Download Volume 1 (Issue 7), July 2012

SUPARCO - ASTRONOMY & ASTROPHYSICS
BULLETIN
Volume I, Issue 7
July, 2012
Sky watching: Naked Eye Phenomenon
Pakistan Space Vision-2040, was
approved by the Prime Minister of
Pakistan which inter-alia included
augmentation / strengthening of
the Astronomy and Astrophysics
programmes of SUPARCO.
SUPARCO`s
astronomy
and
astrophysics program is mainly
focused on theoretical and
observational research. For this
an astronomical observatory is
planned to be established.
Research studies pertaining to
deep space objects including
galaxies, nebulae and variable
stars are also being initiated.
Search for earth like planets is a
hot
topic
in
astrophysics
nowadays. It is planned to conduct
research studies in this field also.
Inside this Issue:
Sky watching: Naked eye
Phenomenon
Looking at the sky for observation of heavenly bodies is usually termed as sky
watching. Each object in the sky has its own exquisite loveliness. Besides the
stars, there are planets, the moon, shooting stars and comets to observe. If no
special events are there, people can even observe certain naked eye sky
phenomena. These phenomena require no instrumental aid and any one can
observe these phenomena.
Some of them occur in the earth’s atmosphere in daytime and some in the
nighttime. These include rainbows, auroras and meteors for example, occurring
just few miles above the earth surface.
Atmospheric effects on sunlight
Sunlight reaches earth after travelling 93 million miles The passage of sunlight
through the atmosphere, changes it’s properties and sometimes causes various
atmospheric phenomena to occur.
Halos: One of these is the “Halo” around the sun and the moon. High in the
atmosphere, the six-sided ice crystals in cirrus clouds refract (or bend) light in
the same way a prism does. This creates a halo around the Sun with a radius of
22°. Halo around the sun are sometimes not noticeable because of its glare but
people can perceive when the sun is obscure by objects or buildings.
White Dwarf Stars
Book Review
Ecliptic
Sky this Month
Web Review
Software Review
Understanding the space weather
Distrubed geomagnetic conditions
monitored by SUPARCO
9
10
Transit of Venus
Events of the Month
Date
Time
Event\Direction
03 Jul
After
Sunset
Full Moon\ East
15 Jul
Before
Sunrise
After
Sunset
Pleisdes,Moon, Jupiter,
Venus\ East
New Moon\ West
24 Jul
After
Sunset
Moon, Mars,
Saturn and Spica\ West
28 Jul
After
Sunset
Delta Aquarids
Meteor Shower\ East
20 Jul
Halo and Sun dog
Sun dogs: Another atmospheric phenomenon that is related to haloes is called
sun dogs. Sun dogs or parhelia are atmospheric phenomena that create bright
spots of light in the sky, often on a luminous ring or halo on either side of the sun.
When light refracts through flat horizontal ice crystals, you might see bright
spots of light along the right and left sides of a halo. Sundogs may also appear
as a colored patch of light to the left or right of the sun. They can be seen
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page II
anywhere in the world during any season, but they
are not always obvious or bright. Sundogs are best
seen and are most conspicuous when the sun is low.
Light Pillars: Sun Pillars appear most often at
sunrise and sunset as a vertical shaft of light
extending upward or downward from the sun. They
are formed by reflection of sunlight through ice
crystals. Pillars also form when hexagonal plate like
ice crystals fall with their flat bases oriented
horizontally. As they fall, they tilt from side to side
and reflect the light off the tipped surfaces of the
crystals. A bright area is then produced above or
below the sun.
Mirage
Crepuscular Rays: Crepuscular rays are rays of
sunlight that appear to radiate from a single point in
the sky. These rays, which stream through gaps in
clouds or between other objects, are columns of sunlit
air separated by darker cloud shadowed regions. The
name comes from their frequent occurrences during
crepuscular hours (those around dawn and dusk),
when the contrasts between light and dark are the
most obvious.
