The MESSENGER mission dictionary contains classes that describe aspects
of the MESSENGER mission and related instruments.
1.0.0.0 (2018-05-02)
Updated PDS4 model to 1.9.0.0, may want to further update to 1.A.0.0.
Corrections and additions by E. Guinness, Geo Node, as noted in comments
below. Also changed all DD_Assocation clasess to have identifier_reference instead of
local_identifier so that the ingest file works with 1.9.0.0
1.0.1.0 (2018-06-22)
S. Slavney: Added orbit_number element. Removed erroneous leading space from mission
phase name value "Mercury 4 Cruise".
Build with lddtool -lpMs
1.0.2.0 (2018-10-29)
T. King: Add ec_factor and make img_id_lsb, img_id_msb, piv_pos_motor and piv_goal nillable as requested by Paul Geissler.
Also made mission_phase_name multiple occurrence.
1.1.0.0 (2019-06-07)
T. King: Add observation_id, observation_type, data_quality_id, smear_magnitude, dark_strip_mean, missing_pixel_count, saturated_pixel_count and ec_factor as requested by Paul Geissler.
The MESSENGER MDIS class is the container for
MESSENGER MDIS specific metadata elements.
The MESSENGER class is the container for
MESSENGER mission-specific metadata elements.
This section contains the simpleTypes that provide more constraints
than those at the base data type level. The simpleTypes defined here build on the base data
types. This is another component of the common dictionary and therefore falls within the
common namespace.
The background brightness used for MDIS
automatic exposure time calculation. In a test image that it
analyzed to determine an exposure time using automatic exposure,
DPU hardware generates a histogram of the image. The histogram
is analyzed by the software to determine if the image is
overexposed or underexposed, and the exposure time is adjusted
accordingly by analyzing the histogram of raw DN values in
different brightness bins. The background or dark current level
(mess.mdis.aex_bacb) is taken into account an is assumed to be a
constant value. A threshold of number of pixels
(mess.mdis.aex_sthr) is allowed to exceed a target brightness
(mess.mdis.aex_tgtb). Starting with the maximum value, the
number of pixels exceeding the target is counted, and the
brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The maximum allowable exposure time from an MDIS
automatic exposure time calculation. In a test image that it
analyzed to determine an exposure time using automatic exposure,
DPU hardware generates a histogram of the image. The histogram
is analyzed by the software to determine if the image is
overexposed or underexposed, and the exposure time is adjusted
accordingly by analyzing the histogram of raw DN values in
different brightness bins. The background or dark current level
(mess.mdis.aex_bacb) is taken into account an is assumed to be a
constant value. A threshold of number of pixels
(mess.mdis.aex_sthr) is allowed to exceed a target brightness
(mess.mdis.aex_tgtb). Starting with the maximum value, the
number of pixels exceeding the target is counted, and the
brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The minimum allowable exposure time from an MDIS
automatic exposure time calculation. In a test image that it
analyzed to determine an exposure time using automatic exposure,
DPU hardware generates a histogram of the image. The histogram
is analyzed by the software to determine if the image is
overexposed or underexposed, and the exposure time is adjusted
accordingly by analyzing the histogram of raw DN values in
different brightness bins. The background or dark current level
(mess.mdis.aex_bacb) is taken into account an is assumed to be a
constant value. A threshold of number of pixels
(mess.mdis.aex_sthr) is allowed to exceed a target brightness
(mess.mdis.aex_tgtb). Starting with the maximum value, the
number of pixels exceeding the target is counted, and the
brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The bin in a DPU histogram of image brightness
used for MDIS automatic exposure time calculation. In a test
image that it analyzed to determine an exposure time using
automatic exposure, DPU hardware generates a histogram of the
image. The histogram is analyzed by the software to determine if
the image is overexposed or underexposed, and the exposure time
is adjusted accordingly by analyzing the histogram of raw DN
values in different brightness bins. The background or dark
current level (mess.mdis.aex_bacb) is taken into account an is
assumed to be a constant value. A threshold of number of pixels
(mess.mdis.aex_sthr) is allowed to exceed a target brightness
(mess.mdis.aex_tgtb). Starting with the maximum value, the
number of pixels exceeding the target is counted, and the
brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The number of pixels allowed to exceed target
brightness during an MDIS automatic exposure time calculation.
