The document provides information on astrophysics, astronomy, the universe, galaxies, the Sun, and the layers and components of the Sun. It discusses the history of astronomy and how our understanding has developed since the mid-1800s. It also summarizes the history of the Indian Institute of Astrophysics and the 6-inch telescope located there. The 6-inch telescope's components and how it is used to focus images of sunspots are described.
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Astrophysics and the Universe
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3. Astrophysics, the branch of astronomy that seeks to understand
the birth, and states of celestial objects and systems in terms of
the physical laws that govern them.
Astronomy has developed exponentially since the mid- 1800s,
when the universe was fairly small and uncomplicated plays, and
the view of the cosmos was sun- centric.
Planets were little known cousins of Earth. The stars were
thought to be immutable, and galaxies did not exist. This
information is then interpreted with the aid of theoretical
models.
4. The universe is all of space time and everything that exist therein,
including all planets, stars, galaxies, the content of intergalactic space
the smallest subatomic particles, and all matter and energy.
The observable universe is about 46 billion light years in radius.
Scientific observation of the universe has lead to inference of its earlier
stages.
The big bang theory is the prevailing cosmological model and describe
the earlier development of the universe, which is calculated to have
begun 13.798 ± 0.037 billion years ago.
5. A galaxy is a massive, gravitationally bound system consisting of stars,
stellar remnants, and interstellar medium of gas and dust, and dark
matter, an important but poorly understood component.
The word galaxy is derived from the Greek language literally "milky",
a reference to the Milky Way.
The galaxy nearest to earth is Andromeda.
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9. The Sun is the star at the center of the Solar System.
It is a nearly perfect sphere of hot plasma, with internal convective
motion that generates a magnetic field via a dynamo process.
It is by far the most important source of energy for life on Earth.
Its diameter is about 1.39 million kilometers,( i.e. 109 times that of
Earth, and its mass is about 330,000 times that of Earth), accounting for
about 99.86% of the total mass of the Solar System.
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11. Sun and its layers:
The inner layers are The outer layers are
Convective zone
Radiative zone
Core
The photosphere
The chromosphere
The transition region
The corona
12. Photosphere:
The photosphere is the deepest
layer of the Sun that we can observe directly.
It reaches from the surface visible at the
center of the solar disk to about 250 miles
(400 km) above that. The temperature in the
photosphere varies between about 6500 K at
the bottom and 4000 K at the top (11,000 and
6700 degrees F, 6200 and 3700 degrees C).
Most of the photosphere is covered by
granulation
13. The chromosphere is a layer in the Sun
between about 250 miles (400 km) and 1300
miles (2100 km) above the solar surface (the
photosphere). The temperature in the
chromosphere varies between about 4000 K
at the bottom (the so-called temperature
minimum) and8000 K at the top (6700 and
14,000 degrees F, 3700 and 7700 degrees C),
so in this layer (and higher layers) it actually
gets hotter if you go further away from the
Sun, unlike in the lower layers.
Where it gets hotter if you go closer to the
center of the Sun.
Chromosphere -
14. Transition Region - The
transition region is a very narrow
(60 miles / 100 km) layer
between the chromosphere and
the corona where the temperature
rises abruptly from about 8000 to
about 500,000 K (14,000 to
900,000 degrees F, 7700 to
500,000 degrees C).
15. Corona - The corona is the outermost
layer of the Sun, starting at about 1300
miles (2100 km) above the solar
surface (the photosphere). The
temperature in the corona is 500,000 K
(900,000 degrees F, 500,000 degrees
C) or more, up to a few million K. The
corona cannot be seen with the naked
eye except during a total solar eclipse,
or with the use of a coronagraph. The
corona does not have an upper limit.
Credit: National Solar Observatory
16. telescope
A telescope is an optical
instrument that aids in
the observation of remote objects by
collecting electromagnetic
radiation (such as visible light). The
first known practical telescopes were
invented in the Netherlands at the
beginning of the 17th century, by
using glass lenses. They found use in
both terrestrial applications
and astronomy.
