The pictures on the home-page change with seasonal frequence. You can find them all collected here.
Autumnal equinox 2009
Vernal equinox 2010
Autumnal equinox 2010
Winter solstice 2010
Vernal equinox 2011
Summer solstice 2011
Autumnal equinox 2011
Winter solstice 2011
Vernal equinox 2012
Summer Solstice 2012
Winter solstice 2012
Vernal equinox 2013
Summer solstice 2013
Autumnal equinox 2013
Winter solstice 2013
Vernal equinox 2014
Autumnal equinox 2014
Summer solstice 2016
Winter solstice 2016
Winter solstice 2017
Autumnal equinox 2018
Vernal equinox 2019
Vernal equinox 2020
Vernal equinox 2021