DATA_SET_DESCRIPTION |
Required Reading
================
The format of all Alice data are described in detail by the EAICD
document located in the /DOCUMENT directory. In addition, the
Rosetta Alice logbook file, RA_LOGBOOK_NNN.ASC, also located in
the DOCUMENT directory provides observational details such as
observation target, commanded exposure time, etc., for all Alice
data. The Alice team strongly recommends reading this
documentation before using the data.
Data Set Overview
=================
This data set contains calibrated, data acquired by the Rosetta
Orbiter ALICE UV Spectrometer during the Cruise 4A mission phase.
All data were obtained as part of the Active Checkout PC8 which
occurred during this mission phase. A detailed listing of all
Alice observations is given in the observation log file located in
the DOCUMENT directory.
The following operations took place during the period covered by
this data set:
# Payload Checkout #8 (PC8)
# 2008 July 5-27
# Alice activity overview:
# * 2008 Jul 05 01:15 - AL01 (passive checkout; 2 hr)
# * 2008 Jul 05 03:20 - AL02 (decontamination; 25 hr, 22hr heater +
3hr cooldown)
# * 2008 Jul 06 04:30 - AL09A (Service 19 test with GIADA; 1.5 hr)
# * 2008 Jul 11 16:55 - AL05 (Blank Sky field #2; 24 hr)
# * 2008 Jul 12 18:10 - AL06A, AL03A, AL08A (Vega cal; 3 hr)
# * 2008 Jul 12 22:20 - AL06B, AL03B, AL08B (alp Gru cal; 3 hr)
# * 2008 Jul 13 03:00 - AL06E, AL03E, AL08E (HD 93521 cal; 12 hr)
# * 2008 Jul 13 19:35 - AL07 (dark calibration; 3 hr)
# * 2008 Jul 19 15:30 - AL_ICE, AL_ICS (interference campaign;
infrequently over a period of ~8.5 hr)
# * 2008 Jul 20 22:30 - AL99A (flight software patch, v2.06; ~50 min)
# * 2008 Jul 26 10:05 - AL99B (validation test of flight software
patch, v2.06; 2 hr)
# * 2008 Jul 26 14:05 - AL09A (Service 19 test with ROSINA; 1.5 hr)
# * 2008 Jul 26 15:40 - AL02 (decontamination; 25 hr, 22hr heater +
3hr cooldown)
Processing
==========
The data in this data set are calibrated, CODMAC Level 4 data. As
such, corrections for detector dead time, dark counts, flatfield,
and effective area have generally been applied. The primary FITS
header contains a list of which corrections have been applied to
that file.
The CODMAC level 4 data product (LIN) differs from the CODMAC
level 3 data product (SCI) in that the units of the data are
photons s^-1 cm^-1 Angstrom^-1 (as opposed to photons s^-1 cm^-1)
and the data have been resampled such that the wavelength scale is
linear and common to all level 4 data.
Data
====
The data are in FITS format and text format. Each FITS file has a
detached PDS label so that they can be read either by FITS or PDS
tools. A detailed description of the data format is given in the
ALICE EAICD document located in the DOCUMENT directory of this
data set.
Ancillary Data
==============
No ancillary data included in this data set.
Coordinate System
=================
The geometry items SC_SUN_POSITION_VECTOR,
SC_TARGET_POSITION_VECTOR and SC_TARGET_VELOCITY_VECTOR provided in
the label of the data product are relative to the Earth Mean
Equator frame of J2000.
SUB_SPACECRAFT_LATITUDE, SUB_SPACECRAFT_LONGITUDE are given in the
PLANETOGRAPHIC coordinate system. These parameters are computed at
time t=START_TIME. Distances are given in km, angles in degrees.
Software
========
All FITS readers should be able to successfully read the data.
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