In the diagram, Jupiter and the moons are modeled as triaxial ellipsoids, and are drawn with latitude and longitude contours at 15 degree intervals. Illuminated regions are indicated with black lines; unilluminated regions and terminators are shown as light gray. Penumbral shadows are not indicated.
Optionally, the main and gossamer rings are also drawn. The rings are are shown in black if illuminated and in gray if not or if the opposite side is illuminated. The main ring is shown by its inner and outer boundaries; the gossamer ring is shown by separate Amalthea and Thebe rings, each indicated by a pair of dashed lines at the ring's upper and lower vertical limits.
The diagram is oriented with J2000 declination increasing upward and with right ascension increasing to the left. The frame has uniformly-spaced tick marks along each axis. The declination axis is labeled in degrees, minutes and seconds; the right ascension axis is labeled in hours, minutes and seconds.
Each diagram includes a caption that summarizes the key parameters used to generate it.
Limitations. The outer irregular satellites of Jupiter are not shown.
Body: The diagram will be centered on the location of the selected body.
Ring ansa: The diagram will be centered on the ansa of the selected ring. Specify the east or west ansa using the second box. Note that east is toward the left in the diagram.
J2000 RA and dec: The diagram will be centered on the specified pair of right ascension and declination coordinates. The first box is for the RA and the second box is for the dec. You may also specify whether the RA is in units of hours or degrees. Enter up to three values in each box, separated by spaces; these values are interpreted as degrees/hours, minutes and seconds, respectively. Any or all values can have fractional parts.
Star name: Enter the name of a star as it appears in the current list. The name must match exactly.
Optionally, you can include a rendering of the Io torus by checking the associated box. If selected, the torus is shown as a dashed line. In the adjacent text boxes you can enter the desired inclination and radius; default values correspond to the centrifugal equator at Io's orbit. An inclination of zero corresponds to the equatorial plane and an inclination of 9.6 degrees corresponds to the magnetic equator.
Standard stars: Check the box to include any of a standard list of stars that happen to fall inside the field of view of the diagram. The Jupiter Viewer does not access a star catalog; instead, it only plots stars from a finite list. To view the current star list, click here. This list is updated periodically at the request of the users; if you would like to have a star added to the list, email the necessary information to Mark Showalter.
Additional star: In addition to or instead of the standard stars, you can specify one additional star to be included in the diagram. Check the box to the left and enter the star's RA, dec, and name in the three boxes. You may also specify whether the RA is in units of hours or degrees. Enter up to three values in the RA and dec boxes, separated by spaces; the values are interpreted as hours/degrees, minutes and seconds, respectively. Any or all values can have fractional parts.
Other bodies: Check each box to mark the location of the specified body or spacecraft in the diagram.
Last updated 23 January 2013.