Space-time functions are accessible from "Space-time" menu. (See Using Starlogin)

Planets rise and set hours

Select the planet the hours of which you want to know, on the following dialog box, after having clicked on the "Rises – Sets" button of the corresponding chart.

On the following window, you can see the location of the event on the world map (Shown by a curved cross), and the projected position of the planet. In addition, the equator (hizontal green dotted line), the Greenwich meridian (vertical green dotted line) and the ecliptic are shown. Finallly, you can also see the limit between the nocturnal and the diurnal zones for the planet (orange widely curved line).

The arrow up indicates where the planet is currently rising (for the date and hour of the chart). The other one indicates where it is setting. For the countries between the two arrows, from right to left, the planet is not visible. On the above picture, the Sun is not visible in Africa, for example, but it is about noon for Mexico and part of the US (California, e.g.). During a day, the Earth turns from west to east, so the planets seems to turn from east to west (right to left on the chart) and the limit line and arrows move with the planet.

Apparent angle and distances between two planets

Apparent angle and distance between two planetsare calculated from the "Distances" button of the chart.

In the corresponding window, select the two planets the angle and the distance of which you want to know, before validating.

Distance between two Earth places

The angular and kilometric distances between two earth places are calculated from "Distance between two places" submenu of "Space-time" menu.

In the corresponding window, enter the coordinates (latitude and longitude) for each place the distance between which you want to know, before validating.

Alignments and angles between three Earth places

The alignment and the angles between three earth places are respectively calculated from "Alignment between three places" submenu of "Space-time" menu and from "Angles between three places" one.

In the corresponding window, enter the coordinates (latitude and longitude) for each place, before validating.

Various Time or Space conversions

Several conversions are available from the "Conversions" submenu from the "Space-time" menu:

Greenwich sidereal time at midnight calculation

• The Greenwich Sidereal Time at midnight (0h TU) is calculated from "Greenwich time" option.
• In the corresponding window, enter the date for which you want to know the Greenwich Sidereal Time at midnight, before validating.

Find the week day name of a date

• The week day name of a given date is calculated from "Week day" option.
• In the corresponding window, enter the date the weekday name of which you want to know, before validating.

Find Easter date

• The (Catholic) Easter date for a given year is calculated from "Easter date" option.
• In the corresponding window, enter the year the Easter date of which you want to know, before validating.

Julian days and Gregorian dates

• The conversion between a Gregorian calendar date and the corresponding Julian day is done from "Julian days" option.
• In the corresponding window,
  • either enter the Julian day before pressing the "Enter" or "Carriage return" key to calculate the equivalent Gregorian date,
  • or enter the Gregorian day before pressing the "Enter" or "Carriage return" key to calculate the equivalent Julian day.

Universal and local sidereal times

• The conversion between a universal time hour and the equivalent local sidereal time hour is done from "Time" option.
• In the corresponding window, enter the considered date and the earth location, then:
  • either enter the UT hour before pressing the "Enter" or "Carriage return" key to calculate the equivalent local sidereal time hour,
  • or enter the local sidereal time hour before pressing the "Enter" or "Carriage return" key to calculate the equivalent UT hour.

Astronomical and geographical latitudes

• The conversion between the astronomical latitude of a considered earth location and the geographical one is done from "Latitudes" option.
• In the corresponding window, enter the altitude of the earth location, then:
  • either enter the astronomical latitude before pressing the "Enter" or "Carriage return" key to calculate the equivalent geographical one,
  • or enter the geographical latitude before pressing the "Enter" or "Carriage return" key to calculate the equivalent astronomical one.

Decimal and sexagesimal degrees

• The conversion between a number of degrees in decimal form and the same in sexagesimal form is done from "degrees" option.
• In the corresponding window,
  • either enter the number of decimal degrees before pressing the "Enter" or "Carriage return" key to calculate the equivalent number of sexagesimal degrees,
  • or enter the number of sexagesimal degrees before pressing the "Enter" or "Carriage return" key to calculate the equivalent number of decimal degrees.

Distance units

The conversion between a number of degrees in decimal form and the same in sexagesimal form is done from "degrees" option.

In the corresponding window, write a number in the text box for the initial unit. As you are writing, the conversion into the other units are automatically displayed.

Different calendars

The conversion between about twenty different calendars is done from "Calendars" submenu of "Space-time" menu.

In the corresponding window, select the initial calendar and enter the date expressed with this one. Separate the month, the day and the year using a "/". The date in each other calendar is then automatically calculated and shown as soon as you begin to write the year.

For the maya long cycle calendar, you must enter five different numbers, separated with a "/". The date in the "Tzolkin & Haab" maya calendar will then be given with the one for the other calendars, as soon as the fifth number is written. But you can't write anything in the text box for the "Tzolkin & Haab", since many dates, in other calendars, correspond to a given Tzolkin & Haab one.