How to Change the Sky Chart's Display

Change the Field of View:

Besides changing the observing location and date/time for which the Sky Chart shows you the constellations, you can change which part of the sky is featured in the Selected View. Click on the area of the All-Sky Chart that you'd like to see in more detail. The green frame will jump to where your cursor is pointing, and the scene in the Selected View window will now show this area.

Or, click and hold down your mouse button within the green frame on the All-Sky Chart, then drag the frame around the sky. The scene in the Selected View window will change as the location of the green rectangle on the All-Sky Chart changes.

Or, click and hold down your mouse button in the rectangular Selected View window, then drag the cursor to move to another part of the sky. The green frame in the All-Sky Chart will follow your movements.

Maximize the View:

The Combined View packs a lot of information into a small amount of real estate on your computer's screen. If you click the MAXIMIZE button under the All-Sky Chart or Selected View, that field will enlarge to fill the applet's 800-by-600-pixel window. In reality, the All-Sky Chart doesn't get much bigger, because even in the Combined View it already spans almost the entire height of the window. But the Selected View enlarges severalfold. The field of view remains the same as before, but the display is much larger and more readable. Note that when the Selected View is maximized, you can still move around the sky by holding down your mouse button and dragging the cursor.

To return to the Combined View, click on the BACK TO COMBINED VIEW button in the lower right corner of the maximized view.

Customize the Display:

Click on the SHOW ADVANCED DISPLAY OPTIONS button located in the bottom left corner of the Combined View (the dual-pane screen with the circular All-Sky Chart on the right and the rectangular Selected View window at upper left). This will take you to the Advanced Display Options screen:

Click the various checkboxes on or off, depending on what you'd like to see in the All-Sky Chart and Selected View, which can be controlled independently. The Interactive Sky Chart displays the following:

• The 1,686 brightest stars down to magnitude 5.0; of course, only half of these are above your horizon at any one time. You can toggle labels on or off for 26 named stars.

• The Sun, Moon, and five naked-eye planets (Mercury, Venus, Mars, Jupiter, and Saturn); you can toggle their labels (but not their symbols) on or off. Note that due to certain limitations of the software underlying the Sky Chart applet, the Moon's phase is indicated properly, but the orientation of the terminator — the line between the illuminated and shadowed parts of the Moon's face — is not; it is always depicted as vertical.

• Selected deep-sky objects (star clusters, nebulae, and galaxies); you can toggle their symbols and labels on or off.

• Selected special sky events such as meteor showers and bright comets, if any; you can toggle their symbols and labels on or off. Note that the Sky Chart displays special sky events for the current year and only a few years into the future.

• Constellation lines and labels. In the Selected View, they're either on or off. On the All-Sky Chart, you can have no lines or labels, lines only, or lines and labels. In the latter case, a name shows up only when your cursor moves over a constellation; at the same time, the constellation lines become highlighted.

• Buildings and trees are shown along the horizon in the Selected View. Sometimes they block celestial objects of interest that are low in the sky. If that happens, remove them by unchecking the appropriate box.

The RESTORE DEFAULT button resets any changes you've made to the chart's original settings. The CANCEL button returns you to the Combined View without changing any of the settings.