C. The Planets
The planets don’t stay put like the stars, so to find them you should refer to Sky Calendar at our website (telescope.com), or to charts published monthly in Astronomy, Sky & Telescope, or other astronomy magazines. Venus, Mars, Jupiter, and Saturn are the brightest objects in the sky after the Sun and the Moon. Your Observer 70 is capable of showing you these planets in some detail. Other planets may be visible but will likely appear star-like. Because planets are quite small in apparent size, optional high power eyepieces are recom- mended and often needed for detailed observations. Not all the planets are generally visible at any one time.
JUPITER: The largest planet, Jupiter, is a great subject for observation. You can see the disk of the giant planet and watch the ever-changing positions of its four largest moons— Io, Callisto, Europa, and Ganymede.
SATURN: The ringed planet is a breathtaking sight when it is well positioned. The tilt angle of the rings varies over a period of many years; sometimes they are seen edge-on, while at other times they are broadside and look like giant “ears” on each side of Saturn’s disk. A steady atmosphere (good see- ing) is necessary for a good view. You will probably see a bright “star” close by, which is Saturn’s brightest moon, Titan.
VENUS: At its brightest, Venus is the most luminous object in the sky, excluding the Sun and the Moon. It is so bright that sometimes it is visible to the naked eye during full daylight! Ironically, Venus appears as a thin crescent, not a full disk, when at its peak brightness. Because it is so close to the Sun, it never wanders too far from the morning or evening horizon. No surface markings can be seen on Venus, which is always shrouded in dense clouds.
MARS: The Red Planet makes its closest approach to Earth every two years. During close approaches you’ll see a red disk, and may be able to see the polar ice cap.
D. The Stars
Stars will appear like twinkling points of light. Even powerful telescopes cannot magnify stars to appear as more than a point of light. You can, however, enjoy the different colors of the stars and locate many pretty double and multiple stars. The famous “Double Double” in the constellation Lyra and the gorgeous two color double star Albireo in Cygnus are favor- ites. Defocusing a star slightly can help bring out its color.
E. Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinating deep sky objects, including gaseous nebulas, open and glob- ular star clusters, and a variety of different types of galaxies. Most deep sky objects are very faint, so it is important that you find an observing site well away from light pollution. Take plenty of time to let your eyes adjust to the darkness. Do not expect these subjects to appear like the photographs you see in books and magazines; most will look like dim gray smudg- es. Our eyes are not sensitive enough to see color in deep sky
objects except in a few of the brightest ones. But as you become more experienced and your observing skills get sharper, you will be able to ferret out more and more subtle details and structure.
To find deep sky objects at night it is best to consult a star chart or planisphere. These guides will help you locate the brightest and best deep sky objects for viewing with your Observer 70.
Terrestrial Viewing
The Observer 70 can be used for long distance viewing over land. We recommend using an optional 45° correct-image prism diagonal instead of the included 90° mirror star diagonal. The correct-image diagonal will yield upright, non-reversed images and provide a more comfortable viewing angle.
For terrestrial viewing, it’s best to stick with low power eye- pieces that yield a magnification under 80x. At higher powers, images rapidly lose sharpness and clarity due to “heat waves” caused by Sun-heated air.
Remember to aim well clear of the Sun, unless the front of the telescope is fitted with a professionally made solar filter.
7. Care and Maintenance
If you give your telescope reasonable care, it will last a life- time. Store it in a clean, dry, dust free place, safe from rapid changes in temperature and humidity. Do not store the tele- scope outdoors, although storage in a garage or shed is OK. Small components like eyepieces and other accessories should be kept in a protective box or storage case. Keep the dust cover on the front of the telescope and on the focuser drawtube when not in use.
Your Observer 70 telescope requires very little mechanical maintenance. The optical tube is aluminum and has a smooth painted finish that is fairly scratch resistant. If a scratch does appear, it will not harm the telescope.
Cleaning Lenses
Any quality optical lens cleaning tissue and optical lens clean- ing fluid specifically designed for multi-coated optics can be used to clean the Observer 70’s objective lens (8) and the exposed lenses of your eyepieces. Never use regular glass cleaner or cleaning fluid designed for eyeglasses
Before cleaning with fluid and tissue, blow any loose particles off the lens with a blower bulb or compressed air. Then apply some cleaning fluid to a tissue, never directly on the optics. Wipe the lens gently in a circular motion, then remove any excess fluid with a fresh lens tissue. Oily fingerprints and smudges may be removed using this method. Use caution— rubbing too hard may scratch the lens. For the larger surface of the objective lens, clean only a small area at a time, using a fresh lens tissue on each area. Never reuse tissues.
