The design and implementation of the 2MASS Pipeline Processing System (2MAPPS) is described in the 2MAPPS Functional Design Document . 2MAPPS is a highly modular system comprised of individual subsystems that each handle a well-defined phase of data processing. Overall, processing within 2MAPPS is a linear function in that the output from one subsystem is the input for the next.
The document below describes the parameters within each subsystem that require tuning for optimal operation with the 2MASS data. Within each section, The name, a brief description, and initial estimates for the value of each parameter are listed. At the beginning of each section, the names of the cognizant 2MASS Science Team members and Design Engineers for the subsystems are given. Where relevant, links are also provided to the Subsystem Design Specification Documents (SDS) that provide detailed explanations of each subsystem.
The goals are to 1) converge on a complete and prioritized, yet manageable
set of tunable parameters, 2) determine
reasonable initial estimates for those parameters, 3) determine what if any
further engineering test data should be acquired to perform the analysis
necessary to tune the parameters, and 4) ultimately to converge on appropriate
values for each parameter. Steps 1) and 2) are largely complete, less the
prioritization. Steps 1)-3) will be topics for discussion at the
November Science Team Meeting in Boston. The schedule for completion of step
4) coincides with the delivery of 2MAPPS v2.0 in February of 1998.
2. RD_FRAME
RD_FRAME is a subroutine called by by several other subsystems within 2MAPPS. Consequently, RD_FRAME's tunable parameters are actually parameters passed to it by other routines.
1)saturation values ; Currently single value per band. This will change to
256x256 FITS array per band.
saturat(j,h,k) = 43000., 43000., 43000.,
2) t1, t2 ; A pair of dates/times indicating the time range of
validity of the above.
3)in and cross scan sos/eos position offsets
xsoff1(j,h,k) = 0.0, 0.0, 0.0,
isoff1(j,h,k) = 0.0, 0.0, 0.0,
xsoff2(j,h,k) = 0.0, 0.0, 0.0,
isoff2(j,h,k) = 0.0, 0.0, 0.0,
4)Axis 1 and Axis 2 Pixel Size (degs) - for FITS headers
rcdelt1(j,h,k) = -0.0005589, -0.0005585, -0.0005541,
rcdelt2(j,h,k) = +0.0005562, +0.0005580, +0.0005536,
DARKS
Name Description Dim Type Units Default
--------- ------------------------------------ ---- ---- ----- -------
AndMsk If AndMsk(I,J) = T, then for band I 3,2 L - 6*T
and read-type J, the new and old
masks will be logically ANDed
DRLim Maximum number of pixels failing 3,2 I*4 - 6*25
the MaxRDif test for a responsivity
image to be accepted [1]
Max1Sat Maximum number of saturated pixels 3 I*4 - 3*200
in Read1 to accept Read2-Read1
frame for use in responsivity
computation (one per band)
Max2Sat Maximum number of saturated pixels 3 I*4 - 3*2000
in Read2 to accept Read2-Read1
frame for use in responsivity
computation (one per band)
MaxDfMn Maximum absolute mean of new-old 9,2 R*4 -/DN 3*0.003
pixel values for J/H/K responsivity, 6*10.0
J/H/K Read1 darks, and J/H/K Read2- 3*0.1
Read1 darks, respectively [2] 6*99.9
MaxDfSD Maximum sigma value of new-old 9,2 R*4 -/DN 3*0.005
pixel values for J/H/K responsivity, 6*25.0
J/H/K Read1 darks, and J/H/K Read2- 3*0.2
Read1 darks, respectively [2] 6*99.9
MaxMed Maximum permitted dark-subtracted 3 R*4 DN 3*27000
frame median to keep in stack for
responsivity calculation; one/band
MaxMEMn Maximum absolute mean of evening 9,2 R*4 -/DN 3*0.003
minus morning pixel values for 6*10.0
J/H/K responsivity, J/H/K Read1 3*0.1
dark, and J/H/K Read2-Read1 dark 6*99.9
images, respectively [2]
MaxMESD Maximum sigma value of evening 9,2 R*4 -/DN 3*0.005
minus morning pixel values for 6*25.0
J/H/K responsivity, J/H/K Read1 3*0.2
dark, and J/H/K Read2-Read1 dark 6*99.9
images, respectively [2]
MaxPass Maximum number of linear least- I*4 - 10
square passes per pixel allowed in
the responsivity calculation
MaxRDif Maximum absolute morning-evening 3,2 R*4 - 6*0.1
and new-canonical responsivity
difference for a pixel not to be
included in sum for DRLim test
(see above) [1]
MaxSD Maximum sigma value for a pixel's 3 R*4 DN 3*25.0
dark average for each band; pixel is
masked if exceeded
MinFrac Minimum fraction of raw pixel values R*4 - 0.3
to retain in final least-square pass
MinFrms Minimum number of usable frames to 3 I*4 - 3*30
proceed with responsivity computation
(one per band)
RngMin Minimum range in frame median to 3 R*4 - 3*20000
proceed with responsivity computa-
tion (one per band)
RspMax Maximum responsivity value in J/H/K; 3 R*4 - 3*2.0
if exceeded, pixel is turned off in
the corresponding masks
RspMin Minimum responsivity value in J/H/K; 3 R*4 - 3*0.5
if less, pixel is turned off in the
corresponding masks
SigRej Sigma rejection level for linear R*4 DN 2.0
least-square passes after the first
TrmFrac Fraction of total number of dark R*4 - 0.25
values for a pixel to be trimmed from
each end of sorted array before
averaging
Notes
[1] The first index in the (3,2) dimension is band (J, H, K), and the second
index has the value 1 for morning-evening differences and 2 for new-canonical
differences.
