Filed astronomy a part of surveying-II. Astronomy usefully a new project planning and construction. These topic cover " Filed Astronomy define & common coordinate systems " according by tabular form.

1. DEPARTMENT OF CIVIL
ENGINEERING
FIELD ASTRONOMY
Er. Ramprasad Kumawat
(M.Tech.)

2. Topic:-
 Definition of Astronomy
 The common coordinate systems

3. Astronomy is the study of the sun, moon, stars, planets,
comets, gas, galaxies, gas, dust and other non-Earthly
bodies and phenomena.
NASA defines astronomy as simple "the study of stars,
planets and space."
Astronomy and astrology were historically associated,
but astrology is not a science and is no longer
recognized as having anything to do with astronomy.
Definition of Astronomy:

4.  In astronomy, a celestial coordinate system is
a system for specifying positions of celestial
objects: satellites, planets, stars, galaxies, and
so on. Coordinate systems can specify a
position in 3-dimensional space, or merely the
direction of the object on the celestial sphere.

5. Modern astronomers tend to fall
into two fields
 The theoretical and The observational.
 Theoretical astronomers model and
analyze how systems may have evolved.
 Observational astronomers focus on
direct study of stars, planets, galaxies, and
so forth.

6.  The coordinate systems are implemented in
either spherical coordinates or rectangular coordinates.
Spherical coordinates, projected on the celestial sphere,
are analogous to the geographic coordinate system used
on the surface of Earth.
 These differ in their choice of fundamental plane,
which divides the celestial sphere into two
equal hemispheres along a great circle.
Rectangular coordinates, in appropriate units, are simply
the cartesian equivalent of the spherical coordinates,
with the same fundamental (x, y) plane and primary (x-
axis) direction. Each coordinate system is named after
its choice of fundamental plane.

7. llowing table lists the common coordinate systems
the astronomical community.
nter point
Origin)
Fundamental
plane
(0° latitude)
Poles Coordinates
Latitude Longitu
bserver horizon zenith / nadir altitude (a) or
elevation
azimuth
enter of
h(geocentric)
center of
(heliocentric)
celestial
equator
celestial poles declination (δ) right
ascensio
or hour ang
ecliptic
ecliptic poles ecliptic
latitude(β)
eclipti
longitude
galactic plane galactic poles galactic latitude
(b)
galact
longitud

8. Horizontal coordinate system
 The horizontal, or altitude-azimuth, system
is based on the position of the observer on
Earth, which revolves around its own axis
once per sidereal day (23 hours, 56 minutes
and 4.091 seconds) in relation to the star
background. The positioning of a celestial
object by the horizontal system varies with
time, but is a useful coordinate system for
locating and tracking objects for observers
on Earth. It is based on the position of stars
relative to an observer's ideal horizon.

9. Equatorial coordinate system
 The equatorial coordinate system is centered at Earth's
center, but fixed relative to the celestial poles and
the vernal equinox. The coordinates are based on the
location of stars relative to Earth's equator if it were
projected out to an infinite distance. The equatorial
describes the sky as seen from the solar system, and
modern star maps almost exclusively use equatorial
coordinates.
 The equatorial system is the normal coordinate system
for most professional and many amateur astronomers
having an equatorial mount that follows the movement
of the sky during the night. Celestial objects are found
by adjusting the telescope's or other instrument's scales
so that they match the equatorial coordinates of the
selected object to observe.

10. Ecliptic coordinate system
 The fundamental plane is the plane of the
Earth's orbit, called the ecliptic plane. There
are two principal variants of the ecliptic
coordinate system: geocentric ecliptic
coordinates centered on the Earth and
heliocentric ecliptic coordinates centered on
the center of mass of the solar system.
 The geocentric ecliptic system was the
principal coordinate system for ancient
astronomy and is still useful for computing
the apparent motions of the Sun, Moon, and
planets.

11. Galactic coordinate system
 The galactic coordinate system uses the
approximate plane of our galaxy as its
fundamental plane. The solar system is
still the center of the coordinate system,
and the zero point is defined as the
direction towards the galactic center.
Galactic latitude resembles the elevation
above the galactic plane and galactic
longitude determines direction relative to
the center of the galaxy.

12. Super galactic coordinate system
 The super galactic coordinate system
corresponds to a fundamental plane that
contains a higher than average number of
local galaxies in the sky as seen from
Earth.

13. Thanks for watching.
 Email ID :
ramkumawat001@gmail.com
 Mobile : 09407156723