<< TO DO >>: Notes in ROUGH DRAFT ...

The information in these notes should not duplicate what is found under the specific objects observed during this program ... rather, these notes should supplement the objects' information with regards to the topic of this program... and provide hyperlinks to the object pages that will be used during this program:

These notes are still in DRAFT...

Stars, Stars, and More Stars

Many of the stars in the sky are found in groups. During this program we will observe a double star, open star cluster, and a galaxy as we discuss the different kinds of groups that stars are found in. Since Venus and Mars will be in the evening sky during this time, we will start the program by observing one of them.

Object List

Date    Planet  Binary  Open    Spiral
        Star    Star Cluster    Galaxy

Jan. 15 Mars    G. Aries    h & X   M 31
16  Mars    G. Aries    NGC 663 M 31

22  Venus   G. Aries    NGC 457 M 31
23  Mars    G. Aries    h & X   M 31

Feb. 12 Mars    Xi Can. NGC 663 M 81
13  Venus   Xi Can. NGC 457 M 81

19  Venus   Xi Can. h & X   M 81
20  Mars    Xi Can. M 37    M 81

Mar. 12 Mars    G. Leo  M 35    M 65
13  Venus   G. Leo  h & X   M 66

19  Mars (?)    G. Leo  M 37    M 66
 20 Mars (?)    G. Leo  M 35    M 65

VENUS


        Compared 
    Actual  to Earth

Distance From Sun (Average) 67 million miles .72 Revolution Period 225 days .62 Rotation Period 243 days retrograde
(backwards) Diameter 7500 miles .95 Mass .82 Surface Gravity .90 Surface Temperature (Average) 480oC (900oF)

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 26mm or 40mm.

2.Venus will appear bright white through the telescope. If it is too bright, use the mask that fits over the front of the telescope. No atmospheric features are visible.

3.Venus will not be a full ball when seen through the telescope. Since it orbits closer to the Sun than we do, we see it go through phases like the Moon.

ADDITIONAL VENUS INFORMATION:

1.Through the telescope, Venus is white with no surface features. This is due to its dense, cloudy atmosphere of carbon dioxide.

2.The dense atmosphere results in the greenhouse effect. Sunlight can get through the clouds but cannot get out. This produces the 900oF (480oC) surface temperatures on Venus.

3a.Radar observations show that Venus has two continent sized plateaus on its surface. Russian spacecraft that have landed on the surface show it to be covered with boulders.

3b.The Magellan spacecraft which went into orbit around Venus in August of 1990 has mapped essentially Venus' entire surface using a high resolution radar. It has found volcanoes, craters, long channels, and many other features.

3c.Magellan discovered a 2 km (1.2 mile) wide channel winding 6,800 km (4,100 miles) over the surface of Venus. This is the longest channel in the solar system.

4.The pressure on the surface of Venus is 90 times the air pressure on Earth. Because of this you would be squashed like a bug if you were on Venus.

MARS

        Compared
    Actual  to Earth

Distance From Sun (Average) 140 million miles 1.5 Revolution Period 687 days (1.88 yrs.)
Rotation Period 24 hr. 37 min. - Diameter 4200 miles .53 Mass .11 Surface Gravity .38 Surface Temperature 140 to 20oC ( 220 to 70oF)

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 26mm or 40mm.

2.Mars will appear as a reddish or orangish ball through the telescope.

3.Dark markings on the planet's surface can be seen. These are areas of the surface which are actually darker than the rest of the surface.

4.The whitish area near one edge of the planet is the southern polar cap.

ADDITIONAL MARS INFORMATION:

1.Mars was closest to Earth on January 3rd. On that date it will be 58 million miles away. Compare that to 1988 when Mars was only 36.5 million miles away.

2.Since Mars' orbit is elliptical, its distance from Earth during closest approach can vary dramatically. In 1995, Mars will be nearly 62.8 million miles away at closest approach. After 1995, Mars' closest approaches will start getting closer until in 2003 it will be less than 35 million miles away.

3.Mars goes through seasons, just like Earth, except they are twice as long because it takes Mars twice as long to orbit the Sun. It rotates on its axis once every 24 1/2 hours.

4.The polar cap is made up of two parts, an underlying layer of water ice which is covered by a layer of frozen carbon dioxide (dry ice). When spring arrives, the dry ice evaporates, leaving the water ice.