17. History of telescope
The earliest known telescope appeared in 1608 in
the Netherlands when an eyeglass maker named Hans Lippershey tried
to obtain a patent on one.
Galileo improved on this design the following year
and applied it to astronomy.
In 1611, Johannes Kepler described how a far more
useful telescope could be made with a convex objective lens and a
convex eyepiece lens and by 1655 astronomers such as Christiaan
Huygens were building powerful but unwieldy Keplerian telescopes
with compound eyepieces.
18. Types of telescope
There are two basic types of telescopes,
refractors
reflectors
The part of the telescope that gathers the light, called the objective,
determines the type of telescope.
A refractor telescope uses a glass lens as its objective. The glass lens is
at the front of the telescope and light is bent (refracted) as it passes
through the lens.
A reflector telescope uses a mirror as its objective. The mirror is close to
the rear of the telescope and light is bounced off (reflected) as it strikes
the mirror.
19. The history of Indian institute of astrophysics (IIA) stars with creation of
observatory by east India company in madras in 1786 which was later shifted to
Kodaikanal in 1887 and today known as Kodaikanal solar observatory of IIA .
The observatory houses over 100 years of data of the sun.
Then a stellar observatory was started in Kavalur for stellar observation which
is known as Vainu Bhabu observatory both are autonomous institute managed
by government of India.
Its head quarters is in Bangaluru. John Evershed was the first person to contribute
research in this observatory.
historyof Indianinstituteof astrophysics:
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25. History of 6 inch telescope:
Six inch refracting telescope was remodeled by sir Howard Grubb.
This equatorially mounted telescope arrived to madras in 1850 to march
and was erected on the roof of the Astronomers residence it was ready for
use from 1850 April. It was purchased by astronomer caption W.S. Jacob
(born 1813 death 1862) for 500 pounds for his personal use. It was later
purchased by the government.
The original object glass was defective and was replaced by makers in
1852 July.
26. In 1898 the telescope was remodeled by Grubb it was provided with
an electrical drive, and a Grubb portrait lens (Astrographic camera) of
5inches aperture and 36 inches focus was attached to it.
In 1900 the telescope was installed, in the north dome, by the director
C. Michie smith (born 1854 death 1922).
In 1912 the object glass was replaced by a photo visual COOKE
LENS of the same aperture (6 inches). This in turn was replaced by a
visual chromatic lens of the same aperture and focal length in 1918.
Since 1912 the telescope has been weather permitting- for daily direct
heliography of the sun.
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28. INSTRUMENTATION OF SIX INCH TELESCOPE:
3.GUIDE LENSE
1. BARLOW LENS
4.CONCAVE LENS
2.CLOCK ROTATION
29. Guide lens is situated beside the concave
lens, it is used to focus the sunlight at correct tilt
angle.
An instrument can possess the finest
objective lens or mirror.
In our 6 inch telescope using only by lens.
A prime lens is an optic that only offers one focal
length, such as 35mm or 50mm, as opposed to a
zoom lens that can offer a range of focal lengths.
GUIDE LENSE:
30. The Barlow lens, named after Peter Barlow, is a diverging lens which, used
in series with other optics in an optical system, increases the effective focal length of
an optical system as perceived by all components that are after it in the system.
The practical result is that inserting a Barlow lens magnifies the image.
Astronomical Barlow lenses are rated for the amount of magnification they induce.
Most commonly, Barlow lenses are 2x or 3x, but adjustable Barlow’s are
also available. The power of an adjustable Barlow lens is changed by adding an
extensive tube between the Barlow and the guide lens to increase the magnification.
BARLOW LENS:
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32. A concave lens is a lens that possesses at least one surface that curves
inwards. It is a diverging lens, means that it spreads out light rays that have been
refracted through it.
A concave lens is thinner at its Centre than at its edges, and is used to correct
short-sightedness.
It is a diverging lens, meaning that it spreads out light rays that have been
refracted through it.
After light rays have passed through the lens, they appear to come from a
point called the principal focus.
