It is true, however, that the difference is observable in page-size photographs that lie side by side on a table. There is an old project physics activity that has the student plot the distance to the sun based on changes in the apparent size of the sun; and from this data you can computer the shape of the earth's elliptical orbit to some degree of accuracy. You can also get the perihelion and aphelion distances and dates from this sort of data.
Jeff Adkins "Richard M. Koolish" wrote: > >From the web page: > >http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/SEgeometry.html > > "Eclipse geometry is complicated by the fact that Earth's orbit around the Sun > is elliptical. As a result, the Sun's apparent semi-diameter varies from 944 > arc-seconds at aphelion to 976 arc-seconds at perihelion. This 3% range in > apparent size is, of course, quite indistinguishable to the naked eye." Content-Type: text/x-vcard; charset=us-ascii; name="Astronomer.vcf" Content-Transfer-Encoding: 7bit Content-Description: Card for Jeff Adkins Content-Disposition: attachment; filename="Astronomer.vcf" Attachment converted: Macintosh HD:Astronomer.vcf 1 (TEXT/ttxt) (00020FD9)
