f Meeting date 04.-06.02.2003 ref./rИf. ... This can be done in energy-channel conversion in PEM. detector noise in eFF · Vela SNR: FWHM of eFF observation tends to be somewhat smaller 3.3 Konra d De nne rl ­ O pt ical loa di ng · Optical PSF larger than X-ray PSF · Optical loading and counting mode : ° star of mag 6 is sufficient in FF mode with the thin filter to trigger counting mode by optical loading, if a flat offset map is used ° counting ...