[2] The second index in the (9,2) dimension is a severity index; the first value
causes warning messages to be displayed if exceeded, the second causes DARKS to
return an error code of 4 after finishing its computations, which halts the
pipeline.
Name Description Dim Type Units Default
--------- ------------------------------------ --- ---- ----- -------
DLMax Maximum acceptable deviation from 2 R*4 - 10.0,
linearity of a pixel in an Sj image 50.0
with respect to time variation (in
units of the pixel's mean standard
deviation about its trimmed average
offset correction; if exceeded and
SetBlank = T, the pixel will be
turned off in the Sj image; the index
corresponds to read type
DSigMax Maximum non-anomalous sigma of 2 R*4 9.9e25,
linear fit of Sj pixel over time 9.9e25
(in noise units; see ZSigMax for
""); if above and GenMask = T,
pixel will be turned off in the mask;
index corresponds to read type
MaxBlnk Maximum no. of times a given pixel 1 I*2 - 3
may be blank in an Sj image before
it is turned off in the mask if
GenMask = T
NFrPerFl No. of frames between flat 1 I*4 - 44
computations
NFrWdth No. of frames to use to compute 1 I*2 - 42
an Sj image (stack size)
NRMDR Number of RMDR trims to do before 1 I*2 - 20
the symmetric trimming
NTrim No. of pixels to trim symmetrically 1 I*2 - 0
from each end of the sorted list of
stacked pixels before averaging them
SetBlank If T, Sj pixels will be set 1 L - T
blank if anomalous
SMax Maximum acceptable value of a pixel 2 R*4 DN 500,
in an Sj image; if exceeded and 500
SetBlank = T, pixel will be blanked
in that Sj image; index corresponds
to read type
SMin Minimum acceptable value of a pixel 2 R*4 DN -500,
in an Sj image; if not exceeded and -500
SetBlank = T, pixel will be blanked
in that Sj image; index corresponds
to read type
TSigMax Maximum non-anomalous sigma of 2 R*4 DN 9.9e25,
trimmed average in Sj computation; 9.9e25
If above and SetBlank = T, pixel
will be blanked in that Sj image;
index corresponds to read type
ZSigMax Maximum non-anomalous z-sigma of 2 R*4 4,4
trimmed average in flat computation;
"z-sigma" in units of "" means
a pixel's standard deviation relative
to the standard deviation averaged
over all non-masked pixels; pixels
over the ZSigMax threshold will be
turned off in the mask if GenMask=T
and TAStat=T; index corresponds to
read type
Read_1 and Read_1-Read_2 frame source extractions. Read_1 photometry. Frame statistics measurement. Frame offset estimation.
variable dim type default description
-----------------------------------------------------------------------------
mag0 2,3 R4 17.4 20.8 mag0(i,j) = template magnitude zero point
17.2 20.6 offset for read i of band j
16.5 19.9
amag0 2,3 R4 17.4 20.8 amag0(i,j) = aperture magnitude zero point
17.2 20.6 offset for read i of band j
16.5 19.9
doaph 2 L T T if doaph(i) = .true., call apphot for aperture
photometry for read i
par 14 R4 2.0 4.0 par(i)(i=1,12)= radii of aperture i.
12.0 15.0 par(13,14)= inner,outer radii for background
hibad 1 R4 32000.0 maximum valid ADU
phpadu 1 R4 10.0 gain (e-/ADU)
readns 1 R4 48.0 read noise (e-)
minrad 1 R4 3.0 minimun radius for apphot pixel fix-up
pfrac 1 R4 0.5 initial pfrac for pass 1
rpk 1 R4 0.3 maximum radius from peak for pfrac histo
in pixels
tpk 1 R4 20.0 minimum snr for pfrac histogram
prmax 1 R4 0.85 maximum peak ratio for pfrac histogram
thres 2,3 R4 15.0 10.0 thres(i,j) = extraction snr threshold for
15.0 10.0 read i of band j
15.0 10.0
siglo 1 R4 -1.0 noise is computed from difference in
sighi 1 R4 +1.0 gaussian percentiles of sighi and siglo
sigmed 1 R4 0.0 background is computed from gaussian
percentile of sigmed
nb2do 1 I4 3 if: nb2do = 1, process read 1 only
nb2do = 2, process read 2 only
nb2do = 3. process both reads
nb2do = 0. process neither read
psiga, 2,3 R4 6*0.6 modeled position error =
psigb 2,3 6*2.0 sqrt(psiga^2 + (psigb/snr)^2)
thrdmp 2,3 R4 4*50,2*30 dump 7x7 pixel patches for sources snr>thrdmp
*Also, psfs need to be generated over a range of seeing. This is currently
my highest priority.
|parm |current est.|Description |
--------------------------------------------------------------------------------
CONTROL PARAMETERS
mfrac .5 Match fraction required for GOOD pattern match
nrpmax ? Max number of reference peg-pair trys allowed
nepmax ? Max number of extraction peg-pair trys allowed
mxtry2 20 Max number of trys with same first reference peg allowed
mnmfor 10. Min ratio of matches found over expected random matches
drmch 3. asec Match acceptance radius
dxcan 90. asec Max x-scan search radius for peg-pair matching
dycan 90. asec Max in-scan search radius for peg-pair matching
ysepfr .33 Min in-scan separation of pegs in fractional scan length
maxjmv 1.5 mag Max magj-magv allowed for match
mxeovr 500. Max ratio of extractions over references used for
pattern match. Only the n brightest extractions are
used where n is determined from mxeovr.
dsymx .01 Max in-scan scale change from apriori allowed. Used to
limit search space.
necmx 100 Max number of extraction candidates used per reference peg.
