Starship Asterisk*

The Phases of Venus

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.

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How long does it take for Venus to complete one orbit around the Sun?
smash karts

maryplouffe wrote: ↑Mon Jan 08, 2024 8:38 am How long does it take for Venus to complete one orbit around the Sun?

It takes 225 days.

You can learn more about Venus here.

Ann

Fun fact: a day on Venus lasts longer than a year on Venus!

maryplouffe wrote: ↑Mon Jan 08, 2024 8:38 am How long does it take for Venus to complete one orbit around the Sun?

As Ann notes, its (sidereal) orbital period is about 225 days. But perhaps more relevant to what we see (and what is illustrated in today's APOD) is the relationship between the orbits of Earth and Venus. That results in Venus having an apparent phase cycle of 584 days.

A truly full phase of Venus would be nearly impossible to see from Earth. The view from Mercury would be spectacular, of course. Has anyone seen a photo of the full phase of Venus by any of the few space probes that have ventured that far sunward?

EricOsman wrote: ↑Mon Jan 08, 2024 5:14 pm A truly full phase of Venus would be nearly impossible to see from Earth.

You could say the same thing about viewing the phases of the Moon from Earth!

I wonder if the 3d and 4th crescents are shown in the wrong order

I wonder about the sliver crescent image. I would think that would only be "up" during the day.

cmflyer wrote: ↑Mon Jan 08, 