USNO Magnitudes versus calibrated

Using Arne Henden photometric files, we began a comparison between USNO magnitudes and calibrated magnitudes.

For each calibrated star, we search for the matching star in the USNO-A2 catalog, using a tolerance on the order of 2 arcsec.

Inside each field, we perform a linear regression between the corresponding magnitudes, in B and R band, we reject outliers and iterate.

An obvious trend appears in the data, on the order of 0.1 mag/mag. As stars go fainter, USNO-A2 reports too bright magnitudes.

For each field the table contains:

Fields sorted by RA
#Field Name   --RA--- --DC--- Err_B Slope_B Err_R Slope_R
QR_AND       00h19.7m +2149' -0.15 -0.1110 +0.20 -0.1289 
TU_CAS       00h23.8m +2926' +0.08 -0.1701 -0.02 -0.0384 
SW_AND       00h23.8m +2927' +0.09 -0.1742 -0.02 -0.0406 
XX_AND       01h17.3m +3857' -0.44 -0.1143 +0.17 -0.0811 
SN2002AP     01h36.3m +1545' -0.31 -0.1142 +0.16 -0.1043 
AR_AND       01h45.1m +3757' +0.15 -0.2057 +0.39 -0.2099 
G4686        01h51.1m -0333' -0.15 -0.1522 +0.14 -0.0866 
RJ0151       01h51.3m -0224' -0.34 -0.0941 -0.06 -0.0814 
GRB000911    02h18.6m +0744' -0.36 -0.0074 -0.27 +0.0072 
RW_PER       04h20.4m +4219' -0.10 -0.0720 +0.07 -0.0336 
NOVA         04h21.2m +1626' -0.98 +0.0757 -0.62 +0.1307 
STHA32       04h37.8m -0119' -0.24 -0.0669 -0.11 -0.0161 
SN99EM       04h41.5m -0250' -0.85 -0.0164 +0.05 -0.1202 
SA96         04h51.4m -0011' -0.19 -0.1471 +0.22 -0.0471 
RXJ0459      04h59.7m +1928' -0.27 -0.0220 +0.23 -0.0186 
G1851        05h26.4m +2451' -0.54 -0.0264 +0.31 -0.0533 
G1852        05h27.5m +2540' -0.34 -0.0402 +0.29 -0.0554 
V650_ORI     05h31.2m +0946' -0.22 -0.0741 -0.24 +0.0119 
GD71         05h52.5m +1554' +0.33 -0.1730 -0.25 -0.0381 
GRB0307      05h56.3m +0757' -0.29 -0.0996 +0.13 -0.0380 
SA97         05h57.8m +0015' -0.39 -0.0111 +0.22 -0.0276 
UY_MON       06h15.3m +1531' -0.40 -0.0329 +0.19 -0.0568 
V344_ORI     06h15.4m +1531' -0.40 -0.0329 +0.19 -0.0568 
OW_GEM       06h31.7m +1705' +0.11 -0.1249 -0.18 +0.0203 
GRB0429      06h33.3m -0425' +0.15 -0.1716 +0.14 -0.0421 
G1014E       06h51.1m +1137' -0.27 -0.0959 -0.26 -0.0035 
AK_GEM       06h55.0m +1342' -0.13 -0.1117 -0.15 -0.0223 
UY_MON       06h58.8m +0938' -0.15 -0.1321 +0.07 -0.0330 
TZ_AUR       07h03.8m -0351' -0.18 -0.1207 +0.23 -0.0406 
NMON02       07h03.9m -0352' -0.16 -0.1280 +0.22 -0.0424 
NMON02       07h04.1m -0352' -0.20 -0.1053 +0.21 -0.0228 
XZ_CMI       07h04.2m -0352' -0.19 -0.0838 +0.23 -0.0077 
