AstronomyMerit Badge

Part 2. Covered in the cabin on Wednesday 7-Dec-2011

Review

Counselor Name: Niels RydeE-mail ryde@comcast.net

Requirements 1 – 3 and 4 in part was covered on 16-Nov-2011

Requirements 4 – 5 on 7-Dec-2011

Scouts should prepare for requirement 5b and 6

The Astronomy merit badge booklet is available in Troop 7’s library in the cabin. Many answers to the requirements can be found there.

4.a Constellations

Identify at least 10 constellations in the sky, of which at least four are in the zodiac.

All year round constellations (circumpolar) {Decl ≥90-Lat.}Ursa Major, Ursa Minor, Cassiopeia, Draco, Cepheus

SeasonalSpring Summer Autumn WinterLeo Lyra Pegasus OrionVirgo Cygnus Andromeda Canis MajorLibra Aquila Perseus GeminiCancer Scorpius Aries Auriga

Sagittarius Pisces TaurusCapricorneusAquarius

Circumpolar constellations

№ Symbol Long. Latin name English translation

1 ♈ 0° Aries The Ram

2 ♉ 30° Taurus The Bull

3 ♊ 60° Gemini The Twins

4 ♋ 90° Cancer The Crab

5 ♌ 120° Leo The Lion

6 ♍ 150° Virgo The Maiden

7 ♎ 180° Libra The Scales

8 ♏ 210° Scorpio The Scorpion

9 ♐ 240° Sagittarius The (Centaur) Archer

10 ♑ 270° Capricorn"Goat-horned" (The Sea-Goat)

11 ♒ 300° Aquarius The Water-Bearer

12 ♓ 330° Pisces The Fish

Zodiac signs

Constellations in a band (± 8 deg) around the ecliptic

4.b Name Eight Conspicuous Stars

Star Name RA h m

dec ° ’

Apparent magnitude

Alpha Canis Majoris Sirius 06 45.2 –16 43  –1.44

Alpha Bootis Arcturus 14 15.7 +19 11  –0.05

Alpha Lyrae Vega 18 36.9 +38 47 0.03 (var.)

Alpha Aurigae Capella 05 16.7 +46 00 0.08

Beta Orionis Rigel 05 14.5 –08 12 0.18 (var.)

Alpha Canis Minoris Procyon 07 39.3 +05 14 0.40

Alpha Orionis Betelgeuse 05 55.2 +07 24 0.45 (var.)

Alpha Aquilae Altair 19 50.8 +08 52 0.76 (var.)

Alpha Tauri Aldebaran 04 35.9 +16 31 0.87

Alpha Virginis Spica 13 25.2 –11 10 0.98 (var.)

Beta Geminorum Pollux 07 45.3 +28 02 1.16

Alpha Cygni Deneb 20 41.4 +45 17 1.25 (var.)

Alpha Leonis Regulus 10 08.4 +11 58 1.36

Alpha Geminorum Castor 07 34.6 +31 53 1.58b

And five with a magnitude below 1

4 c. Movement of the stars in the sky

Make two sketches of the Big Dipper. In one sketch, show the Big Dipper's orientation in the early evening sky. In another sketch, show its position several hours later. In both sketches, show the North Star and the horizon. Record the date and time each sketch was made.

6 p.m.

9 p.m.

12 a.m.

4 d. The Milky Way.

How to navigate the sky

To find your way in unfamiliar territory, we need a map and signposts.

The maps can be found in books or online. The signposts are in the sky, once you know where to look.

Start with easy to recognize patterns, such as the big dipper in the spring, or Orion in the winter and work your way outward to locate other constellations and bright stars.

Signpost in the Autumn Sky

The square of Pegasus lies high in the south at 10 p.m. in October, 8 p.m. in November, and 6 p.m. in December. The corners of the square are of only moderate brightness. They enclose a relatively large area almost entirely devoid of naked eye stars.

To the top right lies Deneb.

Between the square and polaris (north star) lies Cassiopeia (W shaped constellation).

A line drawn on top of the W and left brings you to Capella.

A line drawn downward from the right side of the square brings you to Fomalhaut, a bright star in Piscis Austrinus

Signpost in the Winter Sky

Sirius glitters due south at midnight in January, 10 p.m. in February and 8 p.m. in February. Sirius lies at the southern apex of the winter triangle, Procyon at the upper left and Betelgeuse at the upper right.

