THE COSMIC EXPLORER (600-2409) Features Faxback Doc. # 33040 Please read before using this equipment. INTRODUCTION: Radio Shack welcomes you to a wonderful opportunity to explore the visible universe surrounding earth by using its Cosmic Explorer. As you see in the illustration Panel 1, our observable sky is only a very tiny part of our Home Galaxy, which is a very small part of the universe. Yet, there are a great many unsolved questions just in our starry backyard. Questions like - how many stars are there? How do stars and planets form? We hope that by using your Cosmic Explorer as a tool for expanding your knowledge and wisdom you will become a more aware cosmic observer. THE COSMIC EXPLORER FEATURES EXPLANATION OF FEATURES: The Cosmic Explorer is a 3-D STAR MAP that can be quickly set up for observing the ski on any day of the year, from anywhere on earth. For expediency, we will describe how to set up the Cosmic Explorer for an observer at about 40 degrees latitude. We select this latitude because the vast majority of Earth observers live between 10 degrees and 50 degrees NORTH latitude. Position your Cosmic Explorer so it looks like the view photo in figure 2. Don't be afraid to pick up the Star Ball for examination. The more you handle it, the easier it is to understand. IMPORTANT: Always keep the Star Seeker support rod pointed North-South while the equator is resting on the yellow support pad. For 40 degrees latitude observation, turn the Star Seeker control knob so the pivoting and gimbaled figure has its head up, toward the Zenith, which is the overhead point on the star ball. Now, let's discuss the components of the Cosmic Explorer. FEATURES FROM FIGURE 1 Star Ball: This transparent l5" sphere is carefully crafted with over 200 manufac- turing steps to create a realistic 3-D star map. All 88 recognized constellations, their names and outlines are shown. We made the surface direct reading. This means that what you see on the Star Ball for a particular date will be seen in the sky on that same night. The Star Ball is imprinted with the Equator and the Ecliptic. Note that the Star Ball consists of two hemispheres, NORTH and South. Equator: This is a great circle that divides the Star Ball into a northern starry hemisphere and a southern starry hemisphere. Notice that there are numbers printed on the Equator. Pick up the ball and trace the numbers with your Finger. You can see that the numbers start with 0^h and increase to the right, or Eastward. There are 24 of these increments (0-23). They are the hour circles of Right Ascension. Every object in the sky has two coordinates. One is the Right Ascension. It is similar to Longitude in Earth's geography. Each hour of Right Ascension is made up of 60 minutes (m) and Each minute is made up of 60 seconds(s). We will use Right Ascension for stars and planets. Imagine that there are 24 arcs on your star ball which cross the Equator at right angles. Each arc terminates in the NORTH and South poles of the star ball. The Equator is 0 degrees Declination, which increases to +90 Degrees at the North Pole and -90 Degrees at the South Pole. More on this in a later section. Sky Calendar (Ecliptic): This is another very important great circle on the Star Ball. Pick up the Star Ball and trace the Ecliptic around the sky. If you imagine a disk floating in the Star Ball with its edge aligned with the Ecliptic, then you can visualize the plane or disk our planetary system makes. The dates on the Ecliptic represent where the sun is found each day of year. We used 5^d increments so you will have to estimate the particular day you select if it falls between the 5^d increments. While Each day is important, there are four parts of the Ecliptic that are exceptional for use. These are: - September 21: Notice that this places the sun on the Equator at the 12^h mark. This is the Autumn Equinox for inhabitants of the Northern hemisphere. The sun crosses the Equator and moves South. It is in the constellation Virgo. - December 21: Note that the sun's position is as far South as it will go. It is in the constellation Scorpius. We call this the Winter Solstice and it marks the end of autumn and beginning of winter. Southern hemisphere observers see this as their Summer Solstice, marking the end of spring. - March 20: The sun crosses the Equator at 0^h Right Ascension. It has moved from Aquarius into Pisces. We call this the spring or Vernal Equinox. Keep tracing the sun's path along the Ecliptic and you will see that it reaches the its highest point where Taurus and Gemini meet. - June 20: This is the Summer Solstice. It marks the end of spring and the start of summer. The Ecliptic, and the sun, are 23.5 degrees NORTH of the Equator. During the Winter Solstice, it is 23.5 degrees South of the equator. You can check this with your Degree Scale. Lay the 0 degrees line on the equator and the 90 degrees on the North Star. Notice that the Summer solstice is at the 23.5 degrees region of the degree scale which is marked off in 5 degrees increments. Horizon Ring: This disk encircles the star globe, dividing it into the sky which is up and visible at any given time and that which is below the Horizon. Notice that the Star Seeker is always above the Horizon Ring, viewing the visible sky. If the Star Ball a bit so it is free of the three support pads. Rotate the ball westward, keeping the Equator oriented to the position indicators (EQUATOR HERE) at the W and E cardinal joints. As you do this, the stars will rise in the East and set in West. Believe it or not, the rising and setting of the stars-where they went to after crossing the western Horizon-was a great mystery to humans for thousands of years. A good part of ancient Egyptian religion rested on their fanciful theories of fast underworld with gods that controlled the heavens. More on the Horizon Ring in the other sections. Star Seeker: This gimbaled figure represents You, the observer placed on each. If you set up the Star Ball so that the North Star is straight up and the Equator is aligned with the Horizon Ring, then you have the sky set for an observer standing at Earth's North pole. Try it now! Rotate the star ball East to West. Notice that the stars below the horizon never rise for this observer. Also, for this observer, the sun is above the horizon for six months of darkness! Now, turn the ball so that the South pole, marked by the Star Seeker position knob, is straight up. This is how the sky looks for an observer at the South pole! Just the opposite of our North pole observer. Do you think there is a place where all the stars can be seen in the course of a year? If you said-0 degrees on Earth, which is the Earth's equator, you are correct. Set up the Star Ball so that the position knob for the Star Seeker rests against the underside of the Horizon Ring at the S point. The North star should be pointing at the N point on the Horizon Ring. This is how the sky looks for an Earth observer who lives in places like Ecuador, Gabon, Kenya, or Singapore and points in between. Rotate the Star Ball to the West and you can see that all of the stars are visible at one time of year or another. VIEW FROM EAST Now, what about the observer at 40 degrees North latitude. What will they see? Read on to find out how to set up the Star Ball. You should be able to figure this out yourself using the 3-D power of the Cosmic Explorer. Degree Scale and Yellow Support Pad: We made this yellow bumper so it is about 10 degrees from top to bottom as measured on your degree scale. If you position the Equator of the Star Ball on the bottom edge of the yellow pad, then the Ball will be set for an Earth observer at 40 degrees North Latitude. You can check the proper orientation of the ball another way for observers living at different latitudes by using the Degree Scale. If you position the Degree Scale as shown and rotate the Star Ball until the 40 degrees mark is straight up, then you have set up the ball for an observer at 40 degrees North Latitude. (Notice that the Equator is on the bottom of the Yellow Pad). Try this method for observers living at the latitudes shown in TABLE 1. (BR/EB 5/10/96)