RHESSI Quicklook Data products:

Observing Summary and Instrument Log

The Observing Summary is obtained directly from the telemetry packets. The photons are time-binned and the count rate is compressed to bytes (0.03 accuracy up to 1.0e6 counts/sec). Aspect solution, pointing, roll angle and roll period are given also. The nominal interval time for the count rates is the spin period of the spacecraft, 4 seconds, ephemeris info is given every 20 seconds , aspect info is given every second, roll period is given every 20 seconds.

The instrument log contains count rates summed over all energies for each detector, monitor rates, and packet rates, with 20 second time resolution.

Observing Summary objects

In the software, the data in the Observing Summary, the Flare List , and the Quicklook images and spectra are held in objects which are subclasses of the "Framework" object used for all HESSI objects. Thus the Qlook objects have the same data access methods as the other objects, Get and Getdata.

The Hsi_qlook objects are:

Hsi_obs_summ_rate -- contains spin-averaged count rates

Hsi_mod_variance -- The variance in the count rate in collimators 8 and 9.

hsi_ephemeris -- Spacecraft position

hsi_particle_rate -- particle rate

hsi_obs_summ_flags -- Various data flags

hsi_qlook_pointing -- Spacecraft pointing

hsi_qlook_roll_period -- Roll (spin) period

hsi_qlook_roll_angle -- Roll angle

hsi_flare_list -- Flare list

Contents of Individual objects

Each object contains its own info structure, and data structure. Each object can be read individually from the data file also, using getdata. If the data is already in the object, use the Get method.

IDL> rate_obj = obj_new('hsi_obs_summ_rate')

IDL> rate_data = rate_obj -> getdata(filename = filename, /all)

IDL> rate_info = rate_obj -> get(/info)

IDL> rate_data = rate_obj -> get(/data)

IDL> rate_data = rate_obj -> get(/control)

The Get method can be used to recall any control or info parameter as well.

Contents of the Individual Objects:

Hsi_obs_summ_rate

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
seg_index_mask = a bytarr(18) set to 1 for each detector segment that is used. Only 6 detectors are used -- detectors 2, 7, and 8 are not included.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 4 seconds.
n_energy_bands= the number of energy bands for the front detector count rates, hardwired to be 9
energy_edges = the energy bin edges, in KeV [3.0, 6.0, 12.0, 25.0, 50.0, 100.0, 300.0, 800.0, 7000.0, 20000.0]
dim1_unit = 'Energy edges (keV)' an identifying string
dim1_ids = The energy bins in string format

Data:

countrate = count rate, summed over detectors 1,3,4,5,6, and 9, in n_energy_bands energy bands, compressed cps.

Hsi_Mod_variance

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 4 seconds.
energy_edges = the energy bin edges, in KeV. [6.0, 25.0] is the default
variance_nbin = the number of time bins, per spin period, used to obtain the variance for detection of modulation. The default is 20.
dim1_unit = 'Collimator' an identifying string
dim1_ids = The collimator numbers in string format, ['8', '9']

Data:

mod_variance = a bytarr(2), for the two coarsest collimators the variance in the count rate for front detector elements, scaled by the poisson variance, then*10

Hsi_Ephemeris

Info:

n_time_intv = the number of ephemeris data points, for this summary
time_intv = the time interval between ephemeris recordings. Default is 20 seconds
ut_ref = Reference time for the ephemeris data.
dim1_unit = 'S/C position (km) and velocity (km/s)' an identifying string
dim1_ids = ['X', 'Y', 'Z', 'Vx', 'Vy', 'Vz']

Data:

xyz_eci = fltarr(6) of the spacecraft position in KM and velocity in KM/S, in ECI (Earth Centered Inertial) Coordinates. Note that this is to be considered as the position at the center time of each interval.

Hsi_obs_summ_flag

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 4 seconds.
nflags = the number of data flags, to a max of 32

