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would like to override Guide's judgment, click on the spacing desired in each column, and automatic spacing will be turned off. After having adjusted the spacing to what you think it should be, you can click "Automatic Spacing" on again, and Guide will follow your judgment when you change levels. Similarly, by default, the marking will be shown in the J2000.0 epoch. Click on the Epoch line, however, and you will be prompted to enter the new epoch for this marking. The fact that different markings can use different epochs allows you to, for example, use a J2000.0 grid with B1950.0 ticks. Also, by default, all markings are in equatorial coordinates (that is, they define spacings in RA/dec). But you do have the option of selecting ecliptic, alt/az (horizon), or galactic coordinate markings instead. Finally, you'll notice a box to select the color of the marking in question. The remaining seven items each bring up fairly simple submenus, in which only the color selection and "on/off" radio buttons are available. The only exception is the "Aperture" option. This option lets you specify the size of a circle, to be drawn superimposed at the center of the chart. In this case, the submenu lets you enter the size of this circle. This is usually used to show the apparent angular field of view of a telescope. For example, if your telescope has (with a particular eyepiece) a .74 degree field of view, you could turn the aperture on and set that size. The resulting circle would let you see how much of the sky is visible, at a given time, with that telescope/eyepiece. In entering the aperture size, you can also enter 15' for a 15 arcminute circle, or 45.3" for a 45.3 arcsecond circle. Also: when any of these objects appears on-screen, you can adjust its display by right-clicking on it, then clicking "Display". The only time it is truly necessary to go through the "Ticks, Grids, Etc." menu option is when the object type you want isn't on screen (perhaps because it is turned off.) 7g: Background dialog In the Background dialog in the Display menu you may modify the usual "white stars on a black background" appearance of the screen. There are five different types of background: "normal colors", "chart mode", "red mode", "flashlight mode", and "realistic". "Normal Colors" is the default; the background is usually black. Printouts always have black stars on white (even with color printers). "Chart Mode" switches to a white background. This was first added to support color printing. If you have a color printer, you can switch to
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