Carpesculated Rays
Light Pillar
Mirage: Mirage are formed when light is bent as it
passes through the atmosphere having varying
densities. When the sun heats the earth’s surface,
the air closer to the ground is warmer and less dense
than layers of air higher in the atmosphere. As light
travels from a less dense medium to a denser
medium at an angle, the light is bent toward the
normal. As light travels from a dense medium to a
less dense medium at an angle, the light is bent
away from the normal. We see mirages as
shimmering or watery spots on hot surfaces,
inverted reflections of distant objects, and other
objects appear taller than they really are.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Glory: A common optical phenomenon involving
water droplets is the glory. A glory is an optical
phenomenon, appearing much like an iconic Saint's
halo about the head of the observer, produced by light
backscattered (a combination of diffraction, reflection
and refraction) towards its source by a cloud of
uniformly-sized water droplets. A glory has multiple
colored rings, with red color on the outermost ring and
blue/violet colors on the innermost ring.
The angular distance is much smaller than a rainbow,
ranging between 5° and 20°, depending on the size of
the droplets. The glory can only be seen when the
observer is directly between the sun and cloud of
refracting water droplets. Hence, it is commonly
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observed while airborne. Glory can also be seen from
mountains and tall buildings, when there are clouds
or fog below the level of the observer, or on days with
ground fog.
Because rainbows are light and because light rays
strike everyone's eyes a little differently, the rainbow
one see will be a little different from the one someone
else sees.
Auroras: An aurora is a natural light display in the sky,
particularly in the Polar Regions, caused by the
collision of charged particles directed by the Earth's
magnetic field. An aurora is usually observed at night
and typically occurs in the ionosphere.
Glory
Rainbows: A rainbow is visible light broken into it’s
components what we see as seven colors: red,
orange, yellow, green, blue, indigo and violet. They
always appear in the same order, with red on top and
violet on the bottom, in a main rainbow. In a secondary
rainbow, they appear in the opposite order.
Rainbows are light refraction phenomenon. One can't
touch them. One can't reach around behind them.
They exist only in the eyes and sometimes the
photographs of the people who see them. Three
things must happen for one to see a rainbow's colors.
First, the sun must be shining. Second, the sun must
be behind one, and third, there must be water drops in
the air in front of one. Sunlight shines into the water
drops, which act as tiny prisms that bend or "refract"
the light and separate it into colors. Each drop reflects
only one color of light, so there must be many water
drops to make a full rainbow. One will see the brightest
rainbows when the water drops are large, usually right
after a rain shower.
Auroras
Meteors Showers: Meteor showers are one of the
major night sky phenomena, occurring in different time
of months throughout the year. Following table
illustrates the occurrence and the source of
generation of meteor showers,
The name of each meteor shower is taken from its
appearance in the respective constellation in the
sky. For example Orionids has its radiant point (from
where the meteors appear to come) lies in Orion
constellation.
Rainbow
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page IV
White Dwarf Stars
The degenerated core of a dead star is called white
dwarf. It is very dense and possesses mass
comparable to that of the Sun and volume to that of
the Earth. One tea spoon of the white dwarf
material weighs about 6500kg or over 7 metric tons.
It emits faint white light due to stored thermal
energy.
Formation of White dwarf: White dwarfs are very
faint small in size and hard to detect. Only a few
ones are known. We find most of them as
members of binary systems. Even the brightest
star, Sirius, has a white dwarf companion, named
as Sirius B(shown in figure below). In January
2009, the project of “Research Consortium on
Nearby Stars” discovered eight white dwarfs
among the hundreds star systems nearest the
Sirius B
Stars in their red giant phase start to burn helium
by triple alpha nuclear process and convert helium
into carbon and oxygen. The core of star shrinks
further due to gravitational force when helium fuel
is exhausted. Those stars which do not have
enough mass to fuse carbon and oxygen end their
lives in the form of a beautiful planetary nebula with
central degenerated core (white dwarf). White
dwarf is unable to create internal pressure (e.g.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
release of energy from fusion, as it has ceased),
gravity compacts the matter inward until the electrons
that compose a white dwarf's atoms, is smashed
together. In normal circumstances, identical electrons
(those with the same "spin") are not allowed to occupy
the same energy level. Since there are only two ways
an electron can spin, only two electrons can occupy a
single energy level. This is what's known in physics as
the Pauli’s Exclusion Principle. In a normal gas, this
isn't a problem because there aren't enough electrons
floating around to fill up all the energy levels
completely. But in a white dwarf, the density is much
higher, and all of the electrons are much closer
together. This is referred to as a "degenerate" gas,
meaning that all the energy levels in its atoms are filled
up with electrons. For gravity to compress the white
dwarf further, it must force electrons where they
cannot go. Once a star is degenerate, gravity cannot
compress it anymore, because quantum mechanics
dictates that there is no more available space to be
taken up. So our white dwarf survives, not by internal
fusion, but by quantum mechanical principles that
prevent its complete collapse.
