Links To:   Data  |  Browse Files  |  Documents  |  File Formats  |  File Naming (Data, Browse)


 

Magnetometer Data

in the Lunar Prospector MAG/ER Level 1B Archive

 

Overview

The Magnetometer (MAG) vector data reside in the directory DATA/MAG. The data files are in subdirectories containing data from single months; the names of these subdirectories indicate the year and month (with month number and name) of the data. On this disk, the monthly subdirectories are 99_04APR, 99_05MAY, 99_06JUN, and 99_07JUL.

The file naming convention for files in the one-month subdirectories of the DATA/MAG directory is illustrated by the following example. (The file mentioned here is only an example; there are many more such files on the disk.)

MA990401.TAB is interpreted as

MA = 'MAG data'
99 = year 1999
04 = month 04 (April)
01 = day 01 in month
TAB = 'table' format

MA990401.LBL is the name of the PDS label file which describes the data file MA990401.TAB. Such label files provide descriptive information about the data files in a format which is both human-readable and machine-readable.

This disk also contains browse plots which summarize some of the MAG data and other data.

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Documents

This disk contains documentation files which describe the datasets on the disk, the instruments from which the data came, and the Lunar Prospector spacecraft and mission. These files are found in the CATALOG and DOCUMENT directories.

Of particular interest to users of MAG data are the following files.

In the CATALOG directory:

In the DOCUMENT directory:

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File Formats

The files on this disk are in level 1 compliance with the ISO 9660 standard. The disk contains data for 5 calendar months. The MAG data are provided as ASCII tables of 1 day duration in Selenocentric Solar Ecliptic (SSE) and Selenographic (SEL) coordinates. The naming convention for these files is described earlier in this document.

The format of the data in the MAG files is described in the PDS labels (*.LBL files) accompanying the MAG data files. These label files are both human-readable and machine-readable.

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Browse Files

In addition to the data files, this disk contains graphical browse plots, in GIF87A format, summarizing the Magnetometer (MAG) and Electron Reflectometer (ER) data on the disk. These plots are contained in the BROWSE directory.

Each browse file contains plots of the following items for a 12-hour period: electron count rate (at various energies); electron energy spectrum; magnetic field, as magnitude |B| and direction (phi, theta); polarity; and Sun sensor data. The data are plotted against two time scales (decimal day-of-year and hour-minute) and a scale of GSE longitude.

The naming convention for browse plots is illustrated by the following example. (The file mentioned here is only an example; there are many such files on the disk.)

9909112.GIF is interpreted as

99 = year 1999
091 = day of year 091 (where Jan. 1 = day of year 001)
12 = start time 1200 (in 24-hour time; 00 minutes is implied)
GIF = file in GIF format.

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Links to Data and Browse Files

The following links can be used to navigate the MAG data files and browse files on this disk.

General information about the data: The data are provided as ASCII ''tables'' of 1 day duration in Selenocentric Solar Ecliptic (SSE) and Selenographic (SEL) coordinates. The SSE coordinate system has its X-axis along the Moon-Sun line, positive towards the Sun. The Z-axis is parallel to the northward normal to the Earth's ecliptic plane, and Y completes the right-handed set. The SEL coordinate system used here is a Cartesian representation that places the Z-axis along the rotation axis of the Moon, positive in the direction of angular momentum. The X-axis lies in the lunar equatorial plane at 0 degrees longitude, and Y completes the right-handed set.

Links to data for: April 1999 | May 1999 | June 1999 | July 1999

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