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It is therefore useful for meteor observers; draw the paths of meteors on this chart, and they will appear as straight lines emerging from a single point (the radiant). Equidistant projection is true in distances and azimuths from the center of the chart. It is mostly used for terrestrial charts; short-wave radio amateurs like its use. The Mercator, Peters, Miller, and "simple" projections are almost never used for sky charts. They are all cylindrical projections, in which lines of latitude are projected as parallel horizontal lines and lines of longitude are projected as parallel vertical lines. (For a sky chart, read "lines of declination and RA", or in alt/az coordinates, "lines of altitude and azimuth.") The price for this is that the north and south poles (for sky charts, read "near the celestial poles") become extremely distorted. This isn't such a big deal for charts of the earth, where people are not too concerned about the poles. But people look at the celestial poles all the time. The Mercator projection preserves shapes. But areas are greatly magnified near the poles. The Peters projection has the reverse problem: areas are preserved accurately, but shapes are compressed or stretched. The Miller projection and "simple" projections are compromises, neither preserving shape or area, but not distorting area as badly as Mercator or shape as badly as Peters. The Toolbar dialog shows a list of all functions that can appear on the toolbar. You can highlight a range of them using the mouse, and then select "On" or "Off" to turn all highlighted items on or off. You can also just double-click an option to toggle it. You can use the "Show Toolbar" checkbox to suppress display of the toolbar, and you can click OK to confirm your changes or Cancel to reject them. By default, Guide shows a "reasonable" sample of functions on the toolbar. Buttons are provided for the most commonly used zoom levels (1, 4, 7, and 10). Buttons are provided to print, to go to a planet, to find a point on the horizon, to go into the Time Dialog, to go to a "full horizon" view (180 degrees wide centered at the zenith), to use the "data shown" dialog (page 19), and to use the Animation dialog (page 46). Probably almost everyone will have a different set of "most commonly used functions", and therefore, a different toolbar. The Toolbar dialog also provides a "Max menu length" option. This defaults to 99, but if you set it to (for example) 3, then the menu options on the top line will be abbreviated to three letters in length. "Settings" will become "Set", for example. The main advantage of this is that it can allow you to fit more toolbar buttons onto the top line. (If too many buttons are selected, the excess simply forms a second or third row of toolbar buttons. But such extra rows cut into the chart area.) Finally, you can select a "Use Large Buttons" check-box. The
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