Astronomy Picture of the Day . ... The Sun setting through Earth's atmosphere. ... In the above image from the ASTER camera.. ... Called a solstice, the date traditionally marks a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere. ... Seen here on June 13th from southern New Mexico, this Comet McNaught's long ion tail sweeps across the telescopic field of view (a negative image is inset). APOD is 15 Years Old Today . ...