Pluto Viewer Help

This form enables you to generate a Postscript file showing the appearance of the Pluto system at a specified time. All bodies are rendered with terminators and shadows as appropriate. Selected background stars can also be included.

In the diagram, Pluto 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.

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.

Change History

2.8 (January 28, 2014): Our new tool was released.

Observation Time

The observation time (UTC) can be entered in a variety of formats. For example, the following all parse to 0:01:02 UTC on July 4, 1976: If you want the gory details of how times are interpreted, click here.

Field of View

Enter the field of view of the drawing to be generated and select the appropriate units. Units can be seconds of arc (the default), Pluto radii, Pluto-Charon separation distances (19,571 km), kilometers (projected at the distance to Pluto) or the field of view of the LORRI camera on New Horizons.

Diagram Center

Four different methods of specifying the diagram center are supported. Click on the box to the left of the option you wish to use.

Body: The diagram will be centered on the location of the selected body.

Orbit ansa: The diagram will be centered on the tip of the selected orbital path. Specify the east or west tip 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.

Viewpoint

You may specify the point of view of the diagram. By default, the point of view is the center of the Earth.

Observatory:

Latitude & Longitude: If your desired observatory or location is not on the observatory list, you can enter its latitude, longitude and altitude in the three boxes provided. Latitudes and longitudes can each be specified by up to three values, interpreted as degrees, minutes and seconds. Longitudes can be specified either east or west.

If you wish to have an observatory added to the standard list, or to refine the coordinates of a listed observatory, email the necessary information to Mark Showalter.

Moon Selection

You can decide which moons to include in the diagram. Charon will always be included.

Orbit Selection

You can decide which orbits to include in the diagram. They are shown as dashed lines.

Background Objects

You have several independent options for including background objects in the diagrams. These options make it possible to render diagrams around the times of stellar or spacecraft occultations. Objects are marked by pluses and are labeled by name if the Moon & Star Labels option is activated.

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 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.

Title

Enter a title for the plot in this box. It will appear centered above the diagram.

Moon and Star Labels

Optionally, the diagram will be generated with the name of each moon and star written above and to the right of its center. You may select the size of these labels in points, where a point is 1/72 inches.

Moon Enlargement

The diagram is rendered to scale, which means that some of the smallest Plutonian moons may be very hard to see. You may enter a minimum plotted size for moons in this box. If a nonzero value is used, the smallest moons will be easier to see. The size is in units of points, equal to 1/72 inches. A value of ~4 may be appropriate.

Blank Disks

If you activate this option, all latitude and longitude lines will be suppressed in the diagram. This produces a diagram that is suitable for amateur observers to use as a drawing blank.


Pluto Viewer Form | Rings Node Tools | Rings Node Home

Last updated 28 February 2014.

Mark Showalter