From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Sat Nov 02 2002 - 14:50:27 PST
I have performed a calculation in the spirit of Alex Conley's note
about how the range of seeing in last night's Subaru data effects the
PSF, and thus the relative depth. For each SXDF field, I have collected
all the seeing measurements from Naoki, and their corrresponding
exposure times. I then created an exposure-scaled Gaussian PSF for each
frame and added the Gaussians frame by frame in order from best to
worst seeing. After adding each new frame, I fit a new Gaussian and
take its FWHM as the measure of the effective seeing in the sum. The
result is the effective seeing of the coadd as a function of
seeing-sorted image number for each field. I then calculated the
effective depth relative to a fiducial having the same total exposure
time, but seeing FWHM of 0.8", so one can see how the effective depth
grows as images with worse seeing are added. I also calculated the
value of that effective depth relative to a fiducial 50 minute exposure
with 0.8" seeing.
The summary is that if we coadd everything, the effective depths relative
to 50 minute exposure with 0.8" seeing are 0.75, 0.79, 0.82, 0.71 and
0.92 in fields 1-5, respectively. If we only sum images with FWHM < 0.9"
then the relative effective depths are 0.61, 0.69, 0.64, 0.47 and
0.75, respectively.
Here are the full results. Note that for frames where Naoki didn't
measure the exposure I assumed the seeing was the equal to the worst
within the sequence in which it was measured. This is a mildly
conservative an assumption. If anyone wants to rerun/hack the code, it
is in /home/astro10/aldering/idl and called sxdf.pro; it reads
sxdf.seeing2 to get the data.
Field Frame Seeing Exptime FWHM of Relative Relative
FWHM Summed PSF Exptime Depth
------------------------------------------------------------
SXDF_1 1 0.70 180 0.700000 235 0.078367
SXDF_1 2 0.75 180 0.724898 438 0.146153
SXDF_1 3 0.75 180 0.733254 642 0.214261
SXDF_1 4 0.80 180 0.749798 819 0.273214
SXDF_1 5 0.81 240 0.764763 1050 0.350168
SXDF_1 6 0.82 240 0.775761 1276 0.425387
SXDF_1 7 0.85 180 0.785355 1431 0.477316
SXDF_1 8 0.85 240 0.794877 1640 0.546983
SXDF_1 9 0.87 240 0.804494 1839 0.613093
SXDF_1 10 0.97 240 0.822788 1985 0.661763
SXDF_1 11 1.05 180 0.839782 2069 0.689700
SXDF_1 12 1.20 180 0.863489 2111 0.703850
SXDF_1 13 1.20 180 0.884693 2158 0.719578
SXDF_1 14 1.20 180 0.903697 2209 0.736652
SXDF_1 15 1.20 180 0.920777 2264 0.754869
------------------------------------------------------------
SXDF_2 1 0.75 180 0.750000 204 0.068266
SXDF_2 2 0.75 180 0.750000 409 0.136533
SXDF_2 3 0.75 180 0.750000 614 0.204800
SXDF_2 4 0.75 180 0.750000 819 0.273067
SXDF_2 5 0.78 240 0.757469 1070 0.356944
SXDF_2 6 0.78 180 0.761016 1259 0.419929
SXDF_2 7 0.83 240 0.772876 1478 0.492855
