that and that gal discovered this other
thing. This lends a sort of inevitability to the process when it's really
quite haphazard. Its all by guess and by gosh, it's not planned at all.
The chances of finding something new are present in any observation, whether
it's with the Space Telescope, with a ground-based observatory, or made
by somebody from their back yard. People discover comets from their back
yards all the time.
There is a chance, in any observation made by any person, that you'll
find something new, and all you have to do is have an inquiring mind,
and be open, and be alert, and be aware and don't accept as a given everything
that you've been told. Don't accept that the universe is understood, but
rather that the universe is a big, beautiful mystery that we are all trying
You and your Team of Data Analysts are going to take the place of NASA computers
and decipher an image beamed down from space. (This is an actual image,
created in 1979 even though it's been simplified for this activity.) Your
team will be responsible for putting together part of the overall picture.
Your teacher will pass out a special grid and a stream of numbers sent down
by the spacecraft. Encode the grids with the numbers as instructed by the
teacher. As you begin, notice what time it is and write the time here. You'll
receive several sheets of paper, 4 colors ranging from pure white to pure
black. Carefully cut them into squares the size of the grid boxes and attach
the correct squares to the grid as explained by your teacher. When you are
done, your team will have completed one portion of the image. Again, note
the time here.Now, answer the next five questions and when you're finished
tell your teacher that your grid is complete.
What was the total amount of time it took your team to complete its assignment__________?
How many pixels were there in your team's grid__________?
How many teams are there in your class________?
How many total pixels are there in the overall image put together by the
Now your teacher will collect all the completed portions of the image and
put them together so you can see what the spacecraft was seeing.
Finally, consider the following: The total number of pixels in the image
that your class assembled was 1,120. Each pixel had one of four numbers
assigned to it, designating one of four shades of gray, white and black.
That means it took 1,120 x 4, or 4,480 pieces of information to make this
picture. That may seem like a lot but an image of Jupiter from the HST's
Wide Field Camera would use about 640,000 pixels, each of which can have
any one of 2,048 different shades of gray. That makes for a much clearer,
smoother picture but it takes much more information to create it. How
many pieces of information would it take to make such an image________?
Based on how long your DAT took to assemble your part of the image, (put
together 4,480 pieces of picture information) calculate how long it would
take your team to assemble one entire HST image of Jupiter. Write your
NASA computers take less than 5 minutes for the same task. Can you see
why NASA likes to use computers?
DATA STREAM for "Pictures from Outer Spacei"
0000 0001 1100 1100 0112 1112 3333
0000 0100 1211 1110 0120 2233 3333
0001 0010 1221 1111 1120 2333 3333
0001 0000 1122 1111 1122 2333 3333
0011 1000 0022 1101 1122 2323 3333
0112 2100 1022 1101 1111 2223 3333
0122 2210 0102 2211 1111 2223 3333
0121 2222 0101 1111 2111 2122 3333
1211 1112 2111 2211 2110 2212 2333
1211 1111 2211 1221 1101 2212 2333
1210 2211 2221 1222 1111 1122 2333
1210 2222 2221 2122 1111 1112 2333
0210 2222 2222 1112 1222 1121 2233
0120 1122 3222 2111 2211 2121 2233
0021 1222 3322 3211 2100 1211 2233
0021 1223 3332 3212 1000 0121 2223
1012 1112 3332 3212 2000 0021 1223
1012 1112 3333 2312 2000 0012 2223
2111 2121 2333 2322 2100 0002 1223
2111 2111 2333 3332 2210 0001 2223
0210 1211 2233 3332 1221 0001 2313
0220 0221 1222 2232 1222 1001 2333
0211 0022 2222 2332 1212 2222 2233
1012 1002 2222 3232 1222 2222 2223
2001 2101 2233 3332 1221 1122 2332
2300 1210 1123 3332 0122 1211 2332
3210 0012 2223 2332 0112 1212 2333
3221 1100 1222 1221 0011 1122 2333
3222 2221 0123 1222 1011 2222 2333
3321 2212 1001 0112 1011 2232 2333
3321 1221 1000 0111 1001 1222 3233
3331 0122 2110 2111 1000 1212 1323
3331 0122 2111 2121 1100 1122 1333
0001 0120 0000 2111 1100 1122 1333
3332 0120 0000 1210 2100 1122 2232
3332 1100 0010 1111 2100 1121 2332
2323 2100 0011 1222 1110 0122 2222
2323 2110 0111 1122 2221 0112 2222
2332 2122 2211 1112 2121 0112 1222
2332 2111 1011 1122 2222 0112 2222
deep, dark hellish space,
Continuing light years of nothingness
No one can discern the oddities of space.
lands of barren matter,
The blazing, flaming colossal sun
Continues to burn,
Perhaps a herd of bizarre creatures,
and maybe nothing at all,
Perhaps another dimension,
and maybe nothing at all,
No one really knows how we got here,
and maybe we're nothing at all.
Stephen Smethers, Summit Middle School.
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