Astronomy Picture Of The Day Calendar. Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Stargazers will be treated to a rare alignment of seven planets on 28 february when mercury joins six other planets that are already visible in the night sky.

Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Here’s why it matters to.