SXDF_2 8 0.85 240 0.784161 1686 0.562036
SXDF_2 9 0.85 240 0.792585 1894 0.631656
SXDF_2 10 0.90 240 0.804634 2075 0.691961
SXDF_2 11 1.06 180 0.823382 2152 0.717448
SXDF_2 12 1.16 180 0.845677 2201 0.733812
SXDF_2 13 1.16 180 0.865577 2255 0.751712
SXDF_2 14 1.16 180 0.883378 2312 0.770929
SXDF_2 15 1.20 180 0.901335 2363 0.787784
------------------------------------------------------------
SXDF_3 1 0.67 180 0.670000 256 0.085542
SXDF_3 2 0.71 180 0.689936 484 0.161340
SXDF_3 3 0.75 180 0.709830 685 0.228636
SXDF_3 4 0.76 180 0.722322 883 0.294395
SXDF_3 5 0.78 180 0.733792 1069 0.356578
SXDF_3 6 0.80 240 0.747643 1305 0.435086
SXDF_3 7 0.83 240 0.761832 1521 0.507247
SXDF_3 8 0.84 240 0.773329 1733 0.577890
SXDF_3 9 0.87 240 0.785665 1928 0.642832
SXDF_3 10 0.92 240 0.800700 2096 0.698777
SXDF_3 11 1.05 120 0.813295 2148 0.716005
SXDF_3 12 1.07 180 0.831429 2221 0.740661
SXDF_3 13 1.20 120 0.847156 2247 0.749087
SXDF_3 14 1.25 120 0.863460 2266 0.755402
SXDF_3 15 1.25 180 0.886025 2298 0.766329
SXDF_3 16 1.25 120 0.899900 2323 0.774493
SXDF_3 17 1.25 120 0.912916 2349 0.783283
SXDF_3 18 1.30 180 0.933141 2381 0.793797
SXDF_3 19 1.30 180 0.951666 2416 0.805592
SXDF_3 20 1.30 180 0.968650 2455 0.818516
------------------------------------------------------------
SXDF_4 1 0.68 180 0.680000 249 0.083045
SXDF_4 2 0.72 180 0.699936 470 0.156764
SXDF_4 3 0.75 180 0.716540 673 0.224374
SXDF_4 4 0.77 180 0.729832 865 0.288367
SXDF_4 5 0.82 180 0.747638 1030 0.343493
SXDF_4 6 0.88 240 0.774970 1214 0.404943
SXDF_4 7 0.89 240 0.794769 1398 0.466076
SXDF_4 8 0.94 240 0.815923 1557 0.519129
SXDF_4 9 0.95 240 0.833049 1715 0.571782
SXDF_4 10 0.97 240 0.848550 1866 0.622191
SXDF_4 11 1.05 180 0.863962 1954 0.651635
SXDF_4 12 1.20 180 0.886570 2003 0.667679
SXDF_4 13 1.22 180 0.907760 2050 0.683472
SXDF_4 14 1.23 180 0.927230 2099 0.699734
SXDF_4 15 1.33 180 0.949447 2129 0.709967
------------------------------------------------------------
SXDF_5 1 0.70 240 0.700000 313 0.104490
SXDF_5 2 0.71 180 0.704282 541 0.180641
SXDF_5 3 0.72 240 0.709988 837 0.279319
SXDF_5 4 0.74 180 0.716393 1047 0.349169
SXDF_5 5 0.75 180 0.722296 1251 0.417089
SXDF_5 6 0.75 180 0.726438 1455 0.485113
SXDF_5 7 0.78 240 0.735294 1704 0.568198
SXDF_5 8 0.82 240 0.747219 1925 0.641907
SXDF_5 9 0.83 180 0.755128 2087 0.695873
SXDF_5 10 0.90 240 0.771199 2259 0.753260
SXDF_5 11 1.00 120 0.782810 2318 0.772857
SXDF_5 12 1.05 180 0.801489 2391 0.797031
SXDF_5 13 1.10 180 0.820830 2450 0.816905
SXDF_5 14 1.10 120 0.832545 2493 0.831011
SXDF_5 15 1.13 120 0.844468 2530 0.843610
SXDF_5 16 1.13 120 0.855578 2570 0.856816
SXDF_5 17 1.13 120 0.865947 2611 0.870557
SXDF_5 18 1.15 180 0.881186 2670 0.890160
SXDF_5 19 1.20 180 0.897230 2718 0.906312
SXDF_5 20 1.20 180 0.911913 2770 0.923537
This archive was generated by hypermail 2.1.4 : Sat Nov 02 2002 - 14:50:48 PST