Will consider the necmx brightest within the dxcan/dycan
window.
mintyc 4 Minimum number of tychos required in scan for fit
tcfrac .33 Tycho coverage fraction of scan length required for fit
sigap 5. asec Sigma on the three apriori pseudo points which tie
each frame to the next. Needed to bridge frames
without extractions.
wxbox 3. asec X-scan window used for merging extractions
wybox 3. asec In-scan window used for merging extractions
mxdpfrj 200 Max detections per frame in J-band used for reconstruction
mxdpfrh 200 Max detections per frame in H-band used for reconstruction
mxdpfrk 200 Max detections per frame in K-band used for reconstruction
chisqmx 32. Max ChiSq for final point source associations
INITIALIZATION PARAMETERS
cxr10 .0 asec READ1-READ2 x-scan difference
cyr10n .3 asec READ1-READ2 in-scan difference for northward scans
cyr10s -.2 asec READ1-READ2 in-scan difference for southward scans
cdxh2j 2.7 asec X-scan J-H difference at nf=0
mdxh2j ? as/nf Slope of x-scan J-H difference w.r.t. frame number
cdyh2j 3.4 asec In-scan J-H difference at nf=0
mdyh2j ? as/nf Slope of in-scan J-H difference w.r.t. frame number
cdxk2j -0.7 asec X-scan J-K difference at nf=0
mdxk2j ? as/nf Slope of x-scan J-K difference w.r.t. frame number
cdyk2j 1.4 asec In-scan J-K difference at nf=0
mdyk2j ? as/nf Slope of in-scan K-K difference w.r.t. frame number
wpxj 1.9971 asec J-band x-scan pixel width
wpxj 1.9971 asec J-band in-scan pixel width
dthej .388 deg J-band rotation angle w.r.t. scan direction
wpxh 2.0061 asec H-band x-scan pixel width
wpxh 2.0061 asec H-band in-scan pixel width
dtheh .451 deg H-band rotation angle w.r.t. scan direction
wpxk 1.9837 asec K-band x-scan pixel width
wpxk 1.9837 asec K-band in-scan pixel width
dthek .344 deg K-band rotation angle w.r.t. scan direction
dra0n -3.68 asec Bias in observatory est. of RA at northward scan start
dra0s -5.58 asec Bias in observatory est. of RA at southward scan start
ddec0n 156.34 asec Bias in observatory est. of Dec at northward scan start
ddec0s -177.14 asec Bias in observatory est. of Dec at southward scan start
xstepjn 0.49 asec J-band x-scan frame-to-frame step size for northward scans
xstepjs -0.48 asec J-band x-scan frame-to-frame step size for southward scans
istepjn 82.64 asec J-band in-scan frame-to-frame step size for northward scans
istepjs -82.64 asec J-band in-scan frame-to-frame step size for southward scans
MODEL PARAMETERS
-----------------------------------
Distortion model - TBD
Uncertainty model - TBD
POSPTS PARAMETERS
-----------------
Name Description Type Dim Units Default
------ ------------------------------------- ---- --- ------- --------
DXAB Coarse X window (ASOC/BMG matching) R*4 1 arcsec 3.0
DXMax Max abs mean N-Scan X offset to R*4 1 arcsec 0.3
accept first ASOC/BMG match set [1]
DXPB Coarse X window (PFMP/BMG matching) R*4 1 arcsec 3.0
DYAB Coarse Y window (ASOC/BMG matching) R*4 1 arcsec 3.0
DYMax Max abs mean N-Scan Y offset to R*4 1 arcsec 0.3
accept first ASOC/BMG match set [1]
DYPB Coarse Y window (PFMP/BMG matching) R*4 1 arcsec 3.0
ThrAB Threshold for ASOC/BMG match, pass 1 R*4 1 [2] - 25.0
ThrAB2 Threshold for ASOC/BMG match, pass 2 R*4 1 [2] - 25.0
ThrPB Threshold for PFMP/BMG match R*4 1 [2] - 25.0
XSigMx Max N-Scan X sigma of matched objects R*4 1 arcsec 2.0
to accept first ASOC/BMG match set [1]
YSigMx Max N-Scan Y sigma of matched objects R*4 1 arcsec 2.0
to accept first ASOC/BMG match set [1]
Notes
-----
1.) If any of the DXMax, DYMax, XSigMx, or YSigMx thresholds are exceeded
by the best-match pairs of associated sources after the first pass
through the catalog association loop, the associations are done over
from the beginning with the mean offsets in N-Scan X and Y from the
first pass subtracted out, and a separate threshold parameter (ThrAB2)
is used. This applies only to ASOC/BMG matching.
