# A Quick Tour of &kstars;

This chapter introduces most of the useful features of &kstars;, in the form of a guided tour.

Here's a screenshot of the &kstars; main window: Main Window

In the above screenshot, you can see the sky display centered on the constellation Taurus. Stars are displayed with realistic colors and relative brightnesses. The brightest stars have their names labeled (&eg;, Aldebaran). Saturn is visible near the center, and there are a couple dozen deep-sky objects (shown as colored symbols) throughout the region. Above the sky display, there is an information panel displaying the current time and date (left), the coordinates of the screen center (middle), and the current geographic location (right). There is a tool bar and a menu bar above the information panel. There is a status bar at the bottom of the window, which displays the name of any object you click on, and the sky coordinates of the mouse cursor.

## Where am I?

The first thing to do is to set the geographic location. By default, &kstars; assumes you are in Greenwich, UK (home of the Royal Observatory, where longitude=0 is defined). Since you are probably somewhere else, you'll want to change this.

Open the Set Location window by selecting Geographic... from the Location menu, or by pressing the Globe icon in the toolbar.

Here is a screenshot of the Set Location window: Changing the Location Set Location Window

In the upper right, there is a list of over 2000 predefined cities. You set your location by highlighting a city from this list. If your town is not in the list, you can simply choose the nearest town to you. Each city is represented in the world map as a small dot, and when a city is highlighted in the list, a red crosshairs appears on its location in the map.

It isn't practical to scroll through the full list of 2000 locations, looking for a specific city. To make searches easier, the list can be filtered by entering text in the boxes below the map. For example, in the screenshot, the text Ba appears in the City Filter box, while M has been entered in the Province Filter box, and US is in the Country Filter box. Note that all of the cities displayed in the list have city, province, and country names that begin with the entered filter strings, and that the message below the filter boxes indicates that 7 cities are matched by the filters.

The list can also be filtered by location in the map. Clicking anywhere in the world map will show only those cities within two degrees of the clicked location. At this time, you can search by name, or by location, but not both at once. In other words, when you click on the map, the name filters are ignored, and vice versa.

If you want to use the exact coordinates of your location, or if there is no predefined city near your location, you can manually define a new location using the edit boxes at the bottom of the window. You must fill in each of these boxes (except State/Province, which is optional) before you can add the location to the list of known places. &kstars; will automatically load your custom locations in future sessions. Please note, at this point, the only way to remove a custom location is to remove the appropriate line from the file `~/.kde/share/apps/kstars/mycities.dat`.

## What Time Is It?

The next thing you may want to do is change the time and/or date. When &kstars; starts up, the time is set to your computer's system clock, and the &kstars; clock is running to keep up with the real time. If you want to stop the clock, select Stop Clock from the Time menu, or simply press the Pause icon in the toolbar. You can make the clock run slower or faster than normal using the time-step spinbox in the toolbar.

You can change to any time or date by selecting Set Time... from the Time menu, or by pressing the hourglass icon in the toolbar. The Set Time window uses a standard &kde; Date Picker widget, coupled with three spinboxes for setting the hours, minutes and seconds. If you ever need to reset the clock back to the current time, just select Set Time to Now from the Time menu.

## Have a Look Around!

Now that we have the time and location set, let's have a look around. You can pan the display using the arrow keys. If you hold down the &Shift; key before panning, the scrolling speed is doubled. The display can also be panned by clicking and dragging with the mouse. Note that while the display is scrolling, not all objects are displayed. This is done to cut down on the CPU load of recomputing object positions, which makes the scrolling smoother. You can zoom in and out with the + and - keys, with the zoom in/out buttons in the toolbar, or by selecting Zoom In/Zoom Out in the View menu. Notice that as you zoom in, you can see fainter stars than at lower zoom settings.

Zoom out until you can see a green curve; this represents your local horizon. If you haven't adjusted the &kstars; configuration, the display will be solid green below the horizon, representing the solid ground of the Earth. There is also a white curve, which represents the celestial equator (an imaginary line which divides the sky into northern and southern hemispheres). There is also a tan curve, which represents the Ecliptic, the path that the Sun appears to follow across the sky over the course of a year. Therefore, the Sun is always found somewhere along the Ecliptic, and the planets are never far from it.

## Objects in the Sky

&kstars; displays thousands of objects: stars, planets, clusters, nebulae and galaxies. You can identify any object by clicking on it (its name appears in the statusbar at the bottom of the window). You can get more information about an object by right-clicking on it. A popup menu will appear, showing its name(s), object type, and links to images and information from the internet.

If you know of an additional &URL; with information or an image of the object, you can add a custom link to the object's popup menu using the Add Link... item. This opens a window in which you can enter the &URL; and the text that should appear in the popup menu. You can make sure the &URL; is correct with the Check URL button, which will test the &URL; in your web browser. Please specify whether the &URL; points to an Image, or to an HTML document! If you specify Image here, the new menu item will open the Image Viewer, not the web browser. You can also point to files on your local disk, so this feature could be used to attach observing logs or other custom information to objects in &kstars;. Your custom links are automatically loaded whenever &kstars; starts up, and they are stored in the directory `~/.kde/share/apps/kstars/`, in files `myimage_url.dat` and `myinfo_url.dat`.

You can search for named objects by clicking on the search icon in the toolbar, or by selecting Find Object... from the Location menu. The Find Object window lists all the named objects in the &kstars; database. Many objects are listed only by their catalog name (for example, NGC 3077), but some are also listed by their common name (for example, Whirlpool Galaxy). You can filter the list by name, or by object type. Highlight the desired object, and press Ok. The display will center on the object and begin tracking it. Note that if the object is below the horizon, you may not see anything except the ground. You can make the ground invisible in the Display Options window.

Object Tracking is automatically engaged whenever an object is centered in the display, either by using the Find Object window, by double-clicking on an object, or by selecting Center and Track from the right-click popup menu. You can disengage tracking by panning the display, pressing the Lock icon in the toolbar, or selecting Track Object from the Location menu.