flag_ids = string identifiers for each data flag,

                ['SAA_FLAG', $ ;1 for SAA, from orbit data
                 'ECLIPSE_FLAG', $ ;1 for Eclipse, 0 for sunlight, from orbit data
                 'FLARE_FLAG', $ ;1 for flare
                 'IDPU_CONTROL', $ ;IDPU version control number
                 'CRYOCOOLER_POWER', $ ;average for 4 sec interval
                 'COLD_PLATE_TEMP', $ ;average for 4 sec interval
                 'FRONT_RATIO_1225', $ ;front-total count rate ratio for 12 to 25 keV
                 'COLD_PLATE_SUPPLY', $ ;percent on for 4 sec interval
                 'HV28_SUPPLY', $ ;percent on for 4 sec interval
                 'ACTUATOR_SUPPLY', $ ;percent on for 4 sec interval
                 'FAST_HOUSEKEEPING', $ ;percent on for 4 sec interval
                 'SC_TRANSMITTER', $ ;(may affect detector 8), percent on for 4 sec interval
                 'SC_IN_SUNLIGHT', $ ;percent on for 4 sec interval, from packets
                 'SSR_STATE', $ ;0-8 SSR fill level, average for 4 sec interval
                 'ATTENUATOR_STATE', $ ;0,1,2,3, average for 4 sec interval
                 'FRONT_RATIO', $ ;Front counts /(front+rear), flare diagnostic
                 'NON_SOLAR_EVENT', $ ;set to 1 for a non-solar event
                 'GAP_FLAG', $ ;1 if no count rate data
                 'DECIMATION_ENERGY', $ ;energy channel upper limit for decimation
                 'DECIMATION_WEIGHT', $ ;decimation multiplier true_rate=weight*obs_rate
                 'MAX_DET_VS_TOT', $ ;fraction of counts in 1 detector,to rule out 1 detector flares
                 'NMZ_FLAG', $ ;Set to 1 if in North High-latitude Magnetic Zone
                 'SMZ_FLAG', $ ;Set to 1 if in South High-latitude Magnetic Zone
                 'AAZ_FLAG', $ ;Set to 1 if in the Atmospheric Absorption Zone
                 'PARTICLE_FLAG', $ ;Set to 1 for a Particle Event
                 'REAR_DEC_CHAN/128',$ ;Channel below which rear segment counts are decimated divided by 128.
		 'REAR_DEC_WEIGHT', $ ;rear decimation multiplier true_rate=weight*obs_rate
		 'PARTSTORM', $ ;particle storm
                 'HLAT', $ ;high latitude
                 'ECLIPSE_EXT', $ ;another eclipse flag, can be different from 'ECLIPSE_FLAG', which is obtained from the GDS.
                 'FRONTS_OFF', $ ;Front detector events are turned off 
		 'BAD_PACKETS'] ;Bad packets present in data

Data:

flags = a bytarr(32) of data flags

hsi_qlook_pointing

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 1 second.
n_sample = number of smaller bins per time_intv
A1 = 10.0, scaling factor real_data = a1*byte_data+a0
A0 = -1280.0
dim1_unit = 'Image Axis' an identifying string
dim1_ids = ['X', 'Y']

Data:

pointing = bytarr(2), Scaled SC pointing
quality = The SAS_ERROR, the square root of the average size of the reduced SAS triangle, in arcsec

hsi_qlook_roll_period

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 20 seconds.
n_sample = number of smaller bins per time_intv
A1 = 1.0, scaling factor real_data = a1*data+a0, roll_period is not byte-scaled.
A0 = 0.0
dim1_unit = 'Roll Period' an identifying string
dim1_ids = ['T_roll']

Data:

roll_period = SC roll_period

hsi_qlook_roll_angle

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 1 second.
n_sample = number of smaller bins per time_intv
A1 = 2*PI*255.0, scaling factor real_data = a1*byte_data+a0
A0 = 0.0
dim1_unit = 'Roll Angle' an identifying string
dim1_ids = ['T_roll']

Data:

roll_angle = Scaled SC roll_angle

hsi_flare_list See also http://sprg.ssl.berkeley.edu/~jimm/hessi/hsi_flare_list.html.

Info:

n_flares = The number of flares
list_start_time = the list start time, in a string, ccsds format e.g., 1998-08-16T17:05:00.000Z
list_end_time = the list end time, in a string, ccsds format e.g., 1998-08-16T19:05:00.000Z
energy_range_found = the energy range used to find the flares, in keV, the default is to use 12 to 25 keV.
nflags = the number of data flags, to a max of 32

