- R. Cutri:
reported that he has received data from
the SLOAN survey in the SA57 region for a detailed comparison with
2MASS data.
- T. Evans:
showed some results from her analysis
of the magnitude difference between R2 and R2-R1 photometry for stars
in the FS calibration data. She is checking the distribution of delta
mag. as a function of seeing (pfrac) in order to determine whether a
single magnitude calibration per scan between R2-R1 and R2 will be
sufficient. She finds no trends in delta mag. with pfrac, so this
supports the plan to obtain a single R2-R1 photometric calibration to
the R2 scale per scan. Next she will examine some survey scans as a
further check.
- S. Terebey:
presented her modelling of the FWHM of
the PSF as a function of seeing; see her already released memo on the
subject for more details. The bottom line is that the 2D Moffatt
function seeing model convolved with the 2MASS pixel response, taking
into account the random star-pixel offsets, is approximated well by a
simple analytical rms convolution: FWHM(frame)^2 = FWHM(seeing)^2 +
2arcsec^2. The Frame FWHM does not drop below 2 arcseconds.