In a test image that it analyzed to determine an exposure time
using automatic exposure, DPU hardware generates a histogram of
the image. The histogram is analyzed by the software to
determine if the image is overexposed or underexposed, and the
exposure time is adjusted accordingly by analyzing the histogram
of raw DN values in different brightness bins. The background or
dark current level (mess.mdis.aex_bacb) is taken into account an
is assumed to be a constant value. A threshold of number of
pixels (mess.mdis.aex_sthr) is allowed to exceed a target
brightness (mess.mdis.aex_tgtb). Starting with the maximum
value, the number of pixels exceeding the target is counted, and
the brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The target brightness used for MDIS automatic
exposure time calculation. In a test image that it analyzed to
determine an exposure time using automatic exposure, DPU
hardware generates a histogram of the image. The histogram is
analyzed by the software to determine if the image is
overexposed or underexposed, and the exposure time is adjusted
accordingly by analyzing the histogram of raw DN values in
different brightness bins. The background or dark current level
(mess.mdis.aex_bacb) is taken into account an is assumed to be a
constant value. A threshold of number of pixels
(mess.mdis.aex_sthr) is allowed to exceed a target brightness
(mess.mdis.aex_tgtb). Starting with the maximum value, the
number of pixels exceeding the target is counted, and the
brightness of the histogram bin in which that threshold is
reached (mess.mdis.aex_stat) is reported. The exposure time is
scaled back by the ratio of
mess.mdis.aex_tgtb/mess.mdis.aex_stat.
The mission-elapsed-time, or MET, in seconds
since MESSENGER launch, of the second during which the
spacecraft attitude measurement in the header of an MDIS image
was acquired.
Attitude quality flag for the spacecraft
attitude quaternion in the header of an MDIS image: 7 = Attitude
Knowledge OK (At least 1 Star Tracker is available and at least
50% of gyro data is valid) 6 = Attitude Knowledge OK (No Star
Tracker is available but at least 50% of gyro data is valid) 5 =
Attitude Knowledge OK (No Star Tracker is and between 10% and
50% of gyro data is valid -OR- At least 1 Star Tracker is valid
and between 0% and 50% of gyro data valid) 4 = not a legal
option 3 = Attitude Knowledge BAD (At least 1 Star Tracker is
available and at least 50% of gyro data is valid) 2 = Attitude
Knowledge BAD (No Star Tracker is available but at least 50% of
gyro data is valid) 1 = Attitude Knowledge BAD (No Star Tracker
is available and between 10% and 50% of gyro data is valid -OR-
At least 1 Star Tracker is valid and between 0% and 50% of gryo
data is valid) 0 = Attitude Knowledge BAD (No Star Tracker data
fewer than 10% of gyro data valid).
The roll value of the vector component of the
attitude quaternion representing spacecraft attitude, in the
header of an MDIS image.
The pitch value of the vector component of the
attitude quaternion representing spacecraft attitude, in the
header of an MDIS image.
The yaw value of the vector component of the
attitude quaternion representing spacecraft attitude, in the
header of an MDIS image.
The scalar component of the attitude quaternion
representing spacecraft attitude, in the header of an MDIS
image.
The temperature of the focal plane array in raw
counts at observation time. The conversion formula to degrees
Celsius depends on the camera performing the observation: For
WAC: Temperature = -263.2584 + Raw * 0.5022 For NAC: Temperature
= -268.8441 + Raw * 0.5130 Where Raw is the raw counts in
telemetry (mess.mdis.cam_t1).