Degenerate matter has other unusual property. For
example, the more massive a white dwarf is, the
smaller it is. This is because the more mass a white
dwarf has, the more its electrons must squeeze
together to maintain enough outward pressure to
support the extra mass. However, there is a limit on
the amount of mass a white dwarf can have.
Subrahmanyan Chandrasekhar discovered this limit to
be 1.4 times the mass of the Sun. This is appropriately
known as the "Chandrasekhar limit." No white dwarf
beyond this limit has yet been observed.
Page V
Software Review
The Fate of white dwarf: White dwarf stars have all
the energy they will ever have. Over billions of years,
they will gradually radiate the energy stored in the
motion of their hot positive ions (carbon and oxygen
nuclei). We can call them “retired stars,” since they
are spending their life savings of stored energy; they
are not undergoing nuclear fusion process as the
normal stars do. White dwarfs eventually become so
cool and dim that they can no longer be seen, at least
not easily and these objects are known as “black
dwarfs” but there is no clear boundary between a
white dwarf and a black dwarf.
White dwarf can accrete mass from companion in
binary system and can cause a catastrophic explosion
of the universe called “Type 1A Supenova”. In other
case merger of two white dwarfs can cause the same
explosion. Type 1a supernovae are used by
astrophysicists as standard candles to measure
relative distances between galaxies.
Cartes du Ciel is a free planetarium program
developed by Patrick Chevalley, the author of “Virtual
Moon Atlas” (reviewed in January 2012 issue). This
software is available for Linux, Mac OS X and
Windows.
This program enables one to draw sky charts, making
use of the data in 16 catalogs of stars and nebulae. In
addition, the position of planets, asteroids and
comets are shown.
The purpose of this program is to prepare different
sky maps for a particular observation. A large number
of parameters help to choose specifically or
automatically which catalogs to use, the color and the
dimension of stars and nebulae, the representation of
planets, the display of labels and coordinate grids,
the superposition of pictures, the condition of visibility
and more. All these features make this celestial atlas
more complete than a conventional planetarium.
Merger of two white dwarfs causing type 1a
supernova
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
The software is comparable to other commercially
planetarium programs (Skymap pro) that range
around 70 dollars whereas Cartes Du Ciel is
absolutely free to download and spaced around 15
MB. There are 15 supported catalogs, including
Tycho and the Guide Star Catalog, though only the
Bright Star Catalog and SKY2000 are included in the
base distribution. This is a reasonable approach
since some catalogs are huge, and it does keep the
distribution size down to around 15MB. But even with
the two small catalogs, you can view 300,000 stars
down to magnitude 9.
Page VI
Sky this Month
July 1, 2012 – Aldebran, Jupiter, Venus and
Pleiades
Before the dawn timings of July 1, the two brightest
planets, Venus and Jupiter, will be in company with
a red giant star, Aldebran, and an open cluster of
nearly 200 stars, Pleiades. This can be viewed in
Eastward direction early in the morning.
to the clear sky. Clouds and haze may cause
problems in viewing the new moon.
Position of the moon at the time of sunset in Karachi
July 24, 2012 – Moon, Mars, Saturn and Spica
The Last quarter moon will be showing a tetrahedral
along with Mars, Saturn and a fairly bright bluish
white star of constellation Virgin , Spaica in the sky.
The view would be visible in the Westward direction
July 15, 2012 –Pleiades, Moon, Jupiter, Venus
and Aldebran
The situation will be observed 2 week later changes
as on July 15 the waning moon will now have its
proximity with Jupiter which has attained some
altitude during this period. Venus and Aldebran
would also be lying fairly above the horizon after
two weeks. Same timings and direction would be
implied as of July 1.