5.Mars has a very thin atmosphere of carbon dioxide. The pressure on the surface is only 1/100 the pressure on the Earth's surface or the same as the air pressure at an altitude of 100,000 feet on Earth.

6.Temperatures on Mars range from 70oF (20oC) to 220oF ( 140oC).

7.The surface of Mars has craters.

8.The largest volcanoes in the solar system are on Mars. The base of one of them, Olympus Mons, is almost as large as Kansas.

9.There are also dry river channels on Mars. The question as to what happened to the water that made them remains unanswered. The best guess is that some of it is in the polar caps, while most of it is frozen in the ground. A small amount of water may have been lost from the atmosphere.

10.Mars appears red because of iron oxide rust in the soil.

11.Mars has two tiny irregularly shaped moons. Phobos is 17 miles (28 km) by 14 miles (20 km) while Deimos is 9 miles (15 km) by 7 miles (12 km). There is a possibility that they are captured asteroids.

GAMMA ARIES
BINARY (DOUBLE) STAR


Right Ascension:     1h52m08s           Best Seen:  10/15 - 2/15
Declination:        19o10'18"           Magnitude:  3.9
Constellation:  Aries               Apparent Separation:


    Actual  Compared to

Distance    160 l.y.    --
Separation  36 billion miles    385 Earth/Sun
Actual Brightness   --  50 (Sun)
Magnitude:  4.78 / 4.83 --
Spectral Type   --  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 24mm or 40mm

2.When people look through the telescope they should see two stars next to each other. In this case the two stars should be about the same brightness.

STARS, STARS, AND MORE STARS INFORMATION:

1.A double star is simply two stars that revolve around each other much like the Earth orbits the sun.

2.Over half of the stars in the sky are double or multiple star systems. They can't be seen as individual stars because they are too far away and too close together. A good analogy is the headlights of a distant car.

3.At least one multiple star system has as many as 9 components.

4.Note that the sun is just an ordinary star.

GAMMA ARIES INFORMATION:

1.The stars have not shown a change in position angle in 300 years.

XI CANCER
BINARY (DOUBLE) STAR


Right Ascension:     8h10m46s           Best Seen:  1/15 - 5/15
Declination:        17o43'35"           Magnitude:  4.70
Constellation:  Cancer          Apparent Separation:


    Actual  Compared to

Distance    800 l.y.    --
Separation  13 billion miles    140 Earth/Sun
Actual Brightness   --  80 / 7 (Sun)
Magnitude:  --  --
Spectral Type   --  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 24mm or 40mm

2.When people look through the telescope they should see two stars next to each other. One star should be slightly brighter than the other

STARS, STARS, AND MORE STARS INFORMATION:

1.A double star is simply two stars that revolve around each other much like the Earth orbits the sun.

3.At least one multiple star system has as many as 9 components.

4.Note that the sun is just an ordinary star.

XI CANCER INFORMATION:

GAMMA LEO
BINARY (DOUBLE) STAR


Right Ascension:    10h18m34s           Best Seen:  2/15 - 7/1
Declination:        19o58'17"           Magnitude:  1.98
Constellation:  Leo             Apparent Separation:


    Actual  Compared to

Distance    90 l.y. --
Separation  12 billion miles    125 Earth/Sun
Actual Brightness   --  90 / 30 (Sun)
Magnitude:  2.14 / 3.39 --
Spectral Type   K0 III / G7 III --

Period  600 - 700 years

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 24mm or 40mm

2.When people look through the telescope they should see two stars next to each other. One star should be slightly brighter than the other

STARS, STARS, AND MORE STARS INFORMATION:

1.A double star is simply two stars that revolve around each other much like the Earth orbits the sun.

3.At least one multiple star system has as many as 9 components.

4.Note that the sun is just an ordinary star.

GAMMA LEO INFORMATION:

1.Both of these stars are yellow.

NGC 457
OPEN STAR CLUSTER



Right Ascension:     1h17m27s           Best Seen:  10/15 - 2/15
Declination:        58o12'26"           Magnitude:  7.5
Constellation:  Cassiopeia


    Actual


Distance    9,300 l.y.
Diameter    30 l.y.
Number of Stars Several Thousand
Age     --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80mm

2.Through the telescope the cluster will appear as a group of individual stars; much like sugar or salt sprinkled on a table top.

STARS, STARS, AND MORE STARS INFORMATION:

1.Open clusters contain between 100 and 200 stars.

