... Also known as the Seven Sisters and M45 , the Pleiades is one of the brightest and most easily visible open clusters on the sky. The Pleiades contains over 3,000 stars, is about 400 light years away, and only 13 light years across. Surrounding the stars is a spectacular blue reflection nebula made of fine dust. ... Also known as NGC 1499 , this mass of red glowing hydrogen gas is about 1,500 light years away. ... Publications with keywords: California Nebula - dust . ...