flag_ids = string identifiers for each data flag, e.g.,

                 ['SAA_AT_START', $ ; 1 if saa_at_start
                  'SAA_AT_END', $ ; 1 if saa_at_end
                  'SAA_DURING_FLARE', $ ;1 if saa_during_flare
                  'ECLIPSE_AT_START', $ ;1 if flare starts at end of eclipse
                  'ECLIPSE_AT_END', $;1 if flare ends at start of eclipse
                  'ECLIPSE_DURING_FLARE', $ ;1 if eclipse during flare
                  'FLARE_AT_SOF', $;1 for flare at start of file
                  'FLARE_AT_EOF', $;1 for flare at end of file
                  'NON_SOLAR', $ ;1 for non-solar event
                  'FRONT_DECIMATION', $ ;set to 1 if decimation is present
                  'REAR_DECIMATION', $ ;set to 1 if decimation is present
                  'ATT_STATE_AT_PEAK', $ ;0,1,3
                  'DATA_GAP_AT_START', $
                  'DATA_GAP_AT_END', $
                  'DATA_GAP_DURING_FLARE', $
		  'PARTICLE_EVENT', $ ;set in the presence of particles > 3 per sec
		  'POSITION_QUALITY', $ ;set to 1 if position is ok
		  'ATTEN_0', 'ATTEN_1', 'ATTEN_2','ATTEN_3', $; set to 1 if that attenuator state is present
		  'MAGNETIC_REGION', $;set to 1 if at high magnetic latitude
                  'DATA_QUALITY', $ ;totals all the 1's for SAA, Eclipse, Data_gap, particles and decimation
		  'IMAGE_STATUS', $ ;set to 1 if the Qlook images for this flare have been done.
		  'SPECTRUM_STATUS'] ;set to 1 if the Qlook spectra for this flare have been done.

simulated_data = Flag set to 1 if the data is a simulation

Data:

id_number = An ID number,
start_time = flare start time, ANYTIM format, i.e., seconds from 1-Jan-1979 0:00 UT.
end_time = flare end time, ANYTIM format.
peak_time = flare peak time, ANYTIM format.
bck_time = Background accumulation time range, ANYTIM format.
image_time = time range for position & qlook images
energy_range_found = the energy range used to find flares
energy_hi = Edges of highest energy band of observed data.
peak_countrate = peak count rate
bck_countrate = background count rate
total_counts = total # of counts
peak_correction = Correction factor for peak counts, divide by this to get true observed counts
total_correction = Correction factor for total counts, divide by this to get true observed counts
position = flare position in arcsec from sun center
filename = file(s) which have the data for this flare, separated by commas
flags = a bytarr(32) of flare flags
seg_index_mask = a bytarr(18), set to 1 for the detector segments used to find the flare
sflag1 = 0 for non-solar, 1 for solar
active_region = Active region number, if available
goes_class = GOES Class, if observed

hsi_qlook_rate_per_det:

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 20 seconds.
dim1_unit = an identifying string
dim1_ids = The segment ids, '1f', '2f', etc...

Data:

countrate = the compressed count rate, each detector, summed over all energies

hsi_qlook_monitor_rate:

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 20 seconds.
dim1_unit = an identifying string
dim1_ids = ['PARTICLE_RATE', 'PREAMP_RESET', 'SHAPER_VALID', 'SHAPER_OVER_ULD', 'DELAY_LINE_VALID','LIVE_TIME']

Data:

particle_rate = hi, lo energy particle count
preamp_reset = Preamp reset count, each segment
shaper_valid = 4musec Shaper Valid Event Count, each segment
shaper_over_uld = 4musec Shaper over ULD Event Count, each segment
delay_line_valid = Delay Line valid event count, each segment
live_time = fraction of live time, each segment

hsi_qlook_packet_rate:

Info:

ut_ref = Reference Time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
n_time_intv = the number of time intervals, for this summary
time_intv = the nominal duration, in seconds, of a single time interval. Set to 20 seconds.
app_id = app_id for each packet type
dim1_unit = 'APP_ID'
dim1_ids = string(app_id)

Data

packet_rate = the rate in packets / second

hsi_qlook_summary_page:

Info:

n_pages = number of pages, 1 per orbit in the input interval
start_time = start time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.
end_time = end time, ANYTIM format, i.e., seconds from 1-jan-1979 0:00 UT.