July, 28, 29, 2012- Meteor Shower
The South Delta Aquarids can produce about 20
meteors per hour. Radiant point for these meteors is
in the constellation Aquarius.
July 20, 2012 - New Moon
Chance of new moon visibility in the sky would be
favorable although the visibility would be subjected
to the clear sky. Clouds
and
Position of the
moonhaze
at the timemay
of sunsetcause
in Peshawar
problems in viewing the new moon.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page VII
Web Review
Book Review
Supported by NASA, The NSSDC Photo Gallery is
intended to fulfill two different purposes. The first of
these is to provide access to some of the more
popular NASA images available to the public. NSSDC
fills hundreds of requests per year for thousands of
photographs, but many of the same images are
requested time and again. Many of these are
provided in the Photo Gallery.
Astronomy For Dummies tells what you need to know
to make sense of the world above us. Written by one
The second purpose of the Photo Gallery is to of the most well-known astronomers in the world, this
provide examples of images produced from CD-ROM fun, fact-filled, and accessible guide fills you in on the
data. The images presented in the Photo Gallery basic principles of astronomy and tells you how to:
have a number of different sources, primarily NASA
missions, however. They are generally organized by •Identify planets and stars
object and/or phenomenon on separate pages. The •Explore our solar system, the Milky Way, and
source of the images as well as the processing beyond
involved in producing the image have been included •Understand the Big Bang, quasars, antimatter, black
wherever possible. Photo captions for some images holes, and more
are also available.
•Join the Search for Extraterrestrial Intelligence
The photo gallery list images by the following topics,
Planetary
Astronomical Objects
Others; including Sun and Space crafts
And indexes which includes Hubble space telescope,
Galileo and Voyager.
The images are shown on the pages as reduced
versions ("thumbnails") of the full images. Most of the
full images are in JPEG format. Because of the large
number of thumbnails on some pages, you may wish
to turn off automatic loading of images if you are
accessing these pages via a slower dial-up
connection. To retrieve the full images (for on-line
viewing and/or to save them), select the reduced
version.
A limited number of the images in the Photo Gallery
are also available on the FTP site in TIFF format in a
high-resolution form. Links appear when this option is
also available.
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
(SETI)
•Get the most out of planetarium visits
•Make more sense out of space missions
From asteroids to black holes, quasars to white
dwarfs, Astronomy For Dummies takes you on a
grand tour of the universe. Featuring star maps,
charts, gorgeous full-color photographs, and
easy-to-follow explanations it gives you a leg up on
the basic science of the universe. Topics covered
include:
•Observing the night sky, with and without optics
•Selecting binoculars and telescopes and positioning
yourself for the best view
•Meteors, comets, and man-made moons
•Touring our solar system and becoming familiar with
the planets, asteroids, and near earth objects
•Our Sun, stars, galaxies, black holes and quasars
•SETI and planets revolving around other suns
•Dark matter and antimatter
•The Big Bang and the evolutions of the universe
Page VIII
Understanding Space Weather
The objective of this article is to develop an understanding of space weather for readers with less or no
scientific knowledge. The difference between tropospheric and space weather has been addressed in the
article. References have been given at the end for further reading.
Weather: All of us are familiar with the term 'weather' which presents the state of atmosphere at a particular
location on Earth at a given time. The weather we come across daily gives the condition of troposphere
(which is the lowest region of the atmosphere of Earth having an average height of 18 km). Any phenomenon
taking place in this region of the Earth's atmosphere alters the weather.
At the time of writing these lines the weather of
Karachi
from
a
weather
website
http://www.wunderground.com/ was observed as
shown in the Figure 1. It is clear from the figure that
weather of Karachi on the given day is partly cloudy
with a temperature of 34 C and a wind speed of
30km/hr. The figure informs about the sunrise/set
times and phase of moon also. Additionally, a 5 day
forecast has been presented mentioning the
temperature and condition of the weather at
Karachi.
A person seeking information about the weather
can easily understand the atmospheric conditions
by looking at one such forecast as presented.
Weather of Karachi on 24-May-2012 at 1230PST
Space Weather: On the other hand, Space Weather is a concept which describes the changes in the Sun
and their impacts on the environment of Earth. The term space weather was apparently coined in 1972 by
a memo of US Air Force, whereas the common use of the term started in 1990s.
