Download Comparison of Solar Energy Output Variations Over Three Days in

Radio Astronomy
Prepared by Marcia Barton
and Karen Gram
July 28, 2006
Overview
•
•
•
•
•
•
Optical Astronomy
The Electromagnetic Spectrum
Radio Astronomy
Project Objective
Data from Project
Conclusions
Optical Astronomy
• This optical wavelength
picture shows the large
spiral galaxy M31 (also
known as the Andromeda
Galaxy) and its small
companions M32, lower
center, and M110, to the
upper right. Andromeda
is the Milky Way’s closest
large neighbor at a
distance of about 2.2
million light-years, and it
is very similar in
appearance to, and
slightly larger than, the
Milky Way.
B. Schoening (National Optical Astronomy Observatories) and V. Harvey
(University of Nevada, Las Vegas)
Pinwheel Galaxy
(M33, NGC 598)
M33 in the constellation Triangulum is a prominent
nearby spiral galaxy about 3 million light-years away.
Whirlpool Galaxy
(M51, NGC 5194/5)
• This showpiece in Ursa Major is likely one of the finest and
most photographed objects in the night sky.
Hydra Cluster of Galaxies
(Abell 1060)
• Two nearby
stars frame
this cluster of
galaxies in
the constellation Hydra.
Mars
Saturn
REU program, N.A.Sharp/NOAO/AURA/NSF
Voyager 2 Nasa photo
Image courtesy of Nasa
Moon
Solar System
What is an Electromagnetic Wave?
• Radio waves, television
waves, and microwaves
are all types of
electromagnetic waves.
They only differ from
each other in wavelength.
Wavelength is the
distance between one
wave crest to the next.
• Waves in the electromagnetic spectrum vary in
size from very short gamma-rays smaller than
the size of the nucleus of an atom to very long
radio waves the size of buildings.
Move about Wavelengths…
• One way we measure the energy of an electromagnetic
wave is by measuring its frequency.
• Frequency refers to the number of waves a vibration
creates during a period of time—like counting how
frequently cars pass through an intersection.
Let’s do an activity to show how
wavelength and frequency are
related!
Wavelength and Frequency
• In general, the higher
the frequency, or
number of waves, the
greater the energy of
the radiation.
• In other words, the
shorter the wave, the
higher the energy.
Electromagnetic Waves
• The satellite dish connected
to the television receives the
signal, in the form of
electromagnetic waves, that
is broadcasted from the
satellites orbiting the Earth.
The image is displayed on
your television screen.
Radio Telescopes
Very Large Array (VLA) Radio Telescope in New
Mexico seen from the air
Because the wavelengths of radio light are so large, a radio telescope
must be physically larger than an optical telescope to be able to
make images of comparable clarity.
Can you find your teacher inside
the VLA Radio Telescope?
Image courtesy of Robyn Harrison
Image courtesy of NRAO/AUI
Radio Astronomy
NGC 326 – Data from the Very Large
Array Radio Telescope in New Mexico is
the first direct evidence that black holes
actually do coalesce
• Radio waves have the
longest wavelengths in the
electromagnetic spectrum.
These waves can be longer
than a football field or as
short as a football.
Image courtesy of NRAO/AUI and Inset: STScI
What is Radio Astronomy?
Many astronomical
objects emit radio
waves, but that fact
wasn't discovered
until 1932. Since
then, astronomers
have developed
sophisticated
systems that allow
them to make
pictures from the
radio waves emitted
by astronomical
objects.
Image courtesy of NRAO/AUI and A. C. Boley and L. van Zee, Indiana
University; D. Schade and S. Côté, Herzberg Institute for Astrop.
How can radio waves “see”?
• Objects in space, such as
planets and comets, giant
clouds of gas and dust, and
stars and galaxies, emit light at
many different wavelengths.
Some of the light they emit has
very large wavelengths sometimes as long as a mile!
These long waves are in the
radio region of the
electromagnetic spectrum.
• An optical telescope could not
see this object in space
because it would be blocked
by the giant dust and gas
clouds. Radio ways can pass
right through the dust and gas,
so that an image can be
formed.
Image courtesy of NRAO/AUI and David Thilker (JHU),
Robert Braun (ASTRON), WSRT
Why Use Radio Telescopes?
• Radio astronomy can be done
during the day as well as the
night.
• Radio astronomy has the
advantage that sunlight,
clouds, and rain do not affect
observations.
• Some celestial objects can not
be seen in the visible part of
the spectrum but do emit radio
waves, so they can be imaged.
• “Radio telescopes are used to
measure broad-bandwidth
continuum radiation as well as
spectroscopic features due to
atomic and molecular lines
found in the radio spectrum of
astronomical objects.”
• Radio telescopes can detect
atoms and molecules that can
not be seen with an optical
telescope. These atoms and
molecules tell scientists
important information about
how stars and galaxies form.
The Milky Way
Image courtesy of NRAO/AUI
• This composite picture shows the distribution of atomic
hydrogen in our galaxy.