2.) Thresholds ThrAB, ThrAB2, and ThrPB are 2-D chi-square upper limits.
Assembles and registers Atlas Images from calibrated frames. Deep source detection.
variable type default description
-----------------------------------------------------------------------------
coff L T if = T, match frame background levels
nlino I 1024 # lines in full size coadded image
ncolo I 512 # columns in coadded image
dlpim F 970 # lines between coadded images
ncmin I 2 if < ncmin frames overlap a coadd pixel, set it blank
zroxof L T if = T, center coadds on x=0 Uscan coordinate
else center on data
solrad F 2.5 blanking radius for solos (camera pixels)
marzap L F if = T, mark zapped solos in coadds (debugging)
siglo F -1.0 Noise estimator uses the interval between the
sighi F 0.0 Gaussian percentiles of siglo,sighi /(sighi-siglo)
dethr F 3.0 Detection threshold (sigma)
fwhm F 4.0* FWHM of Gaussian filter used for detection
* should be a (TBD) function of seeing
readns F 5.0 Camera read noise (dn) - used for noise estimate
phpadu F 10.0 Camera gain (photons/dn) - used for noise estimate
nolap I 6 frame overlap depth - used for noise estimation
lobad F 10.0 Maximum valid sigma below background in input frames
hibad F 40000 Maximum valid dn in input frames
shrplo F 0.10 Minimum value of sharp parameter for valid detection
shrphi F 1.00 Maximum value of sharp parameter for valid detection
rndlo F -2.00 Minimum value of round parameter for valid detection
rndhi F 2.00 Maximum value of round parameter for valid detection
seep F 1.1 Value of seeing parameter (overridden by seeman)
wpc F 1.0 width of coadd pixeli (arcsec)
kernel A wkern Interpolation kernel type:
'wkern' - Weinberg kernel
'bilin' - Bilinear kernel
'aolap' - Area overlap kernel
'kerfil' - Read kernel from kerfil
' ' - kernel specified in namelist
hsmo F 0.35 smoothing length for Weinberg interpolation kernel
xpdel(ib) F 0.0 PSF cross-scan offset correction for band ib (pixels)
ypdel(ib) F 0.0 PSF in-scan offset correction for band ib (pixels)
A. Apphot Parmeters
Current
Name Value Description
1. SKYIN 7.0 pix Inner radius for sky annulus, within which
pixels are used for a clipped sky mean.
2. SKYOUT 10.0 pix Outer radius for sky annulus, within which
pixels are used for a clipped sky mean.
3. MINRAD 3.0 pix Radius outside of which bad pixels are
replaced with a reasonable PSF+sky value.
B. PSF fitting Parameters
Current
Name Value Description
1. RADIUS 2.0 pix Radius within which pixels are used in
the profile fitting process.
2. MASKYR 3.0 pix Radius within which all pixels near all
detected sources are masked from the sky
(background) determination routine.
3. THRESH 1% Fraction of PSF flux level that a detected
neighbor has at the center of a star before
two detections are profile-fit simultaneously.
4. ITER 100 Limit on the number of iterations for the
chi-squared minimization to achieve a solution.
C. Deblending Parameters
Current
Name Value Description
1. CHIP 5.0 Reduced chi-squared limit, above which a
single source may be "split" into two possible
sources.
2. XMAG 12.5 Magnitude limit for splitting sources; do not
split fainter sources.
3. NSOURCE TBD Density limit for splitting sources, the
(b<20) number of stars in a 6-frame overlap segment;
do not split sources in very dense regions.
4. WEIGHT2 0.2 Weighting function parameter applied to ratio
of peak pixel values in primary and secondary
sources to determine the preliminary
separation of double.
5. CHIP2 10000.0 Reduced chi-squared limit, above which a
double source may be "split" into three
sources.
C. PSF Manufacture Parameters
Current
Name Value Description
1. NSTARS 50 Number of bright (non-saturated) stars used
to make the PSF for a scan.
2. FWHM 1.2 pix FWHM of a Gaussian function used as a starting
point to extract PSFs, when selecting out
aberrant data such as doubles and galaxies.
3. SNMIN 50.0 Minimum acceptable S/N for a stellar image
as a PSF candidate.
4. DIFFMX 0.3 mag Maximum acceptable magnitude difference;
|PSF fit - aperture| .
5. CHIMAX 10.0 Maximum acceptable reduced chi squared for
a source fit.
Notes:
1) The unit of a "pix" comes from a frame pixel, being 2 arcsec on a side.
2) Several of the "Profile Fit" parameters are used by the PSF
Manufacture routines, for similarity in the handling of PSFs,
e.g. RADIUS and MASKYR.
