1. Evening Classes Week One
How the Sky Moves
Presented by Oisín Creaner

3. Course Outline Week 1: The Sky Week 2: The Planets Week 3: The Stars
Week 4: History of Astronomy
Week 5: Telescopes
Week 6: Deep Sky Objects
Week 7: Cosmology
Week 8: Alien Worlds

4. Basic Equipment
Your eyes!
Binoculars
Books
Planisphere

5. Stars & Constellations The Planets (W2) Galaxies & Nebulae (W6)
What can I see?
Stars & Constellations
The Planets (W2)
Galaxies & Nebulae (W6)
The Moon and Sun (CAREFUL!)

6. a: Zenith b: Meridian c: Horizon
The night sky is like an up-turned bowl above the
astronomer’s head.
a: Zenith
b: Meridian
c: Horizon

7. The Celestial Sphere We can pretend the night sky is a sphere,
because all its stars
are so far away from
us, they don’t appear
to move at all.

8. The Celestial Sphere appears to spin
because we see it from the surface
of the spinning Earth.

9. Stars appear fixed on the Celestial Sphere.
Polaris
Note the
positions of –
The Plough
Polaris
Orion
The Plough
Orion

10. Celestial Coordinates
Declination is equivalent to latitiude and is measured in degrees.
Right Ascension is equivalent to longitude and is measured in hours, minutes and seconds.

11. Special Observation Locations

12. The View from Athlone - 53° North

13. Polaris stays in the same place –
always directly North, 53° above the horizon.

14. Where you are on the Earth’s surface determines
what constellations you can see, and how often.
Declination of
stars seen
from Athlone
Circumpolar –
90° N to 37° N
Seen sometimes –
37°N - 37°S
Never seen –
37°S - 90°S

16. The ecliptic is where the Sun is seen against
the Celestial Sphere.

17. The zodiac is a 16º wide band of sky where
the planets are seen.

18. γ The Sun crosses the celestial equator at the first
point of Aires, in the constellation Pisces.
Ecliptic γ
Cel. Equator
This is the zero-point of the RA axis (0h 0m)

19. The Sun’s movement above & below
the Celestial Equator
The track of the Sun across the Celestial Sphere
is known as the Ecliptic.

20. Precession of the Equinoxes The spinning
Earth wobbles on its axis once every 26,000 years.

21. Using A Planisphere

22. Polaris
Time
Date

23. Match the time
with the date

24. The Sky Window

25. Autumn Sky- October 10 p.m.
Since there are 12 months in the year, and 24 hours in the day, every month, an object will rise 2 hours earlier

26. Autumn Sky- Andromeda

27. Autumn Sky- Andromeda

28. Autumn Sky- Cygnus ‘The Swan’

29. Autumn Sky- Sagittarius ‘The Teapot’

30. Orion as a signpost
Auriga
Gemini
Taurus
Canis Minor
Canis Major

31. Useful websites
Thank You