Definitions: There are various ways of defining the space weather, some of the definitions from different
sources have been mentioned below.
"The time varying conditions in the near-Earth space environment that may affect space-borne or
ground-based technological systems and may endanger human health or life are referred to as space
weather." (Singh, 2010)
This definition talks about the effects of space weather on the Earth environment and technology.
"Space weather is a consequence of the behaviour of the Sun, the nature of Earth's magnetic field and
atmosphere and our location in the solar system." (Goodman, 2004)
It is clear from the definition above that space weather is a result of solar behaviour. Any variation or
disturbance in Sun can alter the space weather which can be experienced in the solar system. Below is a
more comprehensive definition of the term which combines both the above mentioned definitions.
"The term space weather is defined as the conditions on the Sun and in the solar wind, Earth’s
magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of
space-borne and ground-based technological systems and endanger human life or health." (Eastwood,
2008)
References:
Eastwood, J. P. [2008], "The science of space weather", Philosophical Transactions of The Royal Society
A, Vol 366, pp 4489-4500
Goodman, J. M. [2005], "Space Weather & Telecommunications", Springer
Singh, A. K., Siingh, D., Singh, R. P. [2010]. "Space Weather: Physics, Effects and Predictability", Surveys
in Geophysics, Vol 31, pp 581-638
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page IX
Disturbed storm condition monitored by SUPARCO
The space weather monitoring facilities at SUPARCO recorded geomagnetic disturbances during 16-18
June, 2012 caused by 02 Coronal Mass Ejections which erupted on the June 13th and June 14th, 2012. The
CME’s shockwave hit the Earth’s Magnetic Field on the 16th June, 2012 causing strong variation in the
geomagnetic field as shown by the Magnetograms of the Abdus Salam Geomagnetic Observatory and the
Islamabad Geomagnetic Observatory below.
The magnetograms of the Abdus Salam Observatory show disturbed geomagnetic variation during 16-18 July, 2012
The magnetograms of the Islamabad Geomagnetic Observatory show disturbed geomagnetic variation during 16-18
The picture on the right shows the
active region on the Sun which
caused a long duration M-class flares
for two consecutive days in a row
which hurled 02 CMEs one after the
other towards Earth causing the
Geomagnetic Storms recorded in the
Magnetograms above.
Ghulam Murtaza
General Manager
Gulzar-e-Hijri SUPARCO Road
Sector 28, SUPARCO, Karachi, Pakistan
Tel: 021-34690765-74
Fax 021-34690795
Email: [email protected]
Image taken by NASA's Solar Dynamics Observatory (SDO) showing the
active region emitting high energy solar radiation
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
Page X
Transit of Venus June 06, 2012
Transit of Venus 2012 will remain one of the memorable astronomical event ever observed. SUPARCO was
preparing two weeks prior to the event . A setup of a small hut at the rooftop of the building with all necessary
connections was made. The telescope used was an 8 inch SCT with Badeer and H alpha filter for our
observation of the transit. The first two contacts of the transit were not observable as the Sun was below the
horizon in Karachi. It was feared that morning of June 06 could be cloudy and there would be no chances
of observing the event from Karachi.
The sunset timing was 05:42 AM local time but it was very hazy in the morning. The first time when the sun
came into a clearer view was at 07:15 AM. Prime focus method was used for observing the transit. A DSLR
was directly attached with the telescope and the transit was visible in the display monitor of camera so that
multiple visitors could view the event at a time. Around 100 employees of SUPARCO witnessed that
historical event.
Track of Venus on the solar disk during transit June 06, 2012
Contact Information
Links to website:
More Image Video of transit of Venus 2012 can be seen at the official website of SUPARCO by following the
link http://www.suparco.gov.pk/pages/astronomy-bulletin.asp
Rizla Zareen
General Manager
Gulzar-e-Hijri SUPARCO Road
Sector 28, SUPARCO, Karachi, Pakistan
Tel: 021-34690765-74
Fax 021-34690795
Email: [email protected]
SUPARCO - ASTRONOMY & ASTROPHYSICS Bulletin is a monthly publication
This bulliten can be downloaded from the official website of SUPARCO