Acquisition star statistics
---------------------------
The :mod:`mica.stats.acq_stats` module
includes code to gather acquisition star statistics data for each observation and
return those data to the user.
To get the whole acquisition table data:
>>> from mica.stats.acq_stats import get_stats
>>> stats = get_stats()
>>> stats[(stats['obsid'] == 5438) & (stats['slot'] == 1)][0]['dy']
8.4296239297976854
The hdf5 in-kernel searches may be faster working with the table directly for some
operations.
Data table fields
^^^^^^^^^^^^^^^^^
The acquisition statistics data table contains the following columns:
=============== ====================================================================
Column Description
=============== ====================================================================
obsid obsid
obi observation interval number
acq_start acquisition datestart from kadi event
guide_start guide transition datestart from kadi event
guide_tstart guide transition start from kadi event in Chandra secs
one_shot_length one shot delta quaternion arc length for this obsid manvr (arcsec)
revision revision string representing the software version
slot ACA readout slot id
idx starcheck star catalog index id
type star catalog type (BOT or ACQ)
yang commanded y-angle position for center of readout window (arcsec)
zang commanded z-angle position for center of readout window (arcsec)
halfw acquisition search box half width (arcsec)
mag catalog MAG_ACA of acquisition star
acqid acquisition success indicator (boolean)
star_tracked something tracked within 5 arcsecs during acq interval (boolean)
spoiler_tracked something tracked outside 5 arcsecs during acq interval (boolean)
img_func image status at transition: can be 'NONE', 'star', 'spoiler', 'RACQ', 'SRCH'
n_trak_interv number of intervals during acq when something was tracked
max_trak_cdy max "corrected" delta-y during acquisition (arcsec)
mean_trak_cdy mean "corrected" delta-y during acquisition (arcsec)
min_trak_cdy min "corrected" delta-y during acquisition (arcsec)
max_trak_cdz max "corrected" delta-z during acquisition (arcsec)
mean_trak_cdy mean "corrected" delta-z during acquisition (arcsec)
min_trak_cdz min "corrected" delta-z during acquisition (arcsec)
max_trak_mag max observed magnitude during acquisition
mean_trak_mag mean observed magnitude during acquisition
min_trak_mag min observed magnitude during acquisition
cdy "corrected" (see below) delta-y at guide transition. (arcsec)
cdy "corrected" (see below) delta-z at guide transition (arcsec)
dy delta-y at guide transition. expected position (see below) determined using onboard est. attitude (arcsec)
dz delta-z at guide transition. expected position (see below) determined using onboard est. attitude (arcsec)
ion_rad ionizing radiation flag set at transition (boolean)
def_pixel defective pixel flag set at transition (boolean)
mult_star multiple star flag set at transition (boolean)
sat_pix saturated pixel flag set at transition (boolean)
mag_obs observed magnitude at transition
yang_obs observed y-angle at transition (arcsec)
zang_obs observed z-angle at transition (arcsec)
agasc_id AGASC (catalog) id
color1 AGASC COLOR1, estimated B-V color
ra AGASC right ascension (degrees)
dec AGASC declination (degrees)
epoch AGASC EPOCH
pm_ra AGASC PM_RA, proper motion in ra (milli-arcsec/year)
pm_dec AGASC PM_DEC, proper motion in dec (milli-arsec/year)
var AGASC VAR, known or suspected variable star
pos_err AGASC POS_ERR, position error (milli-arcsec)
mag_aca AGASC MAG_ACA, ACA mag
mag_err AGASC MAG_ERR, (to be fixed, this should have been MAG_ACA_ERR)
mag_band AGASC MAG_BAND, integer code for spectral band
pos_catid AGASC POS_CATID, integer code for position catalog
aspq1 AGASC ASPQ1, integer spoiler code
aspq2 AGASC ASPQ2, integer proper motion flag
aspq3 AGASC ASPQ3, integer dist in 100m-arcsec to nearest Tycho2 star
acqq1 AGASC ACQQ1, mag diff to brightest star within 53.3" (0.01mags)
acqq2 AGASC ACQQ2, mag diff to brightest star within 107" (0.01mags)
acqq4 AGASC ACQQ4, mag diff to brightest star within 267.5" (0.01mags)
n100_warm_frac estimated n100 fraction of CCD pixels for this observation
ccd_temp mean CCD temperature over 500 seconds surrounding guide transition
known_bad ignore this star in standard processing (boolean)
bad_comment reason to ignore a "known_bad" star
=============== ====================================================================
Note that dy/dz are observed yag/zag (t_guide) - predicted yag/zag (t_guide) using AOATTQT
(estimated attitude). Observed yag/zag are from AOAC{Y,Z}AN, and t_guide is the time of
the first sample with AOACASEQ = 'GUID'. t_guide is the same as manvrs.guide_start in
kadi. The one-shot attitude update occurs in telemetry on the sample after the GUID
transition. In particular, dy/dz are used in the check for wrong box acquisition anomaly
as the the estimated attitude for dy/dz gives a reasonable approximation of the
OBC estimated attitude at the time of commanding the search boxes. (though the estimated attitude at
t_acq would be even better for that)
For the columns that reference "corrected" y-angle and z-angle, cdy/cdz, these are the
observed yag/zag (t_guide) - predicted yag/zag (t_guide) using the estimated attitude at
that time transformed/corrected by the one-shot quaternion (which is actually calculated from the
*next* one or two samples).
Processing
^^^^^^^^^^
For each observation, after the observation has run and telemetry is available, the
acquisition and guide stats process does the following:
* Fetches the AGASC information for each star in the catalog
* Fetches the PCAD data at the end of the acquisition interval
* For each acquisition star determines:
* If that star was "successfully" acquired
* What the observed magnitude and position of the star were in the last PCAD telemetry
readout before the guide transition.