2.They lie in the plane of the galaxy.

3.They are made up of young (newly formed) stars.

4.Most open clusters will probably dissipate after a few billion years since they are loosely bound by their mutual gravity.

5.The separation of stars is about 3 light years. In the solar neighborhood stars are 4 5 light years apart.

6.There is another kind of star cluster in our galaxy called a globular cluster. These clusters contain over 100,000 very old stars and are found above and below the plane of the galaxy. Unfortunately there are not any globular clusters that are visible during the winter.

ADDITIONAL OPEN CLUSTER INFORMATION:

1a.Star clusters are important to astronomers because they use them to test their ideas of stellar evolution. They are able to do this because all the stars in the cluster are assumed to have formed at the same time.

1b.Theories of stellar evolution are based on computer models. The computer models are based on what we know about stars and the laws of physics. One of the things these models tell us is that different stars age at different rates.

1c.To test their theories, astronomers generate models of stars that would be found in a cluster. They then compare the appearance of this model cluster with observations of a real cluster. If there are significant differences, the astronomers change the model until it matches the real cluster.

NGC 457 INFORMATION:

1.This cluster has about 100 stars brighter than 13th magnitude.

2.The average separation of the stars in the cluster is about 1 light year.

3.The total brightness of the cluster is about 10,000 times the brightness of the sun.

4.This is a young group of stars

NGC 663
OPEN STAR CLUSTER



Right Ascension:     1h44m17s           Best Seen:  10/15 - 2/15
Declination:        61o08'24"           Magnitude:  7.1
Constellation:  Cassiopeia


    Actual


Distance    2,600 l.y.
Diameter    8 l.y.
Number of Stars few hundred
Age     --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80mm

2.Through the telescope the cluster will appear as a group of individual stars; much like sugar or salt sprinkled on a table top.

STARS, STARS, AND MORE STARS INFORMATION:

1.Open clusters contain between 100 and 200 stars.

2.They lie in the plane of the galaxy.

3.They are made up of young (newly formed) stars.

4.Most open clusters will probably dissipate after a few billion years since they are loosely bound by their mutual gravity.

5.The separation of stars is about 3 light years. In the solar neighborhood stars are 4 5 light years apart.

ADDITIONAL OPEN CLUSTER INFORMATION:

NGC 663 INFORMATION:

h and X PERSI
OPEN STAR CLUSTER



Right Ascension:     2h19m24s           Best Seen:  11/1 - 3/1
Declination:        57o01'27"           Magnitude:  4.4
Constellation:  Perseus


    Actual

Distance    7,400 l.y.
Diameter    70 l.y. (each)
Number of Stars few thousand 
Age     ~1 million years

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80mm

2.Through the large telescope only one of the clusters can be seen at a time. It will appear as a group of individual stars; much like sugar or salt sprinkled on a table top.

STARS, STARS, AND MORE STARS INFORMATION:

1.Open clusters contain between 100 and 200 stars.

2.They lie in the plane of the galaxy.

3.They are made up of young (newly formed) stars.

4.Most open clusters will probably dissipate after a few billion years since they are loosely bound by their mutual gravity.

5.The separation of stars is about 3 light years. In the solar neighborhood stars are 4 5 light years apart.

ADDITIONAL OPEN CLUSTER INFORMATION:

h and X PERSI INFORMATION:

1.The cluster h (NGC 869) is the younger of the two. It is possibly one of the youngest clusters known. (Only NGC 2362 in Canis Major may be younger.)

2.X (NGC 884) may be 1,000 light years farther away and 5 million years older than h.

3.The combined mass of the clusters is about 5,000 solar masses. They have a total luminosity of 200,000 times that of the sun.

M35
OPEN STAR CLUSTER



Right Ascension:     6h07m12s           Best Seen:  12/15 - 5/1
Declination:        24o20'28"           Magnitude:  5.3
Constellation:  Gemini


    Actual

Distance    2,700 l.y.
Diameter    30 l.y.
Number of Stars ~300
Age     --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80mm

2.Through the telescope the cluster will appear as a group of individual stars; much like sugar or salt sprinkled on a table top.

STARS, STARS, AND MORE STARS INFORMATION:

1.Open clusters contain between 100 and 200 stars.

2.They lie in the plane of the galaxy.

3.They are made up of young (newly formed) stars.

4.Most open clusters will probably dissipate after a few billion years since they are loosely bound by their mutual gravity.