Camera temperature 2 in raw counts. The meaning
depends on whether it is being reported by the WAC or NAC. A
single telemetry point is used to return the raw value of filter
wheel temperature (WAC), FILTER_TEMPERATURE once converted to
units of degrees Celsius, or the raw value of telescope
temperature (NAC), OPTICS_TEMPERATURE once converted to units of
degrees Celsius, depending on which camera is in use. For the
WAC, this is temperature of the filter wheel. Thus,
FILTER_TEMPERATURE is 'N/A' if the NAC was used for the
observation because the telemetry point will be a measurement of
the NAC telescope temperature. For the WAC the conversion from
raw counts to degrees Celsius is: T = -292.7603 + Raw * 0.5553
where Raw is the raw counts in MESS:CAM_T2. For the NAC, this is
temperature of the NAC telescope. Thus OPTICS_TEMPERATURE is
'N/A' if the WAC was used for observation because the telemetry
point will be a measurement of the WAC filter wheel temperature.
For the NAC the conversion from raw counts to degrees Celsius
is: T = -269.7180 + Raw * 0.4861 where Raw is the raw counts in
telemetry (mess.mdis.cam_t2).
MDIS CCD temperature in raw counts. The
conversion formula to degrees Celsius depends on the camera
performing the observation: For WAC: Temperature = -318.4553 +
Raw * 0.2718 For NAC: Temperature = -323.3669 + Raw * 0.2737
Where Raw is the raw counts in telemetry
(mess.mdis.ccd_temp).
12 to 8 bit image compression enabled or
disabled. Which algorithm is used is specified by
MESS.
12 to 8 bit compression algorithm (0-7) used to
compress images from 12 to 8 bits. Whether this option is
enabled is indicated by mess.mdis.comp12_8. The compression is
implemented using one of eight lookup tables, which are
optimized to the lower WAC CCD read noise and higher NAC read
noise, light levels, and bias level (nominal or after inflight
drift).
Status of lossless Fast compression of MDIS
images. This is applied to images by the instrument itself. The
images are first uncompressed on the solid-state recorder if
lossy wavelet compression is applied.
When true, this indicates that the MDIS image is
a critical optical navigation image and will be compressed by
the MESSENGER Main Processor (MP) before other images. Normally,
the MP compresses images in the order that they are
received.
The dark_strip_mean element provides the mean
value of the pixels in the dark strip area of a CCD. The dark
strip is an area of the CCD which is covered in such a way as to
receive no light. The dark strip provides a measure of the dark
current in the CCD.
The data_quality_id element provides a numeric
key which identifies the quality of data available for a
particular time period. The data_quality_id scheme is unique to
a given instrument and is described by the associated
data_quality_desc element.
The value indicates what detector of the GRS
instrument measured the observation.
Priority for downlink of an MDIS image file from
the MESSENGER spacecraft.
The identified of the DPU used during
acquisition of an MDIS image.
The ec_factor element records the empirical
correction factor used to process MDIS WAC CDRs.
Exposure time mode used for acquisition of an
MDIS image. Manual exposure uses a pre-commanded exposure time.
Autoexposure determines the exposure time from test images taken
before the exposure, targeting a specific brightness
value.
MDIS exposure time in
milliseconds.
On-chip image binning option for MDIS. Images
may be taken either without on-chip binning or with 2x2 binning,
which decreases the size of a full image from 1024x1024 pixels
to 512x512 pixels. On-chip binning can be used to manage the
size of raw images being stored on the spacecraft solid-state
recorder, or to increase CCD sensitivity. If this option is
used, sensitivity increases by about a factor of four but read
noise is similar.
The goal position, in raw counts of the position
resolver on the MDIS filter wheel. For each commanded filter
number, the instrument software will try to place the filter
wheel at the following positions: FILTER_NUMBER
mess.mdis.fw_goal 1 17376 2 11976 3 6492 4 1108 5 61104 6 55684
7 50148 8 44760 9 39256 10 33796 11 28252 12 22852 Actual
position attained is reported in
mess.mdis.fw_pos.
