If hours of right ascension are printed along the map's top or bottom, that'll set you straight.
One trick for keeping east and west straight on a celestial map is remembering that right ascension increases to the east (it rhymes). (If you looked up through the bottom of a land map of, say, the United States - as if you were at the center of a transparent Earth - it too would have east left when north was up.) The reason is simple: You look down at the ground but up at the sky. This is usually tilted at an angle.Įast on a star chart is left of north, not to the right like on a map of the ground. North (up) on a star chart is always the direction toward Polaris in the sky, no matter what part of the sky you're looking at. To keep the familiar naked-eye patterns in perspective, some people draw in the constellation stick figures with a pencil, as we've done here.ĭirections on a star chart take a little getting used to. The same stars of Gemini appear on Chart 5 of Sky Atlas 2000.0 - but at a much larger scale and almost lost in a wealth of detail, as shown above. Suppose, for instance, you've learned Gemini as it's drawn on the monthly Sky & Telescope charts, where the stars are connected to form two stick figures holding hands. Examining the sky at 50 power is almost like examining the chart with a microscope! Note the tiny size of the telescopic field, even on a large-scale chart like Sky Atlas 2000.0. The small ring shows the 1° field of an average 50x eyepiece’s view. The large wire ring shows the 5° field of a typical finderscope. How much of a star chart appears in your eyepiece? You’ll be lost until you know. These form the same, familiar constellation patterns as on a naked-eye map. But step back for a minute, squint your eyes, and look at only the brighter stars. The smaller Pocket Atlas, with stars to magnitude 7.6, is an excellent low-cost starter and all you'll ever need for binoculars or a telescope of 3-inch aperture or less.ĭetailed, zoomed-in star charts may look terribly complex at first. It covers the celestial sphere in 26 big charts that plot a total of 81,000 stars (to as faint as magnitude 8.5) and 2,700 other objects. Using A Star Chart at the TelescopeĪ standard atlas for serious telescope users is Sky Atlas 2000.0 by Wil Tirion and Roger W.
In addition to a wide-scale constellation star chart, a telescope user needs a more detailed, magnified sky atlas in order to locate specific points of interest. If you don't know where Japan or England are, you need to learn.īut once you've found England on a world map, it's not much good for getting you to a particular street address in Tunbridge Wells. Think of your all-sky star chart as like a map of the world, and the constellations as countries. An all-sky constellation star chart (such as the evening chart in the center of Sky & Telescope every month) will get you started. Click for larger view.īy the time you set out into the night with a telescope, you should know the constellations well enough to find your way around the sky. Amid swarms of details on Sky Atlas 2000.0, the naked-eye stars of Gemini are connected here to form their familiar stick figures.
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