I don't know all of the answer to this, but I believe that part of the issue is scattering due to the diffraction that is inherent in any optical system. Hence (I think) it is impossible to create an image of a point source that is also a point. Of course, the pixel size of the receptor also makes a difference. For all you optical geniuses, what else am I missing? Kim -----Original Message----- From: utah-astronomy-bounces+kimharch=cut.net@mailman.xmission.com [mailto:utah-astronomy-bounces+kimharch=cut.net@mailman.xmission.com] On Behalf Of Joe Bauman Sent: Thursday, April 13, 2006 11:03 AM To: Utah Astronomy Subject: [Utah-astronomy] Can't quite figure this one I have an optics question. A recent article mentioned how hard it would be to detect the tiny speck of light emitted by an exoplanet, because of the overwhelming brightness of the parent star. Fair enough. However, if a telescope in space were to use a tiny device to block the star's light, you'd think that would allow a view of the planet. -- I'm sure that's not right. But why isn't it? In space, isn't a star basically a point source? I would exepct no light scattering in what is essentially a vacuum. So what's wrong with that idea? Thanks, 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 ______________________________________________________________________ This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net ______________________________________________________________________