Data is a string array

Accessing Observing Summary Data from the individual objects

The Observing Summary data is most easily accessed using the HSI_OBS_SUMMARY object. Here in this document we discuss how to deal with the individual objects contained in the HSI_OBS_SUMMARY object. To get an individual object from the obs_summary object, use the get(/object_reference) method, for example:

IDL> t = ['4-sep-2002 0:00','4-sep-2002 1:00']

Then

IDL> obj = hsi_obs_summary(obs_time_interval = t)

IDL> data = obj -> getdata(class_name='hsi_obs_summ_rate')

IDL> obs_summ_rate_obj = obj -> get(class_name='hsi_obs_summ_rate', /Object_reference)

Control Parameters

All of the hsi_qlook objects have the same control structure, To access : obj ->get(/control)

Class_name = 'HSI_OBS_SUMM_RATE' ; (for example) the class of the structure, this supercedes the class_name in the Framework object
version = version number
ID_string = an identifying string
vers_info = Version number for the info structure
vers_data = Version number for the data structure
obs_time_interval = the observation time interval, ANYTIM format
filename = the filename
absolute_time_range = time range for the data, ANYTIM format
ut_ref = a reference time, ANYTIM format
time_range = time_range relative to ut_ref

There are 6 control parameters for specifying the time range for the data returned in the Qlook object. Control parameters can be set in the initialization statement, or by using the Set method, or in the getdata statement. For any of these objects, either obs_time_interval or filename must be set, if not then a -1 is returned. See below for an example.

Archived data: obs_time_interval

If obs_time_interval is set, then the databaseis accessed and the data is otained from the data files in the directory which is pointed to by the env variable HSI_CATALOG_ARCHIVE. (See instructions on how to get test data and set up a data archive. ) This can be changed by setting the data_dir keyword in the getdata call to the appropriate directory.

Obs_time_interval is a two element array if time, in any ANYTIM readable format, for example:

IDL> t = ['4-jul-2000 0:00','4-jul-2000 1:00']

Then

IDL> obj = obj_new('hsi_obs_summ_rate', obs_time_interval = t)

IDL> obj = hsi_obs_summ_rate(obs_time_interval = t)

Then

IDL> data = obj -> getdata()

Or just

IDL> obj = obj_new('hsi_obs_summ_rate')

IDL> data = obj -> getdata(obs_time_interval = t)

will return the countrate data for the time range from 0:00 to 1:00 on 4-jul-2000. If the data is not in the archive, then -1 is returned.

We expect that most data access will be via obs_time_interval, but you can also access the data using the filename parameter. This should almost never be needed

Non-Archived Data: filename

If the filename is set, then the data will be read in from that file. Note that the filename parameter is not looked at if obs_time_interval is set, if both filename and obs_time_interval are set, then the data will be read from the archive. When passing in a filename, the full path for the file is necessary.

The control parameters all , and time_range are only used if filename is set. If all is set, then all the data from the given file is input. The data time range can be specified by the parameter time_range , which is a 2-element vector of times in ANYTIM format.

IDL> obj = hsi_obs_summ_rate()

IDL> obj -> set, filename = 'hsi_000.fits'

IDL> t = ['4-jul-2000 0:00','4-jul-2000 1:00']

IDL> data = obj -> getdata(time_range = t)

Time Arrays

Data times are not saved with the observing summary, but they can be obtained using Get, e.g.,

IDL> data_times = obs_summ_obj -> get(/time_array)

returns the time array for the given observing summary. This is to be interpreted as the interval start time for each interval, for the interval center time, which is what you will want to use if you are interpolating count rates, for example, or for the ephemeris data, set the /center keyword:

IDL> data_times = obs_summ_obj -> get(/time_array, /center)

Hsi_obs_summ_flag object

Unlike the other Obs summary objects, the Hsi_obs_summ_flag object contains more than one kind of data. To access a given data flag, use the flag_name keyword and the Get method:

IDL> obs_summ_flag_obj = hsi_obs_summ_flag(obs_time_interval = '...')

IDL> flag_data = obs_summ_flag_obj -> getdata()

IDL> saa_flag = obs_summ_flag_obj -> get(flag_name = 'saa_flag')

The different data flags are listed above.

The flag_name keyword also works for the hsi_flare_list object; if you want to see what flares in the object have the SAA in the flare interval, do:

IDL> flare_list_obj = hsi_flare_list(obs_time_interval = '...')

IDL> flag_data = flare_list_obj -> getdata()

IDL> saa_flag = flare_list_obj -> get(flag_name = 'saa')

The Plot Method

Each object (except for the flare list object) has a plot method associated with it. After the getdata is called, just do

IDL> obs_summ_obj -> plot

For the hsi_obs_summ_flag object, use the flag_name keyword for the individual flags , e.g., to plot the attenuator state,

IDL> obs_summ_flag_obj -> plot, flag_name='attenuator_state'

16-Oct-2004, jmm