The Milky Way in Different
Wavelengths
Jodrell Bank Mark I and Mark IA, Bonn
100-meter, and Parkes 64-meter
Seen with radio
waves in the
408 Mhz frequency
NASA/CXC/M.Weiss
Seen with the Chandra
X-Ray telescope
Seen in the infrared
wavelength
Diffuse Infrared Background Experiment (DIRBE)
Radio Astronomers Have
Discovered a Lot About the Milky
Way!
With radio telescopes,
astronomers have
discovered
• The shape and size of
our galaxy!
• The black hole in the
center of our galaxy!
• Stars forming and
dying!
Image courtesy of NRAO/AUI and N.E. Kassim, Naval
Research Laboratory
Let’s take a closer look at some
astronomical objects in optical,
radio and other wavelengths!
Comparison of Solar Energy
Output Variations Over Three
Days in Different Frequencies
Prepared by Marcia Barton
and Karen Gram
July 28, 2006
Project Overview
• We used the small radio
telescope to measure the
energy output of the sun on
three separate days at
approximately the same time
each day, then compare the
radio images with optical
images of the sun at as near
the same time as we could
obtain.
• We also look at the raw data
we obtained from the small
radio telescope to see if that
data would give us more
detailed information than the
raster map.
Screen shot of the small radio telescope operating software.
Project Overview
• Using the small radio
telescope, continuum
measurements were
taken in the default
frequency of 1420
MHz. A 25-point grid
scan was used to
obtain the raster map.
Images of the Sun On July 24, 2006
Raster map imaged by the small radio telescope
SOHO Magnetogram image taken July 24, 2006
Images of the Sun On July 24, 2006
Raster map imaged by the small radio telescope
SOHO Extreme Ultraviolet image taken
July 24, 2006
Optical wavelength of sun taken July 24, 2006
Images of the Sun On July 25, 2006
Images of the Sun On July 25, 2006
Srt raster map 7.25.06
SOHO Extreme Ultraviolet images 7.25.06
Images of the Sun On July 26, 2006
Optical sun taken by the National Solar
Observatory on July 26, 2006
SOHO IMAGES
Srt raster map
Solar and Heliospheric
Observatory (SOHO) has an Extreme
ultraviolet Imaging Telescope (EIT)
that images the solar atmosphere at
several wavelengths, and therefore,
shows solar material at different
temperatures. In the images taken
at 304 Angstroms the bright material
is at 60,000 to 80,000 degrees
Kelvin. In those taken at 171, at 1
million degrees. 195 Angstrom
images correspond to about 1.5
million Kelvin. 284 Angstrom, to 2
million degrees. The hotter the
temperature, the higher you look in
the solar atmosphere.
SOHO EIT 284 image taken July 26, 2006
Image of the Sun On July 28, 2006
SOHO EIT 284 image 7.28.06
Data From the Small Radio
Telescope
Comparison over 3 days
60000
50000
power
40000
30000
20000
10000
0
0
5
10
15
time
20
25
30
Data From the Small Radio
Telescope
Rescaled Comparison Data
20000
18000
16000
14000
Power
12000
10000
8000
6000
4000
2000
0
0
5
10
15
time
20
25
30
Information from SOHO
• Over the past few weeks (date July 21, 2006) this extreme
ultraviolet observing instrument on SOHO has witnessed at
least four events where pieces of the Sun have blasted off
into space. In most instances these are evidence of coronal
mass ejections, solar eruptions that occur fairly frequently.
Magnetic tensions above active regions strain and break
apart, propelling solar particles into space at millions of miles
per hour.
• The first event on June 26th appears to have been triggered
by the collapse of a solar prominence suspended by magnetic
forces above the Sun. While these clouds of particles are
large, they hardly diminish the bulk of the Sun at all. Don't
worry: there's plenty left for billions of years to come.
Conclusions
• The raster map is a contour map of the energy
output of the sun. Although the raster images
were similar on different days, closer
examination of the raw data showed a difference
of two to three times the magnitude of the
energy measured.
• This could be a calibration error of the small
radio telescope. The data was rescaled to
account for the possible calibration error. When
the data was rescaled, there was not much
difference in the radio telescope measurements
over the three days.
Conclusions
• When comparing the radio telescope image to
images made in different wavelengths, UV and
optical, it is possible that the solar sunspot and
flares shown on the UV correspond to the
irregular shape of the raster map.
• However, more extensive data collection would
be needed to obtain baseline data for the sun
and insure accurate calibration of the small radio
telescope.
References
National Radio Astronomy Observatory. August 6, 2004.
http://www.nrao.edu/whatisra/FAQ.shtml. July 26, 2006
Sky and Telescope. www.skyandtelescope.com. July 24, 2006.
Hubble. http://hubblesite.org/ July 27, 2006.
Nasa Astronomical Data Center. http://adc.gsfc.nasa.gov/ July 25, 2006
National Optical Astronomy Observatories.
National Solar Observatory. http://www.nso.edu/ July 27, 2006.
SOHO. Solar and Heliospheric Observatory. July 28, 2006.
http://sohowww.nascom.nasa.gov/ downloaded July 24-27, 2006.
References
And of course…..
Thank you Lisa Young and
Robyn Harrison for all your
kind and informative help!