The actual position, in raw counts of the
position resolver on the MDIS filter wheel. For each commanded
filter number, the instrument software will try to place the
filter wheel at the following positions: FILTER_NUMBER
mess.mdis.fw_goal 1 17376 2 11976 3 6492 4 1108 5 61104 6 55684
7 50148 8 44760 9 39256 10 33796 11 28252 12 22852 Commanded
position is reported in mess.mdis.fw_goal. There is a tolerance
of 240 resolver counts around mess.mdis.fw_goal for
mess.mdis.fw_pos to indicate that the filter wheel is correctly
positioned.
Validity flag for position of the MDIS filter
wheel given in mess.mdis.fw_pos.
The raw value from the MDIS filter wheel
resolver in resolver counts. It is used by the flight software
to compute mess.mdis.fw_pos. For each commanded filter number,
the instrument software will try to place the filter wheel at
the following positions: FILTER_NUMBER mess.mdis.fw_goal 1 17376
2 11976 3 6492 4 1108 5 61104 6 55684 7 50148 8 44760 9 39256 10
33796 11 28252 12 22852 Commanded position is reported in
mess.mdis.fw_goal. There is a tolerance of 240 resolver counts
around mess.mdis.fw_goal for mess.mdis.fw_pos to indicate that
the filter wheel is correctly positioned.
Validity flag for reading of the MDIS filter
wheel given in mess.mdis.fw_read.
Which of the two cameras was used during
acquisition of an MDIS image.
The 16 least-significant-bits of the 24-bit
unique image identifier from the raw image header. This item was
added to images effective with an instrument software update
2009-08-18 and will be set to N/A in images aquired
earlier.
The 8 most-significant-bits of the 24-bit unique
image identifier from the raw image header. This item was added
to images effective with an instrument software update
2009-08-18 and will be set to N/A in images aquired
earlier.
When true, this indicates that an MDIS image is
subsampled by jailbars, a subset of all the image columns that
are downlinked to save data volume in optical navigation images.
The start column, stop column, and column spacing are indicated
by mess:jb_x0, mess:jb_x1, and mess:jb_space respectively.
Jailbars are defined in the original 1024x1024 pixel MDIS
coordinate system before pixel binning as described by
mess_fpu_bin and mess:pixelbin.
The column spacing for jailbars in an MDIS
image, a subset of all the image columns that are downlinked to
save data volume in optical navigation images. Jailbars are
defined in the original 1024x1024 pixel MDIS coordinate system
before pixel binning as described by mess_fpu_bin and
mess:pixelbin.
The start column for jailbars in an MDIS image,
a subset of all the image columns that are downlinked to save
data volume in optical navigation images. Jailbars are defined
in the original 1024x1024 pixel MDIS coordinate system before
pixel binning as described by mess_fpu_bin and
mess:pixelbin.
The stop column for jailbars in an MDIS image, a
subset of all the image columns that are downlinked to save data
volume in optical navigation images. Jailbars are defined in the
original 1024x1024 pixel MDIS coordinate system before pixel
binning as described by mess_fpu_bin and
mess:pixelbin.
Indicator if MDIS FPU is latched up. If the
value is 1 then the image data are probably
invalid.
The mission-elapsed-time, or MET, in seconds
since MESSENGER launch of the second during which an MDIS image
completes its exposure.
The missing_pixel_count element provides the
number of pixels missing from an image or observation.
The mission_phase_name attribute provides the
mission-defined name of a mission phase.
The observation_id element uniquely identifies a
scientific observation within a data set.
The observation_type element identifies the
general type of an observation.
The orbit_number attribute identifies the number
of the orbital revolution of a spacecraft around a target body.
For MESSENGER, the orbit number was incremented at apoapsis. For
observations made before the spacecraft was in orbit,
orbit_number has no value, and its nilReason attribute is
"inapplicable".
The offset in measured pivot position applied to
mess.mdis.piv_pos and mess.mdis.piv_goal so that zero is as
close as possible to true spacecraft nadir (+z axis). The
correction is in increments of (180 DEGREES /
(2**15)).
