Meade LX90-ACF 10 inch User Manual - Page 16

16 IMPORTANT NOTE: Objects appear upside-down and reversed left-for-right when observed in the eyepiece when inserted directly into the (straight-through) eyepiece holder - with the diagonal prism in place, images will be right-side-up, but reversed left-for-right. This image inversion is of no consequence when observing astronomical objects and, in fact, all astronomical telescopes yield inverted images. During terrestrial observing, where a fully correctly-oriented image (right-side-up and correct left-forright) is desirable, an optional #928 45° Erecting Prism is available. See OPTIONAL ACCESSORIES, page 42. OBSERVING Observing By Moving the Telescope Manually If you wish to observe a distant land object, such as a mountain top or a bird, you can observe by merely pointing the telescope and looking through the eyepiece. 1. Loosen the telescope's R.A. lock (Pg. 7, Fig. 1, 9) and Dec. lock (Pg. 7, Fig. 1, 6). 2. Move your telescope to observe distant street signs, mountains, trees, and other structures. Use the viewfinder to to help site-in on an object. 3. Center the object with viewfinder's cross hairs and then in the telescope eyepiece. When the object is centered in your eyepiece, remember to re-tighten the R.A. and Dec. locks. 4. Practice focusing objects with the focus knob (Fig. 1, 8). 5. Once you get a feel for how your telescope moves and focuses, try to view something more challenging, like a bird or a distant moving train. NOTE: Viewing conditions vary widely from night-to-night and site-to-site. Turbulence in the air, even on an apparently clear night, can distort images. Lowpower eyepieces, such as the Super Plössl 26mm supplied with your telescope, are better suited to resolving images in poor viewing conditions. You can also observe stars and objects in the night sky using this method, but note that objects begin to slowly drift across the eyepiece field. This motion is caused by the rotation of the Earth. As you become familiar with the AutoStar handbox operation, you can counteract the drift using the automatic tracking feature in the AutoStar Setup menu (see TO TRACK AN OBJECT AUTOMATICALLY, page 18), or by using AutoStar's GO TO capabilities (see GO TO SATURN, page 21). Terrestrial Observing The LX90 is an excellent high-resolution, terrestrial (land) telescope. Viewing terrestrial objects requires looking along the Earth's surface through heat waves. These heat waves often cause degradation of image quality. Lower power eyepieces, like the Super Plössl 26mm eyepiece, magnify these heat waves less than higher power eyepieces. Therefore, lower power eyepieces provide a steadier, higher quality image. If the image is fuzzy or ill-defined, reduce to a lower power eyepiece, where the heat waves do not have such an effect on image quality. Observing in early morning hours, before the ground has built up internal heat, produces better viewing conditions than during late afternoon hours. Observing Using AutoStar's Arrow Keys You may observe land and astronomical objects using AutoStar's Arrow keys to move the telescope. 1. Tighten the Dec. and R.A. locks (Pg. 7, Fig. 1, 6 and 9). Fig. 7a and 7b: Jupiter: Examples of the right amount of magnification and too much magnification. LX90 TIPS Too Much Power? Can you ever have too much power? If the type of power you're referring to is eyepiece magnification, yes, you can! The most common mistake of the beginning observer is to "overpower" a telescope by using high magnifications which the telescope and atmospheric conditions cannot reasonably support. Keep in mind that a smaller, but bright and well-resolved image is far superior to one that is larger, but dim and poorly resolved (see Figs. 7a and 7b). Powers above 400X should be employed only under the steadiest atmospheric conditions. AutoStar can calculate the best eyepiece for you to use. Try out the "Eyepiece Calc" feature in the Utilities menu. Most observers should have three or four additional eyepieces to achieve the full range of reasonable magnifications possible with the LX90 telescopes. See OPTIONAL ACCESSORIES, page 42.