Look-up table values:
---------------------
Read_1 magnitude normalization value & sigma
For each PSF:
aperture correction & sigma
PSF-fit magnitude normalization & sigma
Namelist values:
----------------
det_lim = j:17.0, h:16.5, k:16.0,
pt src detection limit mags, beyond which no artifact searches are made.
std_ap = 2.0,
The size of the "standard" aperture radius (in camera pixels) for the
standard aperture mag, to use for the aperture correction determination.
lg_ap = 5.0,
The size of the "large" aperture radius (in camera pixels) for the
large aperture mag to carry along; useful for possible extended srcs.
brstar_thr = j:10.5, h:10.0, k:9.5,
A source brighter than brstar_thr causes MAPCOR to
search for resulting bright-star artifacts.
starchi_thr = 6.0,
A source is considered a star (for MAPCOR's purposes)
if its PSF-fit chi^2 parameter from the Read2-Read1 source data file
is less than starchi_thr.
psfsrcs_min = 10,
A "PSF group" must have at least this many sources for calculating
aperture corrections and PSF-fit magnitude normalizations
n_rej = 2.0,
The number times the rms to use in the root-mean-square rejection
when iteratively calculating medians.
loss_max = 0.30,
The max fractional loss of srcs from rejection to allow when iteratively
calculating medians.
iter_max = 20,
The maximum number of iterations allowed in calculating medians.
del_med = 0.0005,
Iterative median calculation stops when
the change in the median drops below delmed.
n_check = 3.0,
When checking calculated values compared to lookup values, a warning is
generated if they don't agree to within +/- n_check*sigma.
satr1_c = j: 0.973, h: 0.886, k: 0.663,
satr1_d = j:-5.702, h:-4.385, k:-1.444,
A corrected magnitude for a saturated Read1 source
will be calculated by m_c = c * m_p1 + d,
where m_p1 is the magnitude of its first persistence source
in the Read1 source list
satr1_rms = j:0.443, h:0.601, k:1.11,
rms of real R1 mag vs. 1st persistence src mag relation, to be rss'ed
with the persistence src mag sigma to determine the new sigma value.
pers_nmin = 4,
min # of persistence srcs to search for
pers_nmax = 10,
max # of persistence sources to search for
chain_dens = 5000.0,
An unbroken chain of persistence sources may be required if
the source density (per sq. deg) of the scan is above chaindens,
to lessen the chance of real srcs being called persistence.
(npers) 1 2 3 4 5 6 7 8 9 10
pers_dm = j: 5.8, 7.6, 8.4, 8.8, 9.1, 9.4, 9.8, 11.0, 12.0, 13.0
h: 5.8, 7.6, 8.4, 8.8, 9.1, 9.4, 9.8, 11.0, 12.0, 13.0
k: 5.8, 7.6, 8.4, 8.8, 9.1, 9.4, 9.8, 11.0, 12.0, 13.0
pers_sigm = j: 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
h: 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
k: 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
A progression of predicted persistence sources
should be fainter in magnitude than the "parent" source by
the empirically determined series pers_dm(band,npers)
with uncertainties of pers_sigm(band,npers).
pers_r = 3.0,
pers_r is the persistence search radius (in pix)
pers_sigr = 1.0,
Predicted persistence locations have an empirically determined position
uncertainty pers_sigr from camera jitter and frame-to-frame offset
determination, which is used in the persistence chi^2 probability
calculation.
chi^2 = [(x_src - x_pred)/sig_x]^2 + [(y_src - y_pred)/sig_y]^2 +
[(m_src - m_pred)/sig_m]^2 ;
sig_x^2 = sig_x_parent^2 + sig_x_src^2 + pers_sigr^2 ;
sig_y^2 = sig_y_parent^2 + sig_y_src^2 + pers_sigr^2 ;
sig_m^2 = sig_m_parent^2 + sig_m_src^2 + pers_sigm^2 ;
which is then converted to a probability.
pers_pthr = 0.50,
If a persistence probability is above pers_pthr, the src is considered a
persistence src within MAPCOR when determining if it is a "good" src,
and keeping counts of artifacts.
(glint #) 1 2
glint_delm = j: 6.4,
h: 6.4,
k: 6.4, 6.4,
glint_sigm = j: 1.0,
h: 1.0,
k: 1.0, 1.0,
Filter glints have magnitudes that are glint_delm mag fainter than the
"parent" bright sources with an uncertainty of glint_sigm.
(glint #) 1 2
glint_e = j: 1.0,
h: 1.0,
k: 1.0, 1.0,
glint_f = j: 0.5,
h: 0.5,
k: 0.5, -2.0,
glint_g = j: 1.0,
h: 1.0,
k: 1.0, 1.0,
glint_h = j:-7.0,
h:-7.0,
k:-7.0, 8.0,
glint_r = j: 2.0,
h: 2.0,
k: 2.0, 2.0,
Filter glints are located at the positions x = glint_e*x + glint_f,
y = glint_g*y + glint_h
within an uncertainty radius of glint_r,
where (x,y) is the position of the "parent" source.
diffrlsc_dm = j:3.0, h:3.0, k:3.0,
If a source is located on a bright-star diffraction spike but is brighter
than m+diffrlsc_dm, where m is the bright star's magnitude, it will
be accepted as a real source but flagged as contaminated by the spike.
diff_width = j:2.5, h:2.5, k:2.5,
A diffraction spike has a predictable width diff_width.
diff_l0 = j:30., h:30., k:30.,
diff_m0 = j:7.0, h:7.0, k:7.0,
diff_a = j:0.1, h:0.1, k:0.1,
A diffraction spike has a predictable length
(the distance it extends out from the center of the bright source)
that is empirically modeled as l = diff_l0*{10^[diff_a(diff_m0-m)]},
where m is the "parent" source's magnitude.
diff_angle = j:0., h:0., k:0.,
diffraction spike angle to horizontal in deg.
diff_lmin = j: 1., h: 1., k: 1.,
diff_lmax = j:110., h:110., k:110.,
Calculated diffraction spike lengths are limited by diff_lmin and diff_lmax.
