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--- en:documentation:date_time [2011/09/02 18:42] – pch
+++ en:documentation:date_time [2017/02/25 22:56] (current) – [Setting the date and time manually] pch
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 ===== Time =====
-{{  en:documentation:date_time.jpg|}}
+{{  en:documentation:date_time.jpg|}}\\
-\\ \\
+\\
 With this dialog box you can set the date and time for SkyChart to use. To display a reliable chart, SkyChart needs to do many calculations which require time as a parameter. The proper date and time setting is very important to display an accurate position of the planets, comets and asteroids. The date and time is also very important to display a proper chart when you are using Alt-Az coordination grid, or when you want to check the visibility of an object in the detailed information window. You might even want to display the proper motion of stars over many years.
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 ==== Setting the date and time manually ====
-You need to **uncheck** the //Use system time// checkbox when you want to display a chart **for a date / time in the future or past**. You can set the date and time by usage of the appropriate combo boxes. SkyChart can calculate with dates in the range from -20000 to +20000 years. However, the planet positions are only properly calculated for dates from -3000 to +3000. Beware with the negative years: 1BC is the year 0 and 2BC is the year -1. Note that the entered time is the local time (legal time) of the defined observatory location. \\
+You need to **uncheck** the //Use system time// checkbox when you want to display a chart **for a date / time in the future or past**. You can set the date and time by usage of the appropriate combo boxes. SkyChart can calculate with dates in the range from -200'000 to +200'000 years. However, by default the planet positions are only properly calculated for dates from -3000 to +3000. You can expand this range by installing a [[solar_system#ephemeris|JPL ephemeris file]].\\
+Beware with the negative years: 1BC is the year 0 and 2BC is the year -1. Note that the entered time is the local time (legal time) of the defined observatory location. \\
 You also can set **[[http://en.wikipedia.org/wiki/Julian_day|JD time]]** by using the input area and the JD calendar dialog box. \\
 === fixed time buttons ===
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 ===== Simulation =====
-{{  en:documentation:simulation.jpg|}}
+{{  en:documentation:simulation.jpg|}}\\
 SkyChart can display the movement of the solar system objects (Sun, planets, moons, asteroids and comets) for a period of time in one single chart. The part of the orbit that those objects move during this time, can be displayed by a line and positions at a choosen interval.\\ You define the total period of time by setting values in the combo boxes **Number of steps**, **every** (which can be read as the **step size** or interval) and selecting a **unit** with the radio button group. If you set //Number of steps// to 10, set //every// to 7 and //unit// to day, you will display the movement of solar objects the next ten weeks from the set date and time. \\ \\
 With the radio buttons you can choose which solar system objects to display, if, and how you want to display labels for these objects.
 {{en:documentation:simul_ex.jpg|}}
 \\
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 You can try this options from a command line window before to put them here. The image sequence from the last animation run is keep until a new animation is run. So you can use them to try new option or even use another software to assemble them. You will find the files in the tmp folder under the [[en:documentation:directories_and_files|User settings]] directory. \\
-The default command is "ffmpeg -r 2  -b 18000k -bt 10000k -i %06d.jpg skychart1.mp4"
+The default command is "ffmpeg -r 10 -i %06d.jpg -b:v 18000k -bt 10000k  skychart1.mp4"
 It is recommended to use the [[http://www.videolan.org/vlc/|VLC]] software to visualize the resulting video without boring with the codec installation.