GRB010324    07h11.1m +2005' -0.55 -0.0431 +0.12 -0.0691 
TZ_AUR       07h11.8m +4048' -0.20 -0.0631 +0.21 -0.0668 
WX_CMI       07h11.9m +0730' -0.59 -0.0051 -0.26 -0.0307 
RU149        07h24.2m -0032' -0.28 -0.0744 -0.14 -0.0231 
NPUP00       07h38.0m -2557' -0.39 -0.0114 -0.13 -0.0321 
QX_PUP       07h42.3m -1443' -0.02 -0.1006 +0.02 -0.0730 
XZ_CMI       07h54.0m +0339' -0.33 -0.0359 -0.01 -0.0393 
SA99         07h56.0m -0017' -0.10 -0.0334 +0.16 -0.0380 
RU149        07h56.1m -0017' -0.11 -0.0358 +0.15 -0.0320 
DW_CNC       07h58.9m +1617' +0.13 -0.1396 +0.23 -0.1021 
GRB000115    08h03.5m -1714' +0.03 -0.1081 -0.28 -0.0085 
HS448        08h13.7m -0114' -0.10 -0.1468 +0.04 -0.0728 
SA124        08h18.8m -1541' -0.55 -0.0996 -0.25 +0.0017 
SA52         08h30.8m +2917' -0.43 -0.0614 -0.25 -0.0248 
GRB000115    08h35.2m +2828' -0.22 -0.1299 -0.08 -0.0979 
SN2001BG     08h35.3m +2828' -0.22 -0.1299 -0.08 -0.0979 
SA99         08h40.4m -1448' -0.34 -0.0557 +0.14 -0.1273 
NSV4189      08h40.5m -1448' -0.34 -0.0556 +0.14 -0.1268 
SA99         08h51.4m +1147'  0.00 -0.1244 +0.18 -0.1056 
M67          08h51.4m +1148' -0.01 -0.1158 +0.19 -0.0890 
RW_CNC       09h18.9m +2904' +0.17 -0.1262 +0.15 -0.0692 
SN2001BG     09h32.2m +2129' +0.07 -0.1212 +0.08 -0.0239 
NGC2903      09h32.2m +2130' +0.07 -0.1212 +0.08 -0.0239 
DV_UMA       09h46.5m +4447' -0.02 -0.1150 -0.24 -0.1461 
NGC3184      10h18.3m +4127' +0.19 -0.1458 +0.23 -0.1339 
WILUMA1      10h29.8m +3957' +0.33 -0.1617 +0.16 -0.1154 
NGC3432      10h52.6m +3639' -0.04 -0.0887 -0.09 -0.0563 
G45_20       10h56.6m +0702' +0.46 -0.2050 +0.37 -0.1710 
G2681005     11h03.7m +0711' -0.03 -0.1211 +0.22 -0.1337 
LEO2         11h13.6m +2209' -0.27 -0.0755 +0.00 -0.0661 
G010326B     11h24.4m -1109' +0.18 -0.1659 -0.07 -0.0110 
G010326A     11h24.4m -1110' +0.26 -0.1907 +0.03 -0.0667 
G010326A     11h51.1m -2332' +0.59 -0.2677 +0.40 -0.1073 
SA103        11h56.8m -0026' -0.07 -0.1159 +0.23 -0.1094 
W_COM        12h22.2m +2808' -0.72 -0.0557 -0.70 -0.0163 
GRB0418      12h25.4m +2006' -0.17 -0.1614 -0.17 -0.0761 
NGC4462      12h29.4m -2311' -0.03 -0.0212 -0.06 +0.0027 
CVN0662      12h32.7m +2702' +0.09 -0.2118 +0.05 -0.0827 
G3018        12h33.1m +3756' -0.47 -0.0021 -0.22 +0.0316 
G3018        12h33.2m +3757' -0.44 -0.0181 -0.20 +0.0273 
G3018        12h33.2m +3758' -0.44 -0.0181 -0.20 +0.0273 
TX_CVN       12h44.3m +3643' -0.28 -0.0793 -0.23 -0.0195 
GRB001105    13h02.0m +3529' +0.13 -0.1016 -0.11 -0.0566 