The commanded position of the MDIS pivot during
exposure of an MDIS image, in increments of (180 DEGREES /
(2**15)) with zero at nadir. -180 degrees is stowed. This item
is not available after an instrument sofware upload 2009-08-18
and will be set to N/A in images acquired
later.
Status of main processor (MP) control of the
MDIS pivot. If this is enabled, then the pivot goes to a
position broadcast by the MP that points MDIS to nadir or some
other aimpoint. If not enabled then a discrete pivot position is
commanded.
The actual position of the MDIS pivot during
exposure of an MDIS image, in increments of (180 DEGREES /
(2**15)) with zero at nadir. -180 degrees is
stowed.
The actual position of the MDIS pivot during
exposure of an MDIS image, in motor step units. This item is not
available prior to an instrument software upload 2009-08-18 and
will be set to N/A in images taken earlier.
Validity flag for position of the MDIS pivot
given in mess.mdis.piv_pos.
Raw pivot reading from resolver (in units of
resolver counts). The pivot platform resolver only covers 45
degrees of motion; the resolver read-out values repeat eight
times over the entire 360 degrees that an unconstrained platform
could travel. This value is used along with dead-reckoning
knowledge of which octant the platform is in to give the value
in mess.mdis.piv_pos.
Validity flag for reading of the MDIS pivot
given in mess.mdis.piv_read.
Pivot control state of MDIS. A resolver provides
a position reading of the pivot platform. The resolver only
covers 45 degrees of motion; the resolver read-out values repeat
eight times over the entire 360 degrees that an unconstrained
platform could travel. The DPU software must determine in which
of the eight octants the platform is located before the resolver
reading is meaningful. The software combines the octant with the
resolver reading to form a position that covers the entire 360
degrees. To determine the octant the DPU software must be
commanded to 'home' the platform. To home the pivot platform,
the software drives the motor open loop backwards into the hard
stop at -185 degrees. Then the software drives the motor
forward, open loop, prepositioning it to -179 degrees. Until
homing is completed, the pivot platform is considered 'lost' and
all other pivot commands will remain pending. This status item
describes that state of the pivot in determining this position
knowledge.
Pixel binning done to MDIS images by the
MESSENGER spacecraft main processor (MP). This is in addition to
on-chip binning as described by mess_fpu_bin.
The saturated_pixel_count element provides a
count of the number of pixels in the array that are at or exceed
the maximum DN value.
The smear_azimuth element indicates the
direction in which an image was smeared. The values of this
angle increment in a clockwise direction from a horizontal
reference line.
The smear_magnitude element indicates how far an
image was smeared during an exposure.
The name of the software used to generate the
product.
The version of the software used to generate the
product. It usually has the form m.n
Source of an MDIS image, either a scene image
from the CCD or one of two test patterns.
The spacecraft_clock_start_count attribute
provides the value of the spacecraft clock at the beginning of a
time period of interest. A planned reset of the on-board clock
of the MESSENGER spacecraft occurred on January 8, 2013. This
was commanded by Mission Operations and was done because the
integer seconds part of the on-board mission- elapsed-time (MET)
counter is not long enough to contain the larger MET values that
would occur due to the extended mission. The MESSENGER team
elected to command the clock reset and set MET to a small
non-zero value to prevent disruptions in on-board timekeeping
and other effects (that might have occurred if the clock were
allowed to automatically rollover to 0 in early 2013) and to
ensure that the MET counter would accomodate the remaining
extended mission. As a result of the spacecraft clock reset, a
discontinuity was introduced and MET values are no longer
guaranteed to be unique throughout the mission. This ambiguity
is resolved in ground processing by the use of SPICE 'clock
partitions' (partition 1 for pre-reset METs and partition 2 for
post-reset METs) in the Spacecraft Clock (SCLK) kernel (which
supports mapping MET to other time forms using SPICE routines as
described below) and with MET values stored in PDS products,
labels, and for some instruments, product file names. For MET
values in products or labels, a '1/' or '2/' preceding MET
indicates the partition, as in: SPACECRAFT_CLOCK_START_COUNT =
'1/265485874' SPACECRAFT_CLOCK_STOP_COUNT = '2/000100005' When
using SPICE routines, clock partition numbers should be included
with MET input values. METs expressed without an explicit
partition number are associated with clock partition 1 by
default. Use of clock partition numbers in file names for some
MDIS products is described in the MDIS EDR and CDR/RDR SIS
documents with those data sets.
