High-resolution imaging of Virgo cluster galaxies – I. Observational techniques and first results

We investigate the potential of the image sharpening technique for making high-resolution images of Virgo cluster galaxies, in order to obtain new estimates of this cluster's distance. We have used both the Galway Image Sharpening Camera (Redfern et al.) and the MARTINI instrument (Doel et al.) at the William Herschel Telescope to confirm Fried's almost-equal-to 4r0 optimum aperture for image sharpening. We have further used the MARTINI image sharpening instrument to observe the Virgo galaxy, IC3583. The resulting image has 0.60-arcsec FWHM seeing but to a limiting magnitude of R = 21.7 mag the brightest stars in IC3583 are not resolved. This tentatively suggests a lower limit to the Virgo distance modulus of m - M > 30.7 mag.