G020331      13h16.4m -1756' -0.13 -0.1296 +0.23 -0.0494 
HV_VIR       13h21.0m +0154' -0.23 -0.0906 +0.05 -0.0353 
GRB920517    13h33.3m -1642' -0.20 -0.0985 -0.10 +0.0041 
CVN0725      13h45.1m +3241' -0.46 -0.0867 -0.31 +0.0274 
GRB0313      13h50.1m +3118' -0.12 -0.1245 -0.21 +0.0176 
GRB0630N     14h47.3m +4119' +0.07 -0.1506 -0.08 -0.0055 
CVN0900      15h22.4m +2653' -0.57 -0.0520 -0.58 +0.0117 
QW_SER       15h26.2m +0818' -0.53 -0.0795 -0.07 -0.0556 
CVN0920      15h30.7m +3547' -0.02 -0.1367 +0.27 -0.0541 
CVN0902      15h47.8m +2725' -0.58 -0.0957 +0.21 -0.0829 
G2038        16h10.1m +2537' -0.15 -0.1010 +0.11 -0.0666 
SA84         16h16.7m +1440' -0.13 -0.1054 +0.37 -0.0546 
SA132        16h18.7m -1508' -0.33 -0.1165 -0.01 -0.0496 
V699_OPH     16h25.3m -0439' -0.38 -0.0666 +0.07 -0.0153 
CVN1682      16h25.9m +1546' -0.02 -0.1167 -0.05 -0.0376 
CVN1672      16h30.6m +1822' -0.07 -0.1068 -0.26 -0.0080 
PG1633       16h35.5m +0946' -0.26 -0.0925 -0.38 +0.0029 
CVN1061      16h43.3m +2649' -0.62 -0.0502 -0.23 -0.0573 
V651_HER     16h45.0m +0848' -0.09 -0.1473 +0.00 -0.0944 
GRB991208    16h45.1m +0848' -0.09 -0.1473 +0.00 -0.0944 
GSC0983      16h52.6m +1249' -0.05 -0.1016 -0.08 -0.0613 
GRB0508B     16h54.4m -2026' +0.15 -0.1638 +0.34 -0.0609 
G1534        17h03.1m +2139' -0.30 -0.0725 +0.05 -0.0674 
CVN1148      17h13.1m +3559' +0.07 -0.1115 -0.17 -0.0485 
GRB000926    17h17.1m +4308' -0.29 -0.1323 +0.04 -0.0918 
M92          17h17.2m +4308' -0.27 -0.1497 +0.04 -0.0965 
DL_HER       17h20.5m +1429' -0.92 -0.0142 -0.22 +0.0098 
G2605        17h26.0m +3048' -0.28 -0.0571 -0.10 -0.0644 
G1550        17h28.3m +2115' -0.33 -0.0724 -0.03 -0.0510 
NOPH98       17h32.1m -1914' +0.18 -0.1945 +0.42 -0.0768 
G2084        17h41.2m +2736' -0.66 -0.0243 -0.04 -0.0344 
ALS2         17h50.9m -1747' +0.34 -0.1756 +0.24 +0.0296 
NSGR01       17h54.7m -2614' -0.07 +0.0529 +0.19 +0.0569 
SN1999BS     18h01.8m +0701' +0.03 -0.1295  0.00 -0.0810 
J1859        18h01.8m +0702' +0.02 -0.1286  0.00 -0.0805 
MACHO18      18h02.0m -2723' +1.22 -0.1960 +1.65 -0.4587 
V4740_SGR    18h11.7m -3030' +1.42 -0.0950 +1.13 -0.0797 
G2622        18h12.2m +3056' -0.03 -0.1261 -0.42 +0.0282 
V343_SER     18h12.4m -1141' -0.26 -0.0946 +0.02 -0.0045 
V2756_SGR    18h14.6m -2949' +1.78 -0.0979 +1.34 -0.1961 
FG_SER       18h15.1m -0021' -0.27 -0.1089 +0.23 -0.0928 
GM_SGR       18h19.4m -2523' +2.27 -0.2355 +1.61 -0.2261 
G3116        18h21.1m +4439' +0.03 -0.1608 +0.38 -0.0759 
