in Fig. \[uitcmd\] are available upon request to the authors.

Although the UIT colour-magnitude diagram is of poorer quality than that shown in Brown et al. ([@brsw01]), it is still possible to identify the candidate sub-ZAHB stars. Unfortunately, all but one of our blue hook targets are less than 0.3 mag fainter than the hottest canonical ZAHB model at m$_{1520}$ = 16.72. Only W20334 at m$_{1520}$ = 17.35 is near the faint end of the blue hook distribution found by Brown et al. (2001). Thus our choice of targets is biased toward the brighter blue hook stars.

Spectroscopy
------------

We obtained medium-resolution spectra ($R\approx$900) of 19 stars along the blue tail in NGC 2808 with $< V <$ at the VLT-UT1 (Antu) with FORS1 see Fig. \[cmd\]). The data were obtained in service mode (see Table \[tab-obs\] for details). We used the multi-object spectroscopy (MOS) mode of FORS1 (slit length 19) with the standard collimator (02/pixel), a slit width of 1 and grism B600. As FORS1 is equipped with an atmospheric dispersion corrector, MOS observations at higher airmass are not a problem. The detector was a TK2048EB4-1 backside thinned CCD with 2048$\times$2048 pixels of (24 $\mu$m)$^2$, which was read out 