conf_r0 = j:2.0, h:2.0, k:2.0,
j:2.0, h:2.0, k:2.0,
conf_m0 = j:9.0, h:9.0, k:9.0,
j:9.0, h:9.0, k:9.0,
conf_b = j:0.125, h:0.125, k:0.125,
j:0.125, h:0.125, k:0.125,
A "parent" source's confusion radius
is empirically modeled as r = conf_r0*{10^[conf_b(conf_m0-m)]},
where m is the "parent" source's magnitude.
conf_rmin = j: 2.0, h: 2.0, k: 2.0,
j: 2.0, h: 2.0, k: 2.0,
conf_rmax = j:30.0, h:30.0, k:30.0,
j:30.0, h:30.0, k:30.0,
Calculated confusion radii are limited by conf_rmin and conf_rmax.
see_fact = j:0., h:0., k:0.,
To account for seeing effects, the confusion radius is root-sum-squared
with see_fact, a function (TBD) of band and the seeing parameter.
brap_thr = j: 8.0, h: 8.0, k: 8.0,
faap_thr = j:13.5, h:13.5, k:13.5,
A point source with a magnitude between brap_thr and faap_thr may be used
in calculating the aperture curve-of-growth and aperture correction.
del_conv = 0.015,
The aperture curve-of-growth converges when rho_i,
the median of m_i - m_{i+1}, is <=del_conv for a certain aperture i.
The value of 0.015 mag corresponds to the amount of the photometric error
budgeted for aperture corrections.
del_div = -0.0005,
The aperture curve-of-growth diverges when rho_{i-1} - rho_i <= del_div.
optap_max = 5.0,
The maximum "optimal" aperture (in camera pixels) allowed
in the aperture correction determination.
brpsf_thr = j: 8.0, h: 8.0, k: 8.0,
fapsf_thr = j:12.0, h:12.0, k:12.0,
A source with a PSF-fit magnitude between brpsf_thr and fapsf_thr may be
used for determining the normalization of the PSF-fit magnitudes
to the aperture-corrected aperture magnitudes.
r1_rad = 3.0,
r1_dm = 3.0,
A Read1 source and a Read2-Read1 source are an acceptable match in
the Read1 and Read2-Read1 merge if their positions are separated by
less than r1_rad and their magnitudes differ by less than r1_dm.
(r1_dm may become a function of Read1 magnitude, to account for
Read2-Read1 magnitude errors from saturation; now it is simply a
large value intended only to loosely constrain the Read2-Read1 match's
magnitude.)
r1mag_thr = j:9.0, h:9.0, k:9.0,
(Note: this parameter will probably be deleted
and the saturated pixel flag always used instead.)
If the Read1 magnitude is brighter than r1mag_thr,
the Read1 magnitude data should be used instead of
the matching Read2-Read1 source's magnitude data.
r1pos_thr = j:7.0, h:7.0, k:7.0,
(Note: this parameter might be deleted
and the saturated pixel flag always used instead.)
If the Read1 magnitude is also brighter than r1pos_thr,
the Read1 magnitude and position data should both be used instead of
the matching Read2-Read1 source's data.
brr1_thr = j: 8.5, h: 8.5, k: 8.5,
far1_thr = j:10.0, h:10.0, k:10.0,
A source with a Read1 magnitude
between brr1_thr and far1_thr may be used
for determining the normalization of the Read1 magnitudes
to the Read2-Read1 magnitudes.
Name Description Dim Type Units Default
--------- ------------------------------------ --- ---- ----- -------
ChSqMax Array of values for maximum allowed 2, R*4 [1] [1]
chi-square used to specify density- 10
dependent match thresholds
CnfVec Confusion coefficient vector for ? R*4 - [2]
dot product with status-flags
vector; added to chi-square test
parameter when confusion has been
diagnosed; see note [2]
ComFac Scale factor for threshold applied 1 R*4 - 1.5
to detections linked to a common
detection but not to each other
Density Array of source density values used 10 R*4 [1] [1]
to specify density-dependent match
thresholds
FChiSq Scale factor for position term in 1 R*4 - 1.0
the pseudo-chi-square formula used
for confusion match testing
FPh Scale factor for photometric term in 1 R*4 - 0.0
the pseudo-chi-square formula used
for confusion match testing
SigUx 1-sigma uncertainty in X due to error 3 R*4 arcsec 3*0.05
in mapping band-peculiar coordinates
SigUy 1-sigma uncertainty in Y due to error 3 R*4 arcsec 3*0.05
in mapping band-peculiar coordinates
to U-Scan coordinates, one per band
Notes
[1] The density-dependent threshold arrays are defined as follows.
ChSqMax(1,N) specifies the maximum allowed chi-square value for the source
density Density(N), where the latter is specified in total sources per square
degree in the two bands being tested, and the former applies to the unconfused
test. ChSqMax(2,N) is the corresponding value for the confused test, i.e., the
pseudo-chi-square. The arrays must be specified with Density(N) increasing as
N increases. The default values are as follows.