NSGR98       18h21.7m -2732' +0.80 -0.0521 +1.52 -0.3331 
V443_HERA    18h22.2m +2332' +0.16 -0.1245 -0.07 -0.0809 
CVN1437      18h22.7m +3258' -0.10 -0.1122 -0.37 +0.0827 
CVN1508      18h28.2m +2518' -0.04 -0.2155 +0.12 -0.0925 
V443_LYR     18h29.5m +3359' -0.36 -0.0458 +0.05 +0.0193 
J1859        18h29.5m +3400' -0.38 -0.0391 +0.03 +0.0258 
V531_LYR     18h32.5m +3626' -0.22 -0.0750 +0.03 +0.0211 
G3113        18h39.2m +4158' +0.24 -0.1197 +0.10 -0.0545 
K3_9         18h40.3m -0844' -0.62 +0.0136 +0.36 -0.0301 
V348_SGR     18h40.3m -2253' -0.28 -0.0146 +0.29 -0.0805 
CVN1573      18h41.3m +2844' +0.02 -0.1226 +0.14 -0.0478 
RZ_LYR       18h43.6m +3248' -0.41 -0.0829 -0.13 -0.0170 
CVN1641      18h43.7m +3249' -0.32 -0.1222 -0.13 -0.0281 
MWC960       18h48.0m -2006' -0.58 +0.0128 +0.34 -0.0700 
AS323        18h48.6m -0639' -0.53 +0.0966 +0.65 +0.1102 
NSGR94       18h50.6m -2123' -0.71 +0.0078 +0.31 -0.0698 
CI_AQL       18h52.0m -0128' -0.07 -0.0767 +0.02 -0.0145 
M57          18h53.5m +3302' -0.44 -0.0620 +0.02 -0.0112 
FN_SGR       18h53.6m -1903' -0.54 +0.0294 +0.45 -0.1218 
GSC3123      18h55.6m +4101' +0.13 -0.1334 -0.01 -0.0421 
V446_HER     18h57.4m +1315' +0.05 -0.1249 +0.49 -0.0978 
J1859        18h58.7m +2239' -0.41 +0.0004 +0.04 -0.0215 
NGC6738      19h01.4m +1138' +0.15 -0.1130 +0.03 -0.1395 
CM_AQL       19h03.5m -0300' -0.72 +0.0387 -0.21 +0.0637 
V1413_AQL    19h03.5m +1628' -0.38 -0.0283 +0.06 -0.0577 
V919_SGR     19h03.8m -1657' -0.22 -0.0932 -0.36 -0.0009 
NAQL01       19h07.5m +1145' +0.19 -0.1328 +0.02 +0.0002 
NAQL99       19h07.6m +1231' +0.06 -0.1028 +0.49 -0.0963 
V1089_SGR    19h08.8m -1721' -0.43 -0.0363 -0.03 -0.0034 
AP3_1        19h10.6m +0251' -0.64 +0.0438 +0.11 +0.0331 
CVN0487      19h15.5m +4453' -0.79 +0.0304 -0.06 +0.1324 
ALS_1        19h16.2m -0815' -0.24 -0.0714 -0.08 -0.0154 
V1494_AQL    19h23.1m +0458' -0.05 -0.0725 +0.03 -0.0299 
V335_VUL     19h23.2m +2432' -0.30 -0.0249 +0.28 -0.0758 
FY_AQL       19h28.1m +0343' -0.80 +0.0618 -0.16 +0.0204 
GRB010412    19h39.6m +1337' +0.46 -0.1194 +0.32 -0.0568 
QW_SGE       19h45.8m +1836' +0.02 -0.0943 +0.49 -0.0905 
M27          19h59.6m +2243' +0.07 -0.0812 +0.17 -0.0401 
NCYG01       20h07.3m +3605' +0.06 -0.1103 +0.30 -0.0834 
WZ_SGE       20h07.8m +1741' -0.47 -0.0591 -0.17 -0.0010 
J2009        20h09.8m +1558' -0.71 +0.0130 -0.21 -0.0024 
V1412_AQL    20h13.9m +0643' +0.01 -0.1188 +0.12 -0.0702 
PU_VUL       20h21.2m +2134' -1.06 +0.0842 -0.24 +0.0703 
