I had a question about the defocus slider in the web interface. We are trying to get photometric data of a magnitude 5-6 star from Namibia. Using maximum defocus (30000) we are still saturating on the star with both the iDK (ID 6686) and Veloce (ID 6732), likely even if we were to take the minimal exposure time and 1x1 binning (at the moment we tested it with 5s integration 1x1 binning for the iDK, and 2x2 binning for the Veloce). More defocus would allow us to be more efficient (less but longer integrations and binning, leading to better photometry and reduced overheads and less storage).
So ideally we would like to defocus beyond the 30000 limit, maybe as far to get small donut-like stars. Is it possible to extend the defocus range or is there any particular hardware limit or another general concern ?
If we use narrowband filters to get rid of the excess light the photometry will become sensitive to the spectral features in the stars so we would like to avoid that approach.
An alternative route might be that I put the target star on the edge of the Veloce field where the transmission is lower and the PSF might be a bit more elongated out of focus.
Another alternate route is that I enter fake orbital elements through the astrometry/photometry tab to smear out the light over a few pixels 😅 .