N Density ChSqMax(1,N) ChSqMax(2,N)
1 0 36.0 9.9e25
2 95000 36.0 9.9e25
3 100000 34.8 9.9e25
4 200000 17.4 9.9e25
5 300000 11.6 9.9e25
6 350000 10.0 9.9e25
7 9999999 10.0 9.9e25
8 9999999 10.0 9.9e25
9 9999999 10.0 9.9e25
10 9999999 10.0 9.9e25
[2] When confusion is diagnosed, the position-test chi-square parameter is
replaced with a pseudo-chi-square parameter that is a sum of the position-test
chi-square rescaled by FChiSq, a photometric chi-square scaled by FPh, and a
dot product of the CnfVec and Flags vectors, where CnfVec is user-specified,
and Flags is formed from various status parameters in the point-source record;
see Appendix D for a detailed description of the Flags vector, how it is used
with CnfVec, and the default values for the components of CnfVec.
General Parameters:
Mag limit for bright star blanking
Mask sizes for bright star blanking, including
diffraction spikes, persistence, horizontal stripes
& ghosts
{note: all are a function of the brightness of
the object and the confusion noise or equivalently the stellar
number density}
Variable mag thresholds for gal candidacy (function
of stellar density -- critical to processing efficiency
as the density becomes large)
Score thresholds, both preliminary and final thresholds
Algorithm 2: mag thresholds and BSNR thresholds
A more complete list of tunable parameters are given below:
--------------------------------------------------------------
deblend_density = 3.1 (default)
mag limits for gal candidacy (function of stellar num density)
Klim = 14.25
Hlim = 14.75
Jlim = 15.5
mag limits for star subtraction and blanking
mags limits for ellipse fitting; otherwise use "super" coadd vals
Klim_ellipt = 13.5
Hlim_ellipt = 13.9
Jlim_ellipt = 14.2
minima/maxima limits for profile fitting and scale length measurement
radmax = 15.0
radmin=4.0
radmax_elfit= 12.0
radmax_wedge=8.0
mag limit for bright star masking
brightlim = 9.0 (function of stellar num density)
other bright star masking parameters:
mask radius (function of star brightness, and stellar num density)
npersistence masks (function of star brightness)
diffraction spike length/width (function of star brightness)
horizontal stripe masks (function of star brightness)
mag limit for bright star processing (algor 3)
fraction area limit of bright galaxy processing
maximum size of known gal to process (diam in arcmin): BGALDIAM
minimum ratio between gal size and gal appearance on coadd: BGALRATIO
(i.e., at least 75% of gal must be on coadd)
BGALRATIO = 0.75
detection threshold (nsigma)
initial score thresholds
P_scorelim = score limit for preliminary mxdn scores
C_scorelim = score limit for mxdn, sh, & wsh tests
T_scorelim = score limit for trip killers: vmean, vint, sctrip
R_scorelim = score limit for r23
P_scorelim = 0.00
C_scorelim = 2.00
T_scorelim = 2.00
R_scorelim = 0.00
mag limits for star subtraction and blanking
radius of star subtraction / blanking (function of star brightness)
radius of isophotal substitution area
dx,dy from edge to work
Edge_lim = 10
stellar density limit at which to attemp galaxy deblends
deblend_density = 0.1
stellar density limit at which stars are blanked before ellipse fitting
ellfit_density = 3.5
mag limits at which to jettison K as fiducial
stellar density limit at which confusion noise is used instead of poisson noise
SNR limit at which to extract postage stamp
n-sigma contour for ellipse fitting (default = 3)
curve of growth convergence criteria
a) flux growth
b) stellar contamination
petrosian ratio to compute petrosian radius and flux
LSB detection thresholds
LSB mag limits
LSB SNR limits for star blanking
LSB blocked-snr limits for gal candidacy
LSB SNR limits for stamp extraction
blanking radius after object processed (function of curve of growth)
Name Description Default ----------------------------------------------------------------------------- DecBox Half-width DEC coarse matching window (half-width of 8.333e-3 deg. coarse RA window is calculated from this). ChiSqMx Chi-squared threshold value for minor planet - 2MASS 16.0 planet - 2MASS source match.
Name Default Description --------------------------------------------------------------------------- &acj = 0.0887 mag/am Slope of extinction correction j channel &ach = 0.0873 mag/am " h channel &ack = 0.0763 mag/am " k channel maxnrms = 0.04 mag Rms limit for nightly average maxlrms = 0.04 mag Rms limit for linear fit *maxlslp = 0.0083333 mag/hr .2/24 hr slope limit for linear fit *jmin = 11. mag Brightest j mag for smerge output - precal *jmax = 14. mag Faintest j channel for smerge output - precal *hmin = 10.5 mag Brightest h mag for smerge output - precal *hmax = 13.5 mag Faintest h mag for smerge output - precal *kmin = 10 mag Brightest k mag for smerge output - precal *kmax = 13 mag Faintest k mag for smerge output - precal *jbs = 3 mag Magnitude bin size for smerge - precal - j channel *hbs = 3 mag Magnitude bin size for smerge - precal - h channel *kbs = 3 mag Magnitude bin size for smerge - precal - k channel minfld = 3 mag Minimum number of calibration observations for night nsf = 38 Number of calibration tiles sstrf1='90004v1 90009v1 90013v1 90021v1 90067v1 90091v1 90121v1 90161v1 90191v1 90217v1 90234v1 90247v1 90273v1 90279v1 90290v1 90294v1 90301v1 90312v1 90533v1 90547v1 90565v1 90808v1 90860v1 90867v1 90868v1 90893v1 92026v1 92202v1 92397v1 90028v1 90023v1 90221v1 90330v1 90266v2 90565v1 90272v1 90182v1 90813v1' fldnm='FS4 Oph_n9a FS13 BRI0021-0214 M67 P091-D S121-E P161-D LHS191 S217-D S234-E P247-U S273-E S279-F P290-D S294-D S301-D S312-T P533-D L547 P565-C S808-C S860-D S867-V T868-53850 S893-D LHS2026 BRI2202-1119 LHS2397a FS28 FS23 P221-C P330-E P266-C P565-C P272-D P182-E S813-D' MINNFDSETS = 2 Minimum number of calibration field sets to make a calibration observation *MINNCS = 6 Minimum number of calibration scans in field to make a valid field set MAXSEP = 2.2 hours Time span between endtime of last calibration scan and beginning of next calibration scan *MAXDSPNSCN = .04 mag Maximum magnitude dispersion for all sources between same-field calibration scans *MAXDSPFD = .04 Maximum calib delta magnitude dispersion for all standards within calibration scan Other parameters which may need to be defined in addition to the above. exmaglk | | extinction calc. magnitude lower limit k band exmaguk | | extinction calc. magnitude upper limit k band exmaglj | | " " " lower limit j band exmaguj | | " " " upper limit j band exmaglh | | " " " lower limit h band exmaguh | | " " " upper limit h band * Values that may need to be tuned. & Values that need to be computed and require some effort look at several nights where a cal field was taken at a range of airmass and fit linear function to delta mag vs. airmass.