5.The separation of stars is about 3 light years. In the solar neighborhood stars are 4 5 light years apart.

ADDITIONAL OPEN CLUSTER INFORMATION:

M35 INFORMATION:

1.The average distance between stars in this cluster is about 1.5 light years.

2.The luminosity of this cluster is 2,500 times the sun's luminosity

M37
OPEN STAR CLUSTER



Right Ascension:     5h51m17s           Best Seen:  12/1 - 5/1
Declination:        32o34'02"           Magnitude:  6.2
Constellation:  Auriga


    Actual

Distance    4,600 l.y.
Diameter    25 l.y.
Number of Stars 500
Age     200 million years

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80mm

2.Through the telescope the cluster will appear as a group of individual stars; much like sugar or salt sprinkled on a table top.

STARS, STARS, AND MORE STARS INFORMATION:

1.Open clusters contain between 100 and 200 stars.

2.They lie in the plane of the galaxy.

3.They are made up of young (newly formed) stars.

4.Most open clusters will probably dissipate after a few billion years since they are loosely bound by their mutual gravity.

5.The separation of stars is about 3 light years. In the solar neighborhood stars are 4 5 light years apart.

ADDITIONAL OPEN CLUSTER INFORMATION:

M37 INFORMATION:

1.Average separation of stars in this cluster is about 1 light year.

2.The total luminosity of this cluster is 2,500 times the luminosity of the sun. Hence there are a number of bright stars in this cluster.

M 31
SPIRAL GALAXY


Right Ascension:     0h42m01s           Best Seen:  9/1 - 2/15
Declination:        41o08'05"           Magnitude:  4.88.7
Constellation:  Andromeda


    Actual  Compared to
        Milky Way

Distance    2.2 million l.y.    --
Diameter    110-180 thousand l.y.   ~1.5
Mass    400 billion suns    --
Brightness  11 billion suns
Galactic Type   Sb  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 80 mm

2.When people look through the telescope they should see a fuzzy patch of light. In fact the galaxy is so large that all of it cannot fit in the field of view. This is the galaxy.

3.If they are having trouble seeing it, have them look at a star near the edge of the field, then look back to the center out of the corner of their eye.

4.The view through the telescope will not look like photographs of galaxies they may have seen. A photograph of a galaxy may have an exposure of many hours. This long exposure brings out spiral arms and other details. Our eyes allow the light to collect for only about 1/30 of a second before they refresh themselves and start over again.

STARS, STARS, AND MORE STARS INFORMATION:

1.The average spiral galaxy contains about 100 billion stars.

2.Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.

3.The disk of a typical spiral galaxy is about 100,000 light years across and 2000 light years thick. The spherical central bulge is about 10,000 light years in diameter and the halo is over 100,000 light years across.

4.Different generations of stars can be found in each of these three regions: second generation or newly formed stars are found in the disk; first generation or old stars are found in the halo; both generations are found in the central bulge.

5.Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.

6.The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M 31 INFORMATION:

1.This galaxy is the famous Andromeda galaxy.

2.This galaxy is a member of the local group.

3.It is surrounded by about 140 globular clusters.

4.The nucleus rotates in about 11 million years. The outer portions of the galaxy rotate in 100 to 200 million years.

M 81
SPIRAL GALAXY


Right Ascension:     9h53m26s           Best Seen:  2/1 - 6/15
Declination:        69o12'03"           Magnitude:  7.9
Constellation:  Ursa Major


    Actual  Compared to
        Milky Way

Distance    7 million l.y.  --
Diameter    160 thousand l.y.   1.6
Mass    250 billion suns    --
Brightness  20 billion suns
Galactic Type   Sb  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80 mm

2.When people look through the telescope they should see a fuzzy patch of light. This is the galaxy. If they are having trouble seeing it, have them look at a star near the edge of the field and them look back to the center out of the corner of their eye.

3.The view through the telescope will not look like photographs of galaxies they may have seen. A photograph of a galaxy may have an exposure of many hours. This long exposure brings out spiral arms and other details. Our eyes allow the light to collect for only about 1/30 of a second before they refresh themselves and start over again.

STARS, STARS, AND MORE STARS INFORMATION:

1.The average spiral galaxy contains about 100 billion stars.

2.Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.

5.Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.

