Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2024 January 8
Many images of Venus are shown superposed. Together, they
make an arc from the top, around the left, to the bottom. The 
smallest images of Venus are at the top and show nearly complete
circles. The largest are at the bottom and show thin crescent.
phases. 
Please see the explanation for more detailed information.

The Phases of Venus
Image Credit & License: Stéphane Gonzales

Explanation: Venus goes through phases. Just like our Moon, Venus can appear as a full circular disk, a thin crescent, or anything in between. Venus, frequently the brightest object in the post-sunset or pre-sunrise sky, appears so small, however, that it usually requires binoculars or a small telescope to clearly see its current phase. The featured time-lapse sequence was taken over the course of six months in 2015 from Surgères, Charente-Maritime, France, and shows not only how Venus changes phase, but changes angular size as well. When Venus is on the far side of the Sun from the Earth, it appears angularly smallest and nearest to full phase, while when Venus and Earth are on the same side of the Sun, Venus appears larger, but as a crescent. This month Venus rises before dawn in waxing gibbous phases.

Free APOD Lecture: January 9, 2024 to the Amateur Astronomers of Association of New York
Tomorrow's picture: Thor's hat


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