ASTRONOMICAL INSTRUMENTS.pdf

Astronomical Instruments

1. EARLY ASTRONOMICAL
INSTRUMENTS

2. Sundial
•a device that tells thetime of daywhen
there is sunlight by the apparentposition
of the Sunin thesky

3. Sightline
•orvisual axisis a normally unobstructedline of
sightbetween an intended observer (or
spectator) and a subject of interest
•these were located at some sacred prominent
spots, perhaps over the hilltop, through a cleft in
the hills on the far horizon, along a row of
stones, or from an inner sanctuary
•it determines solstices and equinoxes

4. Stonehenge
•used as a celestial calendar, burial place,
sacrificial altar and a defensive building
during the early times

5. Quadrant
•is an instrument that is used
to measure angles up to 90°
•it was originally proposed by
Ptolemy as a better kind of
astrolabe.
•several different variations of
the instrument were later
produced by medieval Muslim
astronomers

6. The planetary simulator of
Eudoxos
•devised by Eudoxos of Knidos
who tried to simulate the irregular
motion of the planets with the
combination of circular
movements which were
considered the only acceptable
orbits for the eternal motion
•it consisted of two concentric
spheres (or rings) and the internal
sphere rested at inclination in the
exterior sphere and bore the
planet on its equator

7. The planetary system of
Ptolemy
•was the geocentric
astronomical model of
Ptolemy which depicted
and forecasted the
orbits of the Sun, Moon
and known planets on
the ecliptic level

8. The astrolabe of Ptolemy
•it was an exceptional astronomical
instrument which depicted the
celestial sphere and was used for
the measurement of geographic
length (longitude) and width
(latitude) of the observed stars
from any part of the Earth but also
reversely as locator of place (GPS)
and also for the measurement of
the Sun –Moon distance

9. Tetrantas of Hipparhos
(Quadrant)
•it was a measuring instrument
which was used (in astronomy
and navigation) for the
calculation of astronomical
sizes and (in topography and
in construction) for the
measurement of terrestrial
distances (e.g. the height of a
building).

10. The four-cubit dioptra of
Archimedes
•it was an early astronomical instrument
suitable for measuring very small angles
•it was used to calculate the visible angle
and the distance of celestial bodies from
the Earth but also the
distance between them

11. THE TELESCOPE

12. Telescope
•optical instrument that
makes distant objects
appear magnified by using
an arrangement of lenses
or curved mirrors and
lenses, or various devices
used to observe distant
objects by their emission,
absorption, or reflection of
electromagnetic radiation

13. Who invented the Telescope?

14. Did you know?
•The 1600s 1608: Hans Lippershey, a
German-Dutch lensmaker once said that
he wanted to make an instrument “for
seeing things far away as they were
nearby.”
•He was the first person to ever think of the
telescope.

15. Did you know?
•1609: On hearing about this new
instrument, Italian physicist Galileo Galilei
builds his own.
•He improved Lippershey’s design and
using his new telescope the following year,
he discovers the four largest moons of
Jupiter, sunspots on the surface of the
Sun, the phases of Venus and physical
features on the Moon.

16. Important Parts and Functions
of a Telescope

17. Types of Telescope

18. Types of Telescope
➢Refracting Telescope–the light is
collected by a lens called the object
glassor objective, which focuses light
down a tube, forming an image magnified
by an eyepiece

19. Types of Telescope
➢Reflecting Telescope–light is collected
and focused by a concave mirror

20. Types of Spectra
➢Continuous Spectrum–dispersed
radiation is distributed uninterruptedly
over a range of wavelengths
➢Line Spectrum–a gaseous element
gives one or more bright discrete lines at
characteristics wavelength
➢Absorption Spectrum–dark lines or
spaces replace the characteristic bright
lines of the absorbing medium

22. Spectral Classification

23. Any Questions???