The airy disk is the small disk that appears at focus for a star surrounded by diffraction rings. The larger the aperture the smaller the disk hence large apertures have more resolving power. If the telescope is large enough (and out of our atmosphere) the airy disk could be smaller than the star and you could then resolve details on a distant star. The same thing can be done through long baseline interferometry by using optics some distance apart and making an effective aperture the distance between the two optics. This is how they have resolved detail on some bright stars. Unfortunately the interferometry method does not provide you with light gathering power and would be useless for such a project unless the light gathering ability of the optics was sufficient to see a planet. Clear Skies Don -----Original Message----- From: utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com [mailto:utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Thursday, April 13, 2006 5:11 PM To: Utah Astronomy Subject: RE: [Utah-astronomy] Can't quite figure this one Thanks, Kurt and Michael. The "airy disk" doesn't involve light scattering, but the telescope's optics -- is that right? I am starting to understand it a little better. Best wishes, Joe _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.utahastronomy.com