or choose from the menu:
There will come a time when you will want to repeat an observation with conditions as close to the orignal as possible. Depending on your particular needs, you will want to search in one of two ways:
Libration searches can be general, or particular to a specific object.
To begin a general libration search, click on the speed button or choose from the menu:
The following window will appear, with default settings in place:
The current values of libration and date are automatically transfered here from the main window. You can modify the libration values directly in the box, or you can move the mouse over the lunar image until you are happy with the values there. The farther from the Moon's center, the stronger the libration. If you want to return to the original values, click "Reset".
Closeness, in degrees, tells the program how similar you want the libration to be. Using the example above, a libration of -1 E/W would satisfy the criteria, but a libration of 0 would not. A visual way of thinking about it is the program would catch all the dates that fall within a circle of 2 degrees on the libration graph: 
Closeness in PA for larger librations, in degrees, tells the program to include stronger librations, but only if the position angle is similar. In the above example, librations greater than 4.3 in PA of 139-159 will be included, thus presenting limb objects at a better angle. If you do not want this, then uncheck the box.
Solar latitude closeness, in degrees, tells the program to underline those matching events when the latitude of the Sun is close to the original. Since the solar latitude varies from -1.6 to +1.6, a variation of 0.4 is a reasonable match.
In short, the more bold and underlined the output is, the better the match.
You can use the mouse to select sections of the text, as well as use the normal window commands Ctrl-A to select all, and Ctrl-C to copy to the clipboard, then paste into other documents. Programs such as Word and Wordpad will maintain the formatting.
If there are too or not enough events, you can tighten or loosen the search by changing the "closeness". If you search criteria is very tight, you will need to make the search interval shorter than a day, otherwise it is possible to skip over a match because libration can change significantly from one night to the next.
To have Lunar Calculator go to the date, single left-click anywhere on the line, then click GoTo Date on the menu bar. The libration search window will minimize (in case you want to try another date), and the new view will begin generating.
If you are studying a particular object or area of the Moon, especially near a limb, you will want to know both when it is librated into view and if it is in sunshine. Although the libration graph is useful to let you know whether the librated limb is in darkness or not, it's not the whole story. It is possible for a limb to be in darkness yet the libration is so strong that the object of interest near the limb will be in light. "Specific object libration search" will do this for you!
On the main window, right-click on the area/object, and choose "Search for good libration"
and the search window appears, with a favorable object panel top center. Adjust any values if you wish, then click "Find".
Note that the only dates shown are when the object/area is lit. Once again, to go directly to that date, click anywhere on that line, then click "GoTo Date" on the menu!
To change the these settings, enter the values you want directly in the boxes, and on exiting the program, save the configuration.
Lite users can only look forward 3 months.