V404_CYG     20h24.2m +3352' -0.19 -0.0433 +0.17 -0.0111 
BP_VUL       20h25.6m +2105' -0.24 -0.1143 -0.05 -0.0272 
NEPTUNE16    20h33.0m -1840' +0.04 -0.1492 -0.02 +0.0235 
NEPTUNE17    20h33.0m -1841' +0.04 -0.1493 -0.02 +0.0236 
NEPTUNE16    20h33.8m -1838' -0.01 -0.1289  0.00 +0.0308 
NEPTUNE15    20h34.6m -1834' +0.12 -0.1408 +0.04 +0.0078 
NEPTUNE14    20h35.4m -1831' +0.17 -0.1290 +0.02 +0.0200 
LT_DEL       20h35.9m +2009' -0.03 -0.1246 +0.10 -0.0377 
NEPTUNE13    20h36.1m -1829' +0.09 -0.1052 +0.01 +0.0165 
NEPTUNE12    20h36.8m -1826' +0.31 -0.1727 +0.09 -0.0069 
NEPTUNE11    20h37.5m -1823' +0.15 -0.1175 +0.07 +0.0366 
NEPTUNE01    20h38.3m -1820' +0.30 -0.1601 +0.08 +0.0232 
NEPTUNE10    20h38.3m -1821' +0.27 -0.1501 +0.06 +0.0265 
NEPTUNE9     20h39.1m -1818' -0.02 -0.1334 +0.18 -0.0040 
NEPTUNE8     20h39.8m -1815' +0.16 -0.1520 -0.09 +0.0145 
NEPTUNE7     20h40.6m -1812' +0.28 -0.1778 -0.11 +0.0469 
HEN2         20h41.1m +3446' -0.51 -0.0173 +0.05 -0.0322 
NEPTUNE6     20h41.3m -1809' +0.17 -0.1518 +0.07 -0.0011 
NEPTUNE5     20h42.0m -1807' +0.20 -0.1398 +0.04 +0.0196 
NEPTUNE2     20h44.0m -1758' +0.16 -0.1479 -0.07 +0.0239 
NEPTUNE01    20h44.7m -1755' -0.05 -0.0799 -0.06 +0.0242 
V523_CYG     21h02.0m +3518' -0.07 -0.1244 +0.06 -0.0591 
SS_CYG       21h42.8m +4336' -0.27 -0.0907 +0.27 -0.0910 
CY_AQR       22h37.9m +0133' +0.13 -0.1376 +0.05 -0.0835 
GRB991217    23h03.3m +0015' -0.23 -0.1008 +0.40 -0.1348 
GRB0519      23h04.6m +0110' -0.45 -0.0709 +0.08 -0.1253 
PG2337       23h40.1m +3019' +0.05 -0.1340 +0.25 -0.0689 
AT_AND       23h42.4m +4302' +0.09 -0.1417 +0.30 -0.0637 

Fig 1. Fields List

Fig 2. Fields (RA, DC)
Red = DC

Fig 3. B Offset for Magnitude 14.0 f(DC)
Red = Offset in 'B' for magnitude 14.0
Yellow = ax+b
Y Ticks = 0.1 magnitude
Points near Galaxy Center were discarded from the Fit.
Errors range from -1.060 to +0.460
Means Value is -0.171

Fig 4. R Offset for Magnitude 14.0 f(DC)
Red = Offset in 'R' for magnitude 14.0
Yellow = Best Fit
Y Ticks = 0.1 magnitude
Points near Galaxy Center were discarded from the Fit.
Errors range from -0.700 to +0.650
Means Value is +0.036

Fig 5. B Slope f(DC)
Red = Slope in 'B'
Yellow = Best Fit
Y Ticks = 0.1 magnitude
There is no significant dependance.
Means Value is -0.094

Fig 6. R Slope f(DC)
Red = Slope in 'R'
Yellow = Best Fit
Y Ticks = 0.1 magnitude
There is no significant dependance.
Means Value is -0.039

For any comment, contact Jean-Claude PELLE