Four by Jove displays the precise location of the four main moons of Jupiter. Four By Jove will show the transits and shadow transits of the Galilean moons across Jupiter's disk and the occultations and eclipses of the four main moons, Io, Europa, Ganymede, and Callisto by Jupiter. These are the Jupiter events. Four By Jove will also show mutual events such as umbral eclipses and occultations of one satellite by another.
Four By Jove makes use of the advanced E2 theory by Lieske. Near term accuracy is on the order of +/- eight kilometers.
Twenty four predictions of Jupiter events can be made. Transits, shadow transits, occultations, and eclipses of the Galilean satellites will be given for the time of the mid event.
XYZ coordinates of the Galilean moons is given to within one ten thousandth of the radii of Jupiter.
Twenty four hour predictions of mutual events can be made. If one satellite umbral eclipses another or occults another the information will be presented. You will be told if the event is visible, the time the event starts and ends and the time of mid event. You will be given an approximate percentage of light reduction. In the case of umbral eclipses the size of the umbral shadow is given as well as its XY position in reference to the eclipsed satellites center. In the case of an occultation the XY position of the occulting satellites center from the occulted satellites center is given. Since these mutual events occur every six years you can determine if such a series of events is likely at the given time.
Jovian satellite activity can be displayed. Four portals stay fixed on each of the Galilean satellites, two other portals allow views of transits and shadow transits across Jupiter's disk. Another portal gives a binocular like view of the moons.
A simple slider control allows gross or fine control of the time over a twenty four hour period. Indeed; you can move the control minute by minute forward or backward to see the details of an event. You will see umbral shadows of the proper size and position sweep over another satellite if it happens.
No surface details of the satellites are shown nor are the cloud belts of Jupiter displayed.
The altitude and azimuth of Jupiter is given for your location and time.
Data can be saved or printed in a text format.
Images are not saved but other software such as Paint Shop can capture screen shots.
Near term accuracy for the present should be extremely precise. Longer term accuracy back to 4000 BC or toward 10,000 AD will have less precision.
Screen shot of Europa eclipses Io; April 7, 1980. This event was unpredicted at the time,
The eclipse of Io by Europa is underway. Europa's shadow is coming in from the right in Io's portal. Notice how the shadow transits of Io and Europa are beginning to merge in portals that show Jupiter's disk. Time 19:57 UT.
Near mid-eclipse; 20:09 UT. Io's light reduced by 55%. The shadow transits on Jupiter's disk have merged.
The eclipse is drawing to a close; 20:21 UT. Notice how the shadow transits are separating as well.
Four by Jove showing some of the information for the mutual event displayed above.
Screen shot of November 23, 1988 showing Ganymede in inferior conjunction and so is its nearby shadow.