From: Vitaliy Fadeyev (VAFadeyev@lbl.gov)
Date: Sat Apr 03 2004 - 16:52:53 PST
Rob,
Natalia, Lifan and I are going to do this now.
vitaliy
"Robert A. Knop Jr." wrote:
> At some point (probably not until late late tonight) Subaru I-band
> subtractions will start showing up.
>
> These are the zeropoints that will be used for them:
>
> sub04mar/mar172004suprimea28956sum.fts | 38.1048017998
> sub04mar/mar172004suprimeb28956sum.fts | 38.1206147516
> sub04mar/mar172004suprimec28956sum.fts | 37.131587848
> sub04mar/mar172004suprimed28956sum.fts | 36.8684151492
> sub04mar/mar172004suprimef28956sum.fts | 37.7517776011
> sub04mar/mar172004suprimee28956sum.fts | 37.5677277862
> sub04mar/mar172004suprimeg28956sum.fts | 37.3110273633
> sub04mar/mar172004suprimeh28956sum.fts | 37.2026060372
> sub04mar/mar172004suprimei28956sum.fts | 37.5857562505
> sub04mar/mar172004suprimej28956sum.fts | 36.4820993053
> ^
> |
>
> The indicated letter is the chip of the subtraction.
>
> These zeropoints are completely bogus. (They are based on the R
> magnitudes from the USNO catalog and should not be trusted to better
> than a magnitude or two.) I need somebody to figure out a reasonable
> zeropoint for these images. At that point, we will need to adjust any
> magnitudes that come off of the Subaru subtractions by the *difference*
> between this zeropoint and the real zeropoint determined for these
> images.
>
> These are I-band images. You can get at them with
>
> finddbfile -g <filename>
>
> or
>
> imview -scp <filename>
>
> Note that the night was decidedly not photometric, so just taking a
> published Suprime-Cam zeropoint won't work. (Plus, I'm not sure about
> the units of this sum.) We have to do something empirical to get a
> vega-based zeropoint for these imgaes. Perhaps match and compare to
> GODOS images (whose zeropoints *should* be good), or perhaps match and
> compare to pre-existing calibrated data.
>
> This will be a painful hand-work task, and I don't have time to do it.
>
> The same may eventually need to be done for the subaru z-band images.
>
> -Rob
>
> --
> --Prof. Robert Knop
> Department of Physics & Astronomy, Vanderbilt University
> robert.a.knop@vanderbilt.edu
This archive was generated by hypermail 2.1.4 : Sat Apr 03 2004 - 16:53:15 PST