The spacecraft_clock_stop_count attribute
provides the value of the spacecraft clock at the beginning of a
time period of interest. A planned reset of the on-board clock
of the MESSENGER spacecraft occurred on January 8, 2013. This
was commanded by Mission Operations and was done because the
integer seconds part of the on-board mission- elapsed-time (MET)
counter is not long enough to contain the larger MET values that
would occur due to the extended mission. The MESSENGER team
elected to command the clock reset and set MET to a small
non-zero value to prevent disruptions in on-board timekeeping
and other effects (that might have occurred if the clock were
allowed to automatically rollover to 0 in early 2013) and to
ensure that the MET counter would accomodate the remaining
extended mission. As a result of the spacecraft clock reset, a
discontinuity was introduced and MET values are no longer
guaranteed to be unique throughout the mission. This ambiguity
is resolved in ground processing by the use of SPICE 'clock
partitions' (partition 1 for pre-reset METs and partition 2 for
post-reset METs) in the Spacecraft Clock (SCLK) kernel (which
supports mapping MET to other time forms using SPICE routines as
described below) and with MET values stored in PDS products,
labels, and for some instruments, product file names. For MET
values in products or labels, a '1/' or '2/' preceding MET
indicates the partition, as in: SPACECRAFT_CLOCK_START_COUNT =
'1/265485874' SPACECRAFT_CLOCK_STOP_COUNT = '2/000100005' When
using SPICE routines, clock partition numbers should be included
with MET input values. METs expressed without an explicit
partition number are associated with clock partition 1 by
default. Use of clock partition numbers in file names for some
MDIS products is described in the MDIS EDR and CDR/RDR SIS
documents with those data sets.
The standard_data_product_id keyword is used to
identify data products of the same processing level that are not
otherwise indentified by being in different collections within
the bundle.
The number of columns in the FIRST rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of columns in the SECOND rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of columns in the THIRD rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of columns in the FOURTH rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of columns in the FIFTH rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of rows in the FIRST rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of rows in the SECOND rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of rows in the THIRD rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of rows in the FOURTH rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The number of rows in the FIFTH rectangular
subframe within an MDIS image to be retained after image
compression by the MESSENGER spacecraft main processor (MP).
There may be up to five subframes per image as defined by
mess_subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess:fpu_bin and mess:pixelbin.
The zero-based starting column of the FIRST
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting column of the SECOND
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting column of the THIRD
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting column of the FOURTH
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting column of the FIFTH
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting row of the FIRST
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting row of the SECOND
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting row of the THIRD
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting row of the FOURTH
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
The zero-based starting row of the FIFTH
rectangular subframe within an MDIS image to be retained after
image compression by the MESSENGER spacecraft main processor
(MP). There may be up to five subframes per image as defined by
mess:subframe. Subframes are defined in the original 1024x1024
pixel MDIS coordinate system before pixel binning as described
by mess_fpu_bin and mess:pixelbin.
Number of rectangular subframes within an MDIS
image to be retained after image compression by the MESSENGER
spacecraft main processor (MP). Subframes may overlap each
other, and are defined in the original 1024x1024 pixel MDIS
coordinate system before pixel binning as described by
mess:fpu_bin and mess:pixelbin. Either a full image may be
specified, or up to five discrete regions within the full image.
In all cases, the first four columns of the original 1024x1024
image, which are physically masked and serve as a dark current
reference, are downlinked as subframe 0, even if the full image
case is described. Within the subframes, pixel binning as
described by mess:fpu_bin and mess:pixelbin is
performed.
Source of the 1 Hz time pulse used in
time-tagging MDIS images.
Commanded (lossy) wavelet compression ratio for
an MDIS image.