Neptune Moon Tracker Help

This form enables you to generate a Postscript file showing the east-west motion of Neptune's satellites within a specified time period. The distance of each selected moon from the planet's axis is plotted in units of either arcsec or Neptune radii. Positive values correspond to bodies on the "morning" (east) side of Neptune and negative values by the "evening" (west) side. In the diagram, the limbs of Neptune are indicated by a dark gray stripe down the middle. The location of the Adams Ring can be added as a band in lighter gray. Time increases downward on the plot.

The Moon Tracker tool also allows you to download an ASCII table containing the numeric values that went into the diagram. The file contains a single header line followed by the numbers. Columns are as follows:

Change History

1.0 (February 3, 1997): Original Neptune Moon Tracker on line.
2.0 (January 12, 1999): Revised user interface. Extended ephemeris time limits.
2.1 (February 1, 1999): Added new ephemeris option.
2.2 (December 1, 2009): Updated the default ephemerides. To reduce confusion, we have removed the choice about what ephemeris to use.
2.5 (January 23, 2013): Renumbered for consistency across all the Moon Tracker tools. Ephemeris updates.
2.6 beta (January 4, 2016): Ported to new server. Ephemeris updates.
2.7 (October 14, 2020): Ephemeris updates.
2.8 (June 20, 2021): Ephemeris updates.

Time Limits

The start and stop times (UTC) of the plot 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.

Interval: Enter the time interval to be used for the tabulation as a number in the box, and select the time unit from the choices provided. Start times and intervals are rounded to the nearest minute.

Plot Options

Scale: Enter the numeric range and units of the horizontal axis. The value you enter is actually half the width of the diagram; for example, if you enter 10 Neptune radii, then the axis will run from -10 to 10. Zero always falls at the middle of the plot.

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

Moon Selection

Click on the box to the left of each moon that you wish to include in the diagram and in the tabulation.

Ring Selection

Click on the box to include the outer boundary of the ring system (i.e. the Adams Ring) in the plot. It will appear as a vertical gray stripe on each side of the planet.

Neptune Moon Tracker Form | Node Tools | Ring-Moon Systems Node Home

Last updated June 20, 2021.

Mark Showalter