Seed Question: When you look up into a beautiful starry sky, what is the apparent shape of the heavens? Imagine you are lying on your back, far from city lights with an unobstructed view of the sky for hours. Where does this shape come from?

Exploration: Write kinda small…

What are the apparent daily motions of the Sun, Moon and stars? They all appear to rise in the ________, move across the sky in a giant arc and set in the _________.

What is the apparent annual motion of the Sun against the stars? In other words, if you could see the Sun against the starry background which direction would the Sun move over the course of a year? The Sun would move toward the ________, along the ecliptic.

Find the Sun’s position on your star map for today, September 8, 2020. Pencil it in on your map and put an arrow on it to indicate the Sun’s annual direction of motion.

Tonight on September 8, 2020 the Moon is located at an RA of 3h 22m and a DEC of 15o. Pencil the moon in on your star map. Is the moon on the ecliptic? If not is it above or below the ecliptic?

What time will the Moon rise for you? Show your work. Hint: Find your meridian at 10 pm on your map. What is the RA of rising stars? How much longer until the Moon rises?

Can you estimate the approximate phase of the Moon? Hint: When the Sun and Moon are twelve hours apart, you have a full Moon, 100% illumination. When the Sun and Moon are six hours apart, you have a quarter Moon, 50% illumination. How many hours apart are the Sun and Moon tonight? Based on this, about how much of the Moon do you see illuminated? Sketch it. Shade in the dark part of the Moon.

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Movement in the Heavens

Big Idea: Imagine a fixed spherical Earth centered on the inside of a much larger, giant Celestial Sphere that rotates on its axis. Tape in the Celestial Sphere Graphic from your Starter Kit after trimming it with scissors.

Each day the Sun, Moon and stars all appear to rise in the east and set in the west. Over the course of a year, the Sun appears to drift eastward relative to the stars which are fixed to the Celestial Sphere.

Discussion: ?

Right Ascension

Declination

AriesEcliptic

The Celestial Sphere Ptolemaic System (150 AD)

Celestial Equator

-90o

-60o

-30o

CapricornusSagittarius

Gemini

Taurus

PiscesAquarius0h

+90o (North Celestial Pole)

+60o

+30o

23.5o tilt

8h 16h 14h 12h

18h 20h 22h

6h

4h 2h

0o

Period of Rotation of Solar Sphere is 1 year: (1 degree to the east each day )

Period of Rotation of Celestial Sphere is 23 h 56 m

EARTH

SUN

Polaris (North Star)

Virgo

Scorpius

10h

Cancer

Leo

Libra