6.The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M81 INFORMATION:

M 65
SPIRAL GALAXY


Right Ascension:    11h17m35s           Best Seen:  3/1 - 7/1
Declination:        13o15'36"           Magnitude:  9.3
Constellation:  Leo

    Actual  Compared to
        Milky Way

Distance    29 - 38 million l.y.    --
Diameter    60 thousand l.y.    2.6
Mass    --  --
Brightness  20 billion sun  --
Galactic Type   Sb  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm or 80 mm

STARS, STARS, AND MORE STARS INFORMATION:

1.The average spiral galaxy contains about 100 billion stars.

2.Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.

5.Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.

6.The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M65 INFORMATION:

1.M65 and M66 are about 180,000 light years away from each other.

M 66
SPIRAL GALAXY


Right Ascension:    11h18m53s           Best Seen:  3/1 - 7/1
Declination:        13o09'35"           Magnitude:  8.4
Constellation:  Leo

    Actual  Compared to
        Milky Way

Distance    29 - 38 million l.y.    --
Diameter    50 thousand l.y.    .5
Mass    --  --
Brightness  20 billion sun  --
Galactic Type   Sb  --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

1.Recommended eyepiece: 40mm.

STARS, STARS, AND MORE STARS INFORMATION:

1.The average spiral galaxy contains about 100 billion stars.

2.Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.

5.Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.

6.The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M66 INFORMATION:

1.M65 and M66 are about 180,000 light years away from each other.

---

Spring version:

Stars, Stars, and More Stars

Many of the stars in the sky are found in groups. During this program we will observe, a binary star, globular star cluster, and a galaxy as we discuss the different kinds of groups that stars are found in. Since Venus and Jupiter will be in the evening sky during this time, we will start the program by observing one of them.

Stars, Stars, and More Stars
Object List

Date
Planet
Binary Star Globular Star Cluster
Spiral Galaxy

April 26
Jupiter γ Leo
M 3 M 51

27
Jupiter γ Leo
M 3 M 81

May 3 Jupiter γ Leo
M 3 M 81

4
Jupiter γ Leo
M 3 M 51

10
Jupiter γ Leo
M 3 M 51

11
Jupiter γ Leo
M 3 M 81

31
Venus
γ Leo
M 3 M 81

June 1
Venus
γ Leo
M 3 M 51

7
Venus
γ Leo
M 3 M 51

8
Venus
γ Leo
M 3 M 81

JUPITER   PLANET

Actual  Compared
to Earth

Distance From Sun (Average) 480 million miles 5.2 Revolution Period 11.9 years
Rotation Period 9 hr. 50 min.
Diameter equatorial 86,000 miles 11.3 Diameter polar 83,800 miles 10.6 Mass 318 Surface Gravity 2.64 Temperature at Cloud Tops 110oC ( 166oF)

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 26mm or 40mm
Jupiter will appear as a bright white ball through the telescope. If it is too bright, use the mask that fits over the front of the telescope.
Through the telescope Jupiter will appear as a bright white ball with at least two brown belts. (When the seeing cooperates, a number of brown belts can often be seen.) The different colors refer to different layers of clouds in Jupiter's atmosphere.
Up to four of Jupiter's many moons can also be seen. These four moons, which usually lie in a line, are referred to as the Galilean moons.

STARS, STARS, AND MORE STARS INFORMATION:

Jupiter does not fit into this program theme. We are observing it because it is in the sky and it gives the sky sometime to get dark.

ADDITIONAL JUPITER INFORMATION:

Jupiter is a large ball of hydrogen and helium gas. This is the same material that makes up the Sun. In fact if Jupiter had 100 times more material (hydrogen and helium) it would have become a star.
Jupiter has three cloud layers. The top layer is white (ammonia), the middle layer is brown (ammonium hydrosulfide), and the lowest layer is blue (water). The brown belts can only be seen through holes in the white cloud layer. Since the ability to see the blue clouds requires holes in both the white and brown cloud layers at the same place, they are rarely seen.
The brown belts are really low pressure regions in the atmosphere similar to low pressure regions here on Earth. The reason they are stretched into bands is that Jupiter rotates once every 9 hours and 50 minutes. This rapid rotation along with Jupiter's larger size means the cloud tops on Jupiter are moving at a speed of over 28,000 miles per hour compared with only 1,000 miles per hour here on Earth.
The Great Red Spot has not been prominent for the last few years. It is a cloud feature, between one and three times the diameter of Earth, that is similar to a hurricane, except that it is an area of high pressure instead of low pressure. The red spot extends about 10 km (6 miles) above the white layer of clouds.
Jupiter’s ring is much narrower and fainter than Saturn’s and thus cannot be seen from Earth
The material that forms Jupiter’s ring comes from the dust that is generated by micrometeorite impacts with Jupiter’s small, inner moons.