Betelgeuse marks the upper left of Orion. At the bottom right of Orion lies Rigel. Across the center runs a distinctive line of three stars comprising Orion’s Belt.

To the top right of Orion lies another prominent star, Alderbaran, which represents the eye of Taurus.

Continue the line from Orion through Aldebaran brings you to the Pleiades, a star cluster.

Above Orion, almost directly between it and the north star lies Capella.

To the top left, above the winter triangle lies Castor and Pollux, the celestial twins in the constellation Gemini.

Signpost in the Spring Sky

Start with the familiar Big Dipper which is high in the sky in early spring. The two stars the farthest away from the handle are called the pointers.

Connect a line between the pointers upward (about 5 times the distance of the pointers) brings you to Polaris (the north star). Opposite of Polaris lies Cassiopeia, the W shaped constellation.

Extend the pointers in the opposite direction (away from Polaris) brings you to the constellation Leo. This constellation is notable for its sickle-shape of stars, like a reverse question mark.

Now back to the Big Dipper. Follow the curve of the handle and you will arrive at Arcturus, one of the brightest stars in the sky. Continue the curve and you will come to Spica in the constellation Virgo.

Arcturus and Spica forms a triangle with Regulus, the brightest star in Leo.

Signpost in the Summer Sky

High in the sky, you will find three stars comprising the summer triangle. In order of decreasesing brightness, they are Vega, Altair and Deneb. Vega is the first star to appear in the summer sky as the sky darkens.

Deneb is the brightest star in the constellation Cygnus (The Swan), but is better visualized as a cross. Deneb is at the head of the cross. The foot of the cross points to Antares, which appears low in the horizon.

5 The Planets

a) List the names of the five most visible planets. Explain which ones can appear in phases similar to lunar phases and which ones cannot, and explain why.

b) Find out when each of the five most visible planets that you identified in requirement 5a will be observable in the evening sky during the next 12 months, then compile this information in the form of a chart or table. Update your chart monthly to show whether each planet will be visible during the early morning or in the evening sky.

http://www.12dstring.me.uk/fov.htm Select calculators and then planetary orbit info

Diagram shows the relative position of the plants for the date indicated below

Diagram shows the relative position of the plants for the date indicated below

Diagram shows the relative position of the plants for the date indicated below

Diagram shows the relative position of the plants for the date indicated below

Diagram shows the relative position of the plants for the date indicated below

Month Sun Mercury Venus Mars Jupiter SaturnRise Set Rise Set Rise Set Rise Set Rise Set Rise Set

15-Dec-11 7:17 16:38 5:38 15:35 9:30 18:50 23:04 12:06 13:43 3:02 2:36 13:4515-Jan-12 7:22 17:01 6:35 15:49 9:21 20:03 21:38 10:26 11:41 1:03 0:44 11:4915-Feb-12 6:56 17:37 7:22 18:07 8:39 21:09 19:19 8:21 9:48 23:16 22:40 9:4815-Mar-12 7:13 19:09 7:23 20:04 8:56 23:04 17:32 7:01 9:08 22:48 21:40 8:5215-Apr-12 6:23 19:41 5:30 17:20 8:16 23:39 15:05 4:39 7:24 21:21 19:28 6:45

15-May-12 5:46 20:11 5:15 19:00 7:14 22:45 13:35 2:49 5:47 19:58 17:19 4:4115-Jun-12 5:33 20:33 5:56 22:06 4:47 19:13 12:36 1:12 4:09 18:32 15:11 2:3615-Jul-12 5:46 20:30 7:32 21:12 3:10 17:20 11:56 23:44 2:32 17:06 13:15 0:38

15-Aug-12 6:14 19:58 4:45 18:57 2:42 17:11 11:27 22:24 0:50 15:29 11:22 22:3615-Sep-12 6:43 19:10 7:04 19:25 3:07 17:13 11:08 21:15 22:57 13:43 9:35 20:4115-Oct-12 7:13 18:22 9:09 19:08 4:01 16:55 10:57 20:22 21:00 11:46 7:54 18:5215-Nov-12 6:48 16:45 7:16 16:56 4:06 15:25 9:43 18:50 17:48 8:32 5:10 16:00

Rise and set times for the sun and the planets

Use this table to figure out requirement 5b

Study on your own6. At approximately weekly intervals, sketch the position of Venus, Mars or Jupiter in relation

to the stars. Do this for at least four weeks and at the same time of night. On your sketch, record the date and time next to the planet's position. Use your sketch to explain how planets move.