From: Greg Aldering (aldering@panisse.lbl.gov)
Date: Mon Apr 05 2004 - 18:58:36 PDT
I should add that these zeropoints to which Vitaliy referred are from the
zeropoints database on brahms.
- Greg
On Mon, 5 Apr 2004, Vitaliy Fadeyev wrote:
>
>
> Rob,
>
> according to Greg, it looks like the zeropoints in the Z-band news
> are all constant, and defined to be around 32.32, with a note
> that they are from the header.
>
> For candidate 76 field, I get the zeropoint (translated from GOODs
> AB zeropoint with -0.56 correction to the Vega, and relative aperture
> photometry) of 32.39 +- 0.10.
>
> vitaliy
>
>
>
> "Robert A. Knop Jr." wrote:
>
> > I've only tested one case, in Z-band, but what I found was that my
> > aperture correction was ~0.6 magnitudes *too big*. This would tend to
> > make our candidates 0.6 magnitudes *too bright*.
> >
> > As such, we can "fix" our Z-band magnitudes by *adding* 0.6mag to them.
> > I think this brings us nicely in line with what Adam et al. have.
> >
> > (The reason we were closer last week was that I was using a bigger-- too
> > big for efficiency purposes-- aperture, and with bigger apertures,
> > errors in aperture corrections aren't as noticable.)
> >
> > I still haven't exactly tracked down this aperture correction error in
> > the code, nor have I checked this in I-band, but this is what it looked
> > like was happening.
> >
> > I apologize for the horrendous screw-up.
> >
> > -Rob
> >
> > --
> > --Prof. Robert Knop
> > Department of Physics & Astronomy, Vanderbilt University
> > robert.a.knop@vanderbilt.edu
>
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