This is the directory of selected pictures for Portal:Astronomy. For the old (no longer functional) version of this page, see Portal:Astronomy/Picture/Old.
- Use the template above. Fill out the Image, Text, Credit, and Link fields. You do not need to fill out the other two.
- All selections must be a Featured Picture on English Wikipedia or Wikimedia Commons.
- Use images that are roughly square shaped. If an image is too wide, it will wind up outside of its section on the Portal mainpage. If it is too tall, it will unbalance the columns.
- When adding new items, remember to update the max= field on the Portal:Astronomy page.
Sunspots are temporary phenomena on the surface of the Sun (the photosphere) that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection, forming areas of reduced surface temperature. Although they are at temperatures of roughly 3,000–4,500 K (4,940–7,640 °F), the contrast with the surrounding material at about 5,780 K leaves them clearly visible as dark spots, as the intensity of a heated black body (closely approximated by the photosphere) is a function of T (temperature) to the fourth power.
Cassiopeia A (Cas A) is a supernova remnant in the constellation Cassiopeia and the brightest astronomical radio source in the sky, with a flux of 2720 Jy at 1 GHz. The supernova occurred approximately 11,000 light-years (3.4 kpc) away in the Milky Way.