This is the point onto which the collimated light that moves parallel to the
axis of the lens is focused.
CONCAVE LENS:
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34. CLOCK ROTATION:
Focus fast, reliable and
accurate your telescope using
a clock rotation and it control by
mechanical gravitational weight.
White lights are used to focus by
clock rotation.
It has been developed to
meet photosphere layer. Designed
by British people completely
works by mechanical strength.
38. PHOTOGRAPHIC PLATE
Photographic plates preceded photographic film as a capture medium in
photography. The light-sensitive emulsion of silver salts was coated on a glass plate,
typically thinner than common window glass, instead of a clear plastic film.
The emulsion will gradually darken if left exposed to light, but the process is too
slow and incomplete to be of any practical use. Instead, a very short exposure to the
image formed by a camera lens is used to produce only a very slight chemical
change, proportional to the amount of light absorbed by each crystal.
This creates an invisible latent image in the emulsion, which can be
chemically developed into a visible photograph. In addition to visible light, all films
are sensitive to ultraviolet, X-rays and high-energy particle.
40. PHOTOGRAPHIC FLIM:
Photographic film is a strip or sheet of transparent plastic film base coated on one side with
a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The
sizes and other characteristics of the crystals determine the sensitivity, contrast
and resolution of the film.
The emulsion will gradually darken if left exposed to light, but the process is too slow and
incomplete to be of any practical use. Instead, a very short exposure to the image formed by
a camera lens is used to produce only a very slight chemical change, proportional to the
amount of light absorbed by each crystal.
This creates an invisible latent image in the emulsion, which can be chemically developed into
a visible photograph. In addition to visible light, all films are sensitive to ultraviolet, X-
rays and high-energy particles.
41. Telescope mounting:
A telescope mount is a mechanical structure which supports a telescope. Telescope
mounts are designed to support the mass of the telescope and allow for accurate pointing of the
instrument. Many sorts of mounts have been developed over the years, with the majority of effort
being put into systems that can track the motion of the fixed stars as the Earth rotates.
Their types:
Equatorial mount:
:
Transit mount:
Altitude-Altitude mount:Altazimuth mount:
42. The equatorial mount has north-south "polar axis" tilted to be parallel to Earth's polar
axis that allows the telescope to swing in an east-west arc, with a second axis
perpendicular to that to allow the telescope to swing in a north-south arc.
Slewing or mechanically driving the mount's polar axis in a counter direction to the
Earth's rotation allows the telescope to accurately follow the motion of the night sky.
Equatorial mounts come in different shapes, include German equatorial mounts(GEM in
short), equatorial fork mounts, mixed variations on yoke or cross-axis mounts,
and equatorial platforms such as the Poncet Platform.
Equatorial mount:
43.
44. Differential rotation is seen when different parts of a rotating object move with
different angular velocities (rates of rotation) at different latitudes and/or depths
of the body and/or in time.
This indicates that the object is not solid. In fluid objects, such as accretion disks,
this leads to shearing. Galaxies and protostars usually show differential rotation;
examples in the Solar System include the Sun, Jupiter and Saturn.
In a rotating solid body, regions that are adjacent at one point in time will remain
adjacent as the body rotates. This means that points further from the rotation
centre will travel at greater speeds than those closer in.
If the rotating body is not solid, however, regions that are adjacent at one point in
time do not necessarily maintain that configuration. This is known as ‘differential
Differential rotation:
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49. COMMUNICATIONS ANTENNAS
On-board the Hubble telescope are two identical
S-Band transmitters. In 1998 one of the transmitters
failed, however the secondary transmitter has kept
up with the extra load by rotating the telescope to
maintain communication. The radio waves
converted from the solid-state recording system are
sent to a NASA communication satellite, which in-
turn relays the information to Earth.
50. The adaptive optics on the Hubble telescope
allow it to conduct high-resolution optical
visualization over a wide field of view. The
aperture door itself can be closed if needed,
to prevent light from external sources from
entering the telescope.
APERTURE DOOR