DATA_SET_DESCRIPTION |
Data Set Overview
=================
The eight color asteroid survey provides reflectance spectra for
minor planets using eight filter passbands. This dataset includes
the primary data obtained for 589 minor planets, the mean values
for each minor planet included in the survey, the principal
component scores derived from the primary data, the response
curves, effective wavelengths, and bandpasses for the filters, and
the coordinates and values determined for standard stars defining
the system. With version 3.0, five additional files were added
to provide, overall class color indices and albedos, eigenvalues,
the color index correlation matrix and the component loading matrix.
Data
====
The compiled data are provided in ten ASCII data tables:
ecas.tab - Primary data
ecasmean.tab - Mean values derived from primary data
ecaspc.tab - Principal component scores for each asteroid,
derived from the primary data
ecasev.tab - Eigenvectors used in computing the principal
component scores (version 3.0 and later)
ecascm.tab - The color index correlation matrix (version
3.0 and later)
ecasclm.tab - The component loadings matrix (version 3.0 and
later)
colorind.tab - Average and extreme color indices for each
asteroid class (version 3.0 and later)
classalb.tab - Average and extreme albedo values for each
asteroid class (version 3.0 and later)
ecasstds.tab - Standard stars defining the ECAS photometric
system
ecasband.tab - Effective wavelengths and bandpasses of the
filters
ecasfltr.tab - Transmission curves for the eight filters
used, and transmission and reflectance curves
of the dichroic beam-splitter
In addition, the mean spectra of the 'ecasmean.tab' file are also
provided as individual spectrum files, one for each object.
Modification History
====================
Five new data files were added for version 3.0:
1. classalb.tab
2. colorind.tab
3. ecasclm.tab
4. ecascm.tab
5. ecasev.tab
In addition, each existing data file and label was examined for
compliance with current PDS standards and SBN practices. The
following changes were made to existing data files:
o In the ecas.tab, ecasmean.tab and ecaspc.tab files, names
were added for those asteroids having official names.
o In the ecas.tab file, the time of observation field has
been reformatted from a 'YYMMDD.ddd' format to the
standard 'yyyy-mm-ddThh:mm' format.
o In PDS labels, the non-standard unit 'MILLIMAGNITUDE' was
replaced by 'MAGNITUDE' with a SCALING_FACTOR value of
'1.E-03'.
In addition, the mean spectra in the ecasmean.tab file were split
into separate files to facilitate plotting. The spectrum for
152 Atala is omitted from this collection because of the notation
in the main data file casting doubt on the quality of the data.
Media/Format
============
This dataset is released in the form of ASCII files which may be
stored on disk or other magnetic medium and which may be
distributed by ftp, email, real-time access by remote login, or by
whatever means is most convenient.
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