## (solution) Equatorial System and Star Charts Examine the rectangular star

I need help completing questions 8 and 11. I've already completed all the other questions, but I'm struggling with those two. I've attached all my answers in the PDF including the Star Charts I was required to use and label throughout the lab. I've also included the original .doc of the lab so you can access it easier. The answers for 8 and 11 only have to be a couple sentences each.

To make things convenient, I've also pasted the questions I need help with below:

8. What can you conclude about the position of the planets relative to the plane of the Earth?s orbit?
Equatorial System and Star Charts

Examine the rectangular star maps. It represents a portion of the celestial sphere as a rectangle.

Distortions occur when a 3D sphere is drawn as a flat rectangle. The distortions are severe near the top

and bottom of the map. The distortion is quite workable for most purposes in the center two-thirds of

the map. It?s similar to the rectangular maps of the Earth that grossly distort the landmasses near the

north and south poles, but work fine for the major populated areas closer toward the equator.

The line running horizontally through the center of the star map represents the celestial equator. Right

Ascension (RA) is measured along this line from right to left in units of hours and minutes. Notice the RA

scale at the bottom of the map. Declination (Dec) is measured in degrees perpendicular to the celestial

equator. The scales are on the left and right edges of the map.

Print out a copy of the star chart.

1. Find on the map the ?topmost? star of the constellation Libra.

a. What is its Right Ascension in hours and minutes? ______________

b. What is its Declination in degrees? ________________

2. The sun?s location at the first day of each season in the northern hemisphere is given in the table

below. Plot its position on the rectangular star map for each date and label it with the season.

Season

Autumn

Winter

Spring

Summer

3. RA

12h 0m

18h 0m

0h 0m or 24h 0m

6h 0m Dec

0o

-23.5o

0o

+23.5o Fill in the table below with the constellation closest to the sun?s position (that is, the

constellation the sun is ?in?).

Season

Autumn

Winter

Spring

Summer Constellation the Sun is ?in? 4. Now that the four principal seasons are plotted, imagine where the sun might be on dates

between these points. For example, what are the approximate RA and Dec of the sun on

October 22? How about May 21 and July 15?

October 22 RA: ________ Dec: ________ May 21 RA: ________ Dec: ________ July 15 RA: ________ Dec: ________ The sun always appears on the imaginary line called the ecliptic. The ecliptic can also be thought of

as tracing the plane of the Earth?s orbit.

5. Label the ecliptic on the star chart.

6. The following table lists the celestial coordinates for the major planets on September 24, 2004.

Plot the planet positions on the map and label each planet. Try to use a different color pen than

the sun positions.

Planet

Mercury

Venus

Mars

Jupiter

Saturn

7. RA

11h 32m

9h 25m

11h 56m

12h 0m

7h 50m Dec

+5o

+15o

+1o

+1o

+21o Below, fill in the constellation closest to each planet?s position on September 24, 2004:

Planet

Mercury

Venus

Mars

Jupiter

Saturn Constellation 8. What can you conclude about the position of the planets relative to the plane of the Earth?s

orbit? ______________________________________________________________________ 9. The following table lists the Moon?s coordinates at 5 day intervals for a one month period. Plot

the moon?s position on the map and label each position with the date.

Date

9/24

9/29

10/4

10/9

10/14

10/19 RA

20h 23m

0h 46m

4h 51m

9h 14m

13h 14m

18h 2m Dec

-25o

+3o

+26o

+21o

-7o

-28o 10. For each of the above dates, fill in the constellation closest to each Moon position.

Date

9/24

9/29

10/4

10/9

10/14

10/19 Constellation 11. What can you conclude about the Moon?s orbit relative to the plane of the Earth?s orbit?

________________________________________________________________________

Extra Credit (5 points)

Look up the current positions of the Moon and at least two planets and plot these for a 30-day period.

You can use a source like Astronomy Magazine or Sky and Telescope or you can use the web or the Starry

Night CD to get the data. Print out a separate star chart to do this.

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Sep 13, 2020

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