Guide star statistics

The mica.stats.guide_stats module includes code to gather acquisition and guide statistics data for each observation and return those data to the user.

To get the whole guide stats data table:

>>> from mica.stats.guide_stats import get_stats
>>> stats = get_stats()
>>> stats[(stats['obsid'] == 5438) & (stats['slot'] == 3)][0]['dy_std']
0.18406899294435713

The hdf5 in-kernel searches may be faster working with the table directly for some operations.

Data table fields

The guide statistics data table contains the following columns:

Column	Description
obsid	obsid
obi	observation interval number
kalman_tstart	Kalman transition tstart from kadi event
kalman_datestart	Kalman transition datestart from kadi event
npnt_tstop	tstop for end of NPNT dwell for this observation
npnt_datestop	datestop for end of NPNT dwell for this observation
revision	revision string representing the software version
slot	ACA readout slot id
idx	starcheck star catalog index id
type	star catalog type (BOT or GUI)
yang	commanded y-angle position for center of readout window (arcsec)
zang	commanded z-angle position for center of readout window (arcsec)
sz	image readout window size
mag	catalog MAG_ACA of acquisition star
n_samples	number of telemetry samples in Kalman (only samples with good telem quality)
n_track	number of samples with AOACFCT == ‘TRAK’
f_track	fraction of samples with AOACFCT == ‘TRAK’
f_racq	fraction samples AOACFCT == ‘RACQ’
f_srch	fraction samples AOACFCT == ‘SRCH’
f_none	fraction samples AOACFCT == ‘NONE’
n_kalman	number of tracked samples with no (modern) bad status flags set (no IR, SP)
no_track	fraction of no track samples (n_samples - n_track / n_samples)
f_within_0.3	fraction of tracked samples with 0.3 arcsecs of expected position
f_within_1	fraction of tracked samples with 1 arcsecs of expected position
f_within_5	fraction of tracked samples with 5 arcsecs of expected position
f_outside_5	fraction of tracked samples outside 5 arcsecs of expected position
f_obc_bad	fraction of tracked samples with modern bad status flags set (IR, SP)
f_common_col	fraction of tracked samples with AOACICC flag set to ERR
f_quad_bound	fraction of tracked samples with AOACIQB flag set to ERR
f_sat_pix	fraction of tracked samples with AOACISP flag set to ERR
f_def_pix	fraction of tracked samples with AOACIDP flag set to ERR
f_ion_rad	fraction of tracked samples with AOACIIR flag set to ERR
f_mult_star	fraction of tracked samples with AOACIMS flag set to ERR
aoacmag_min	min magnitude over interval
aoacmag_mean	mean magnitude over interval
aoacmag_max	max magnitude over interval
aoacmag_std	std of magnitude over interval
aoacyan_mean	mean AOACYAN
aoaczan_mean	mean AOACZAN
dy_min	dy min (see notes on residuals)
dy_mean	dy max (see notes on residuals)
dy_std	dy std (see notes on residuals)
dy_max	dy max (see notes on residuals)
dz_min	dz min (see notes on residuals)
dz_mean	dz max (see notes on residuals)
dz_std	dz std (see notes on residuals)
dz_max	dz max (see notes on residuals)
dr_min	dr min (see notes on residuals)
dr_mean	dr max (see notes on residuals)
dr_std	dr std (see notes on residuals)
dr_5th	dr 5th percentile value
dr_95th	dr 95th percentile value
dr_max	dr max (see notes on residuals)
n_track_interv	number of intervals of continuous track
n_long_track_interv	number of intervals of continuous track with > 60 samples
n_long_no_track_interv	number of intervals of continuous loss of track with > 60 samples
n_racq_interv	number of intervals during Kalman when RACQ was set for the slot
n_srch_interv	number of intervals during Kalman when SRCH was set
agasc_id	AGASC (catalog) id
color1	AGASC COLOR1, estimated B-V color
ra	Right Ascension, corrected for proper motion at obs time (degrees)
dec	Declination, corrected for proper motion at obs time (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
tccd_mean	mean CCD temperature over Kalman interval
tccd_max	max CCD temperature over Kalman interval
known_bad	ignore this star in standard processing (boolean)
bad_comment	reason to ignore a “known_bad” star

Notes on residuals:

• The dy, dz, dr values are residuals calculated by subtracting the expected star position from the telemetered star position (AOACYAN AOACZAN).

• The expected star position has been calculated using the onboard estimated attitude (AOATTQT*) and the AGASC RA/Dec for the commanded star.

• dr is defined as sqrt(dy**2 + dz**2)

Processing

For each observation, after the observation has run and telemetry is available, the guide stats process does the following:

• Fetches the AGASC information for each star in the catalog

• Fetches the PCAD data for the Kalman interval

• For each guide star in the Kalman interval star calculates statistics on metrics for that star over the interval.