DB architecture (table fragmentation, etc.)
intervals at which data is loaded and re-indexed; update stats run
QA parameter threshold to determine whether a scan is "good"
For extended srcs -- which mags are "default" mags (see below); which
parameters to get rid of.
For each band, a "default" magnitude is selected by DBMAN and is used to
calculate the mag colors J-H,...R-K,...etc. For the "regular" ext. srcs,
the < b>_m values are the mags in each band at 20 mag/sq.arcsec w/fiducial
elliptical aperture (< b>_m_i20fe). If, however, this mag in any band is
> 75 (neg. flux or no mag found), the < b>_m values will be the mags from
fixed circular apertures with radii = 10 arcsec (< b>_m_10).
If one of these mags is > 75, the "default" mag
will be set to NULL.
For the LCSB srcs, the < b>_m values are the mags
from fixed circular apertures with radii = 10 arcsec (< b>_m_10). If one
of these mags is > 75, the "default" magnitude will be set to NULL.
If there is no detection of the src in one or two bands, the value
of the mag(s) in that band(s) is the band-fill aperture-photometry mag
(not yet available).
The < b>_msig fields contain the corresponding default mag sigmas.
1. Thresholds for 24-Hour Monitor
___________________________________________________________
Observation Date 970731n
-------------- pointing summary --------------
PctNpm (Percent failed position reconstruction) < 15%
Pointing:
AvDra (Average delta nominal RA to reconstructed) < 20.000
SigDra (RMS on above) < 15.000
AvDdec (Average delta nominal Dec to reconstructed) < 20.000
SigDdec (RMS on above) < 15.000
AvXSDif (Average X-Scan difference - south edge) < 10.000
SigXSDif (RMS on above) < 10.000
AvISMrg (Average In-Scan difference - either edge) > -10.000
SigISMrg (RMS on above) < 10.000
-------------- scanning summary --------------
Scanning:
dtheta (Average rotation angle) 0.250 - 0.350
sigthet (RMS on above) < 0.020
Offsets:
avyoff (Average in-scan step size) | 82.400| - | 82.800|
sigyoff is not tested.
avxoff is not tested.
sigxoff is not tested.
Tracking:
maxdra (Average max. delta reconstructed frame center to 1st frame) < 15.000
rmsdra_first (RMS on above) < 10.000
-------------- seeing/focus summary --------------
Avshape (Average image shape parameters) tested only if sigZP < 0.050
in which case Avshape < 1.10
OR 1.04 < FWHM_j / FWHM_h < 1.09
and
0.95 < FWHM_h / FWHM_k < 1.05
sigshape is not tested.
AvAspct (Average Moment Ratio) is not tested
MnAspct (Minimum Moment Ratio) > 0.900
MxAspct (Maximum Moment Ratio) < 1.100
-------------- photometric summary --------------
AvZP (Average photometric zero point offset) is tested only if sigZP > 0.050
in which case AvZP > -0.300
sigZP (RMS on above) < 0.050
---------- dark/responsivity summary ------------
diffdark (Average delta nightly & canonical dark frames) < 150.000
sigdark (RMS on above) < 150.000
Ndrkmask (Number pixels masked) < 2500
diffresp (Average delta nightly & canonical responsivity) < 0.010
sigresp (RMS on above) < 0.050
2. Scan Overlap Parameters
--------------------------------------------------------------------------
psf clearance angle = 4.0 arcsec
low coverage area = 428.0 arcsec at ends of scans
match radius = 2.0 arcsec
hi/low snr cutoff = 20.0 snr
number of bad frames= 2 (2 bad frames is max allowed)
persistence thresh. = .50 (if Tracey says % chance it's persistence)
3. Nightly Q/A Thresholds
--------------------------------------------------------------------------
4. Scan Q/A Thresholds
--------------------------------------------------------------------------
Last update - 3 September 1997
Roc Cutri - IPAC