JUPITER GALILEAN SATELLITES

Distance from Compared Revolution Diameter Diameter Jupiter to Earth Period (miles) Compared (miles)/ Moon (days) to Moon

Io 256,000 1.07 1.8 2250 1.05 Europa 416,000 1.7 3.6 1900 .90 Ganymede 663,000 2.8 7.2 3300 1.5 Callisto 1.2 million 4.9 16.7 3000 1.40

STARS, STARS, AND MORE STARS INFORMATION:

Jupiter does not fit into this program theme. We are observing it because it is in the sky and it gives the sky sometime to get dark.

GENERAL INFORMATION:

1a. Io is one of only two objects in the solar system known to have active volcanoes. (Earth is the other one. Neptune's moon Triton has liquid nitrogen geysers, not volcanoes, on its surface.)

1b. These volcanoes spew out sulfur and sulfur dioxide at a rate of 10 thousand tons per second enough to cover Io with 35 feet (10 meters) of material each million years. Any craters that were on Io have long since been filled in.

1c. The sulfur compounds spewed out by the volcanoes produce a variety of reds, oranges, browns, and whites. As a result, the surface of Io is very colorful. One astronomer was heard to remark when he saw the first pictures of Io that he had seen better looking pizzas.

1d. During several close flybys of Io, the Galileo spacecraft has confirmed that Io is the most volcanic body in the solar system, with more than 100 erupting volcanoes, gigantic lava flows, and lava lakes.

1d. The gravity of Jupiter and Europa and Ganymede squeeze Io, causing its surface to stretch and compress hundreds of meters and to heat up. This heat powers the volcanoes.

1f. Mountains on Io are much taller than Earth’s largest mountains (Everest is 29,035 feet), towering up to 52,000 feet (16 kilometers) high. Paradoxically, they do not appear to be volcanoes. Scientists are not sure how the mountains form, but new Galileo images provide a fascinating picture of how they die. Concentric ridges covering the mountains surrounding plateaus offer evidence that the mountains generate landslides as they collapse under the force of gravity. The ridges bear a striking resemblance to the rugged terrain surrounding Olympus Mons on Mars.

1g. Io doesn’t have any craters because they’ve all been filled in by the lava from volcanoes.

2a. The Galileo Spacecraft has shown that Europa looks like broken glass that has been repaired by an icy glue oozing from below. Low ridges, straight and curved, criss-cross the surface. Flows and fractures, pits and frozen “puddles” – all hint at a unique geologic history.

2b. Small blocks of crust are thought to float like icebergs over an invisible sea. Some blocks are tilted, other rotated out of place. Dark bands of ice and rock spread outward from central ridges.

2c. This was caused by a gravitational tug-of-war. Europa is pulled in different directions by Jupiter of the planet’s other moons. Over the course of one day on Europa, it stretches and compresses up to several tens of meters. The flexing of Europa’s surface cracks its brittle crust.

2d. What happens when the crust fractures is unknown. The process may be slow and steady, advancing only centimeters at a time – or, it may cause ice volcanoes or geysers to erupt violently, showering the surface with material from below.

2e. Possessing more water than the total amount found on Earth, Europa appears to have a salty ocean beneath its surface.

Ganymede is the largest moon in the solar system. It is about half ice and half rock.
Callisto, like Ganymede is half ice and half rock. There are so many craters on its surface that old craters would have to be destroyed by any new ones.
Ganymede and Callisto are both larger than the planets Mercury and Pluto. If they were going around the sun instead of Jupiter they would be called planets.
During 2000, 11 new moons orbiting Jupiter were discovered. (One had been seen previously but was lost.) Jupiter is now known to have at least 28 moons.

IDENTIFYING JUPITER’S MOONS

The table below shows the positions of Jupiter’s moons during The Discoveries of Galileo program as seen through an inverting telescope. Don't forget use of a star diagonal confuses the issue.

