TELESCOPE BASICS MANUAL
TABLE OF CONTENTS Telescope Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Eyepieces & Magnification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Notes on the Use of High Magnification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TELESCOPE BASICS EYEPIECES & MAGNIFICATION Your telescope comes with eyepieces of different focal lengths. Eyepieces allow you to view a magnified image in your telescope. The smaller the focal length of the eyepiece, the more magnification you will get with your telescope. High power eyepieces make things appear much closer, but have a narrower field of view, meaning you see a smaller amount of sky. This can make it more difficult to locate small objects, such as planets.
FOCUSING In order to see the sharpest image possible, you need to focus the eyepiece. Focus will depend on many factors, such as distance to your target and the eyepiece you are using, but can also depend on the person looking through the telescope. While looking through the eyepiece, slowly turn the focusing knobs located below the eyepiece at the base of the focuser. You should see the image go from blurry to sharp. If you keep turning the knob and pass the focus point, the image will become blurry again.
IMAGE ORIENTATION If you have an astronomical refracting telescope and you were to insert an eyepiece directly into the telescope’s focuser, you would see an image that was upside down and mirror reversed. Because observing straight through the telescope can be difficult to use when looking directly overhead, astronomers use a mirror diagonal to make the eyepiece more accessible. The mirror in the diagonal also flips the image so that it is correctly oriented up and down.
WHAT TO EXPECT WITH YOUR NEW TELESCOPE APPARENT MOTION OF THE SKY Unlike fixed targets on the ground, astronomical targets move across the sky. This is caused by Earth’s rotation. When you observe a celestial target in your telescope, such as the Moon or planets, it will appear to slowly drift across the field of view of your eyepiece. The higher the magnification of your eyepiece, the faster the object will appear to drift.
Here are some suggestions on where to start in order of brightness: The Moon Your telescope will reveal excellent detail on the Moon. Try observing the “terminator,” the line of darkness on the edge of the Moon’s disk. Observing along the terminator provides the best detail of craters and other surface features. Try your higher-power eyepiece to see the Moon up close. The Planets Saturn and Jupiter are the best planets to observe.
TIPS FOR ASTRONOMICAL OBSERVING SELECTING AN OBSERVING SITE If you are going to be observing deep-sky objects, such as galaxies and nebulae, you should consider traveling to a dark sky site away from city lights and upwind of any major source of air pollution, with a relatively unobstructed view of the horizon. Always choose as high an elevation as possible to lower the effects of atmospheric instability and ensure that you are above any ground fog.
PRACTICE WHAT YOU HAVE LEARNED: OBSERVING THE PLANETS There are five planets that are visible to the naked eye - Mercury, Venus, Mars, Jupiter and Saturn. To the unaided eye, these planets will look similar to stars. Uranus and Neptune are too faint to see with the unaided eye, but in a telescope they will appears as slightly bloated stars. Planets change positions against the background stars on a daily basis. Don’t fear, though.
OBSERVING JUPITER Jupiter and Saturn are, without a doubt, the most beautiful planets to view in any telescope. We’ll look at them in more detail. Jupiter is the largest planet in the solar system. It has a very thick atmosphere of gas, but has no discernible solid surface. When we view Jupiter, we can only see the outer layers of its atmosphere, but there are still many wonders to see. When you look at Jupiter through a telescope, the first thing you’ll notice is its size. Jupiter is definitely not a star.
OBSERVING SATURN Saturn is the second largest planet and a gas giant similar to Jupiter. The planet appears yellowish due to its ammonia-rich upper atmosphere. Like Jupiter, Saturn has very high equatorial winds that can reach 1100 miles per hour (1800 km/h), but it lacks the contrasting dark color bands seen on Jupiter. Sometimes large storms can appear as white spots but can dissipate quickly. The main thing you notice when you look at Saturn for the first time is its incredible ring system.
HOW TO FIND DEEP-SKY OBJECTS You have now viewed the Moon and planets. It’s time to take the next step on your journey to the cosmos and look for your first objects beyond our Solar System. DEEP-SKY OBSERVING EQUIPMENT Red Flashlight This is an essential tool for deep-sky astronomy for reading finder charts or star atlases.
STARHOPPING The easiest way to find your way around the sky is using a technique called “starhopping.” To get started, measure the field of view of your finderscope. Measuring the Field of View of Your Finderscope. 1. Look in the sky and locate a constellation with bright stars. You can use your planisphere to help identify it. Now find the map in your star atlas that shows this constellation. 2. C enter your finderscope on any bright star that you can recognize on the star map. 3.
PRACTICE WHAT YOU HAVE LEARNED: OBSERVING DOUBLE STARS Double Stars Double stars, or pairs of stars that appear close together in the sky, are rewarding objects to observe. In some cases, these stars are so close together that they appear to the unaided eye as single stars, but under the magnification of a telescope, they resolve into a very closely separated pair. Some of these pairs show a very striking difference in color between the stars.
PRACTICE WHAT YOU HAVE LEARNED: OBSERVING STAR CLUSTERS Star Clusters Star clusters are groups of stars that are packed into a small area. Clusters that have loosely distributed stars are called open clusters and can contain hundreds of stars. Clusters that are very tightly packed in a small area are called globular clusters, which can contain hundreds of thousands of stars. For open clusters, you should use low power eyepieces to better frame the cluster.
PRACTICE WHAT YOU HAVE LEARNED: OBSERVING NEBULAE Nebulae Nebulae are large clouds of ionized gas or dust that lie in interstellar space. They can be classified into three basic categories: Emission Nebula - These nebulae are rich in HII (pronounced H2), or ionized hydrogen. The ionized hydrogen glows as a result of high-energy photons emitted from a nearby massive star. Emission nebulae usually contain star forming regions where the gas clouds coalesce and new stars are born.
PRACTICE WHAT YOU HAVE LEARNED: OBSERVING GALAXIES Galaxies A galaxy is an immense system of millions or billions of stars along with gas and dust that are gravitationally bound together. Most galaxies range from 3,000 to 300,000 light years in diameter and are separated from each other by vast distances of millions of light years. If you have gone outside on a dark night and seen the Milky Way stretching across the sky, you are seeing the disk of our galaxy—from the inside.
STORAGE, TRANSPORTING AND MAINTENANCE Your Celestron telescope is a precision instrument and should be kept indoors when not in use. For day-to-day observing, the scope can be left fully set up. Just make sure the covers are in place to prevent dust from entering the telescope tube. Always carry the telescope from the mount and not from the telescope tube. Most beginner telescopes are the perfect size to take with you on your next camping trip.
