Astronomy and the invention of Telescope of Galileo. Discovery of the moon of Jupiter

1. Astronomy before the invention of
Telescope
▪ Even before the telescope
was invented, many
astronomical phenomena
were already observed and
recorded.
▪ Pleiades star cluster – The
Pleiades is a star cluster
to the unaided eye. Once
this star cluster appear in
the sky, the Incas mark
this as the start of year,

2. Constellations
Across cultures, ancient civilizations saw different
patterns and shapes in the constellations.
Ancient Egyptians considered the constellations as
representations for their gods such as “Orion” which
represented Osiris, the death, rebirth, afterlife.
Ancient people have also used these to determine
when to plant and harvest crops.
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3. First sight of Venus
This planet is
considered the third
the brightest in the
sky.
In Mayan culture, the
position of Venus was
used as a basis in
deciding whether to
start a battle against
another tribe
A platform of Mayan for observation
of Venus

4. Saving the Appearances
Before Copernicus, the Greek believers of
the geocentric models observed a paradigm
of “ saving the appearances” which meant
that their primary concern was the soundness
of the mathematical model and not its
applicability to reality.

5. Thus, for as long as the theory was backed up
with a good mathematical model regardless of
the absence of physical explanations for the
phenomena, it would still be acceptable.
This was the reason why the Ptolemaic model
of the universe prevailed for a long period of
time even when the heliocentric model started
to gain acceptance in the astronomical
community.

6. The ideas of the Greeks about the universe were
constrained. Another effect of this paradigm was the
dismissal of questions on the irregularities of the
motion of planets (which means that it is possible that
they are not moving in uniform circular motion).
If these questions were discussed and answers were
searched for, Ptolemaic system would definitely
weaken.

7. Who invented the telescope?
▪Hans Lippershey, credited
with invention of the telescope.
▪The first person to apply for a patent for
a telescope was a Dutch eyeglass maker
named Hans Lippershey (or Lipperhey). In
1608, Lippershey tried to lay claim on a
device with three-times magnification.

8. ▪Galileo Galilei did not invent
the telescope but was the
first to use it systematically
to observe celestial objects
and record his discoveries.
His book, Sidereus nuncius
or The Starry Messenger
was first published in 1610
and made him famous.

9. The Universe in the Galileo’s Eyes
Galileo Galilei’s use of telescope for
astronomical purposes caused paradigms
to shift.
His telescope allowed him to discover
many significant astronomical phenomena
which later on were studied by
astronomers from the different parts of the
world.

10. Here are some Galileo’s discoveries
with the aid of the telescope.
Lunar Craters
Using his telescope(8x
magnification), Galileo
confirmed that there were
mountains on the moon. Toward
the end of November 1609, he
constructed a 20x magnification
telescope which helped him
gather better lunar observations.
He also observed the craters of
the moon.

11. Moons of Jupiter
In 1610, Galileo saw
Jupiter
accompanied by
four seemingly fixed
“stars”. These fixed
stars were later on
identified as the
moons of Jupiter.
Europa
Io
Ganymede
Callisto

12. Phases of Venus
These phases refers
to the variations of
illumination observed
on the planet Venus.
These differences in
Venus’s illumination
were observed by
Galileo during his stay
in Pisa, Italy in the
latter part of 1610.

13. ▪Through a telescope,
he observed that a
portion of Venus
seemed missing and
there was a variation
in its images just
like the different
phases of the moon.

14. Sunspots
▪ These are dark spots on
the sun which are
relatively colder than
other areas in the sun.
Galileo was the one of
the first astronomers to
observe this
phenomenon. Other
astronomers thought
the sunspots are not on
the surface of the sun.
▪ It was Galileo who
proved mathematically
that these spots are
indeed on the sun’s
surface.