[KIDS] Vignetting at the connector-edges of CCDs

[Hugo Buddelmeijer]

Dear KiDS group,

The KiDS frames show vignetting at the edges that are close to the CCD 
connectors. Hereby a short summary of the effect that this vignetting 
has on our data. The wiki contains the details:
   http://wiki.astro-wise.org/projects:kids:tbarvignetting

The main conclusions:
* The effect of the vignetting can be separated into two regions:
   * The 'inner region', very affected:
     * The 50 pixels closest to the connector edge of the outer 16 CCDs.
     * An error in the photometry of about 1%-3% is typical.
     * It will probably be very difficult to correct this region.
   * The 'outer region', mildly affected:
     * The 400 pixels closest to the connector edge of all 32 CCDs.
     * An error in the photometry of <1% is typical.
     * It is probably feasible to improve the photometry in this region.

The best way to handle the vignetting will depend on the science goals. 
The inner region might be unsuitable for most science projects.

Greetings,
Hugo Buddelmeijer