<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Robert,<div class=""><br class=""></div><div class="">Following your reference it takes the flux of a zero magnitude object (units: ADUs), <a href="http://lsst-web.ncsa.illinois.edu/doxygen/x_masterDoxyDoc/classlsst_1_1afw_1_1image_1_1_calib.html#a823f25da4fabd26b51a83855a4284d88" class="">REF</a>. You can see an example of setting it <a href="http://lsst-web.ncsa.illinois.edu/doxygen/x_masterDoxyDoc/scale_zero_point_8py_source.html#l00139" class="">here</a>.<div class=""><br class=""></div><div class="">Thank you,</div><div class="">Will</div><div class=""><br class=""><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 27, 2015, at 4:53 PM, Russell Owen <<a href="mailto:rowen@uw.edu" class="">rowen@uw.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=windows-1252" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">The C++ source code or Doxygen documentation is the place to look for documentation on wrapped C++ code. Unfortunately. We’re planning to fix that at some point. Meanwhile:<div class=""><br class=""></div><div class=""><a href="http://lsst-web.ncsa.illinois.edu/doxygen/x_masterDoxyDoc/search.php?query=Calib" class="">http://lsst-web.ncsa.illinois.edu/doxygen/x_masterDoxyDoc/search.php?query=Calib</a></div><div class=""><br class=""></div><div class="">returns the information you need. The first link goes to the Calib class which has two overloaded versions of setFluxMag0, the first of which certainly looks relevant (I’m not sure if the second has been exposed in Python).</div><div class=""><br class=""></div><div class="">— Russell<br class=""><div class=""><div class=""><br class=""><div class=""><div class="">On May 27, 2015, at 4:32 PM, Will Dawson <<a href="mailto:will@dawsonresearch.com" class="">will@dawsonresearch.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite" class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Jim et al.,<br class=""><div class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On May 26, 2015, at 9:06 AM, Jim Bosch <<a href="mailto:jbosch@astro.princeton.edu" class="">jbosch@astro.princeton.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">In this case, "Calib" object refers to "afw.image.Calib", which is the object we attach to an Exposure to store its magnitude zeropoint (and other photometric calibration information). CModel needs it (as well as a Wcs) because it works in absolute units so it can use Bayesian priors (though it just uses flat priors by default). So if you can construct a afw.image.Calib object, give it a reasonable zeropoint, and add it to the Exposure (with exposure.setCalib(...)), that should solve your problem.</span></div></blockquote></div><br class=""></div><div class="">Follow up question regarding setting the zero point with lsst.afw.image.Calib. I see a function called lsst.afw.image.Calib.setFluxMag0() but it isn’t clear from the title of this function what input I should give it, and the doc string returns:</div><div class=""><br class=""></div><div class=""><pre style="box-sizing: border-box; overflow: auto; font-size: 14px; padding: 0px; margin-top: 0px; margin-bottom: 0px; line-height: 17.000059127807617px; word-break: break-all; word-wrap: break-word; border: 0px; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; white-space: pre-wrap; vertical-align: baseline;" class="">Help on method setFluxMag0 in module lsst.afw.image.imageLib:
setFluxMag0(self, *args) unbound lsst.afw.image.imageLib.Calib method
setFluxMag0(Calib self, double fluxMag0, double fluxMag0Sigma=0.0)
setFluxMag0(Calib self, double fluxMag0)
setFluxMag0(Calib self, pairDoubleDouble fluxMag0AndSigma)</pre><div class=""><br class=""></div></div><div class="">So I am left wondering if I should input:</div><div class="">— zero point magnitude (e.g. 31) or,</div><div class="">— flux for a zeroth mag object (e.g. 4760 Jy; Schneider, Gunn, & Hoessel (1983)). If so what units and I guess I should specify other telescope specific properties. Or,</div><div class="">— something else?</div><div class=""><br class=""></div><div class="">For coding simplicity I am guessing it is just the zero point magnitude, but the function name is making me nervous about simply assuming that.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">Will</div></div>_______________________________________________<br class="">dm-users mailing list<br class=""><a href="mailto:dm-users@lists.lsst.org" class="">dm-users@lists.lsst.org</a><br class=""><a href="https://lists.lsst.org/mailman/listinfo/dm-users" class="">https://lists.lsst.org/mailman/listinfo/dm-users</a></blockquote></div><br class=""></div></div></div></div></div></blockquote></div><br class=""></div></div></div></body></html>