April 26
April 27

May 3
May 4

May 10
May 11

VENUS


    Compared 
Actual  to Earth

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 26mm or 40mm.
Venus will appear bright white through the telescope. If it is too bright, use the mask that fits over the front of the telescope. No atmospheric features are visible.
Venus will not be a full ball when seen through the telescope. Since it orbits closer to the Sun than we do, we see it go through phases like the Moon.

STARS, STARS, AND MORE STARS INFORMATION:

Venus not fit into this program theme. We are observing it because it is in the sky and it gives the sky sometime to get dark.

ADDITIONAL VENUS INFORMATION:

Through the telescope, Venus is white with no surface features. This is due to its dense, cloudy atmosphere of carbon dioxide.
The dense atmosphere results in the greenhouse effect. Sunlight can get through the clouds but cannot get out. This produces the 900oF (480oC) surface temperatures on Venus.

3a. Radar observations show that Venus has two continent sized plateaus on its surface. Russian spacecraft that have landed on the surface show it to be covered with boulders.

3b. The Magellan spacecraft which went into orbit around Venus in August of 1990 has mapped essentially Venus' entire surface using a high resolution radar. It has found volcanoes, craters, long channels, and many other features.

3c. Magellan discovered a 2 km (1.2 mile) wide channel winding 6,800 km (4,100 miles) over the surface of Venus. This is the longest channel in the solar system. (For comparison, the Nile river is nearly as long at a length of over 6,600 km or 4,090 miles.)

The pressure on the surface of Venus is 90 times the air pressure on Earth. Because of this you would be squashed like a bug if you were on Venus.

GAMMA LEO BINARY STAR

Right Ascension: 10h18m34s Best Seen: 2/15 - 7/1 Declination: 19o58'17" Magnitude: 1.98 Constellation: Leo Apparent Separation:

Computer File: Gammaleo

Actual  Compared to

Distance 90 l.y. -- Separation 12 billion miles 125 Earth/Sun Actual Brightness -- 90 / 30 (Sun) Magnitude: 2.14 / 3.39 -- Spectral Type K0 III / G7 III --

Period 600 - 700 years

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 24mm or 40mm
When people look through the telescope they should see two stars next to each other. One star should be slightly brighter than the other

STARS, STARS, AND MORE STARS INFORMATION:

A binary star is simply two stars that revolve around each other much like the Earth orbits the sun.
Many of the stars in the sky are binary or multiple star systems. They can't be seen as individual stars because they are too far away and too close together. A good analogy is the headlights of a distant car.
Note that the sun is just an ordinary star.

GAMMA LEO INFORMATION:

Both of these stars are yellow.

M 3 GLOBULAR STAR CLUSTER

Right Ascension: 13h41m00s Best Seen: 4/1 - 9/1 Declination: 28o31'24" Magnitude: 4.5 Constellation: Canes Venatici

Actual

Distance 35,000 - 40,000 l.y. Diameter 220 l.y. Total Luminosity 160,000 Solar Lum. Number of Stars 500,000 Age 10 billion years

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 40mm or 80mm
Through the telescope the cluster will appear similar to a pile of sugar or salt on a table.

STARS, STARS, AND MORE STARS INFORMATION:

Globular clusters are found in the galactic halo - above and below the plane of the Milky Way.
These clusters contain about 100,000 stars.
The cluster has kept its shape for 10 to 13 billion years and will continue to do so for another 15 to 20 billion years.
There are about 120 globular clusters associated with our galaxy.
There is another type of cluster found in our galaxy, called an open cluster. Open clusters are made up of a few hundred young stars and are found in the plane of the galaxy.

ADDITIONAL GLOBULAR CLUSTER INFORMATION:

1a. Star clusters are important to astronomers because they use them to test their ideas of stellar evolution. They are able to do this because all the stars in the cluster are assumed to have formed at the same time.

1b. Theories of stellar evolution are based on computer models. The computer models are based on what we know about stars and the laws of physics. One of the things these models tell us is that different stars age at different rates.

1c. To test their theories, astronomers generate models of stars that would be found in a cluster. They then compare the appearance of this model cluster with observations of a real cluster. If there are significant differences, the astronomers change the model until it matches the real cluster.

M 3 INFORMATION:

This is one of the three brightest globular clusters in the northern sky. M13 and M5 are the other two.
Integrated spectral type: F7.
This cluster is approaching us with a velocity of 90 miles per second.

M 81 SPIRAL GALAXY

Right Ascension: 9h53m26s Best Seen: 2/1 - 6/15 Declination: 69o12'03" Magnitude: 7.9 Constellation: Ursa Major

Actual  Compared to
    Milky Way

Distance 7 million l.y. -- Diameter 160 thousand l.y. 1.6 Mass 250 billion suns -- Brightness 20 billion suns Galactic Type Sb --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 40mm or 80 mm
When people look through the telescope they should see a fuzzy patch of light. This is the galaxy. If they are having trouble seeing it, have them look at a star near the edge of the field and them look back to the center out of the corner of their eye.
The view through the telescope will not look like photographs of galaxies they may have seen. A photograph of a galaxy may have an exposure of many hours. This long exposure brings out spiral arms and other details. Our eyes allow the light to collect for only about 1/30 of a second before they refresh themselves and start over again.

STARS, STARS, AND MORE STARS INFORMATION:

The average spiral galaxy contains about 100 billion stars.
Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.
The disk of a typical spiral galaxy is about 100,000 light years across and 2000 light years thick. The spherical central bulge is about 10,000 light years in diameter and the halo is over 100,000 light years across.
Different generations of stars can be found in each of these three regions: second generation or newly formed stars are found in the disk; first generation or old stars are found in the halo; both generations are found in the central bulge.
Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.
The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M81 INFORMATION:

M 51
SPIRAL GALAXY

Right Ascension: 13h28m47s Best Seen: 3/1 - 9/15 Declination: 47o20'25" Magnitude: 8.1 Constellation: Canis Venatici

Computer File: M51

Actual  Compared to
    Milky Way

Distance 14 million l.y. -- Diameter 260 thousand l.y. 2.6 Mass 60 billion suns -- Brightness 10 billion sun -- Galactic Type Sc --

WHAT TO LOOK FOR THROUGH THE TELESCOPE:

Recommended eyepiece: 40mm or 80 mm
When people look through the telescope they should see a fuzzy patch of light. This is the galaxy. If they are having trouble seeing it, have them look at a star near the edge of the field and them look back to the center out of the corner of their eye.
The view through the telescope will not look like photographs of galaxies they may have seen. A photograph of a galaxy may have an exposure of many hours. This long exposure brings out spiral arms and other details. Our eyes allow the light to collect for only about 1/30 of a second before they refresh themselves and start over again.
This galaxy is "face-on". As a result visitors may be able to see some spiral structure. The companion to the main galaxy can also be seen.

STARS, STARS, AND MORE STARS INFORMATION:

The average spiral galaxy contains about 100 billion stars.
Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.
The disk of a typical spiral galaxy is about 100,000 light years across and 2000 light years thick. The spherical central bulge is about 10,000 light years in diameter and the halo is over 100,000 light years across.
Different generations of stars can be found in each of these three regions: second generation or newly formed stars are found in the disk; first generation or old stars are found in the halo; both generations are found in the central bulge.
Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.
The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

M51 INFORMATION:

The Hubble Space Telescope has taken photographs of the core of M51 which reveal a dark "X" at the exact center of the galaxy.
The "X" may mark the location of a black hole which may have a mass equivalent to one hundred million stars like the Sun.
The darkest bar of the "X" may be an edge-on accretion disk, 100 light-years in diameter, surrounding the central black hole.
The second bar of the "X" could be rotating clouds of gas and dust near the black hole.
M51 has a close companion galaxy. Material from within M51 may be falling into its central balck hole as a result of the passage of its companion.
The companion galaxy happens to be passing near the large spiral at this point in time. As a result of the passage, one of the arms is miss-shaped. This cannot be seen in the telescope but can be easily seen in a photograph.

ADDITIONAL SPIRAL GALAXY INFORMATION:

Spiral galaxies are plate shaped with a central bulge. The whole galaxy is surrounded by an invisible spherical halo of dark matter.
The disk of a typical spiral galaxy is about 100,000 light years across and 2000 light years thick. The spherical central bulge is about 10,000 light years in diameter and the halo is over 100,000 light years across.
The average spiral galaxy contains about 100 billion stars.
Different generations of stars can be found in each of these three regions: second generation or newly formed stars are found in the disk; first generation or old stars are found in the halo; both generations are found in the central bulge.
Most of the dust and gas in the galaxy is found in the disk. Almost none is seen in the halo.
The spiral pattern traces the location of current star formation. It may be caused by spiral ripples in the gas of the disk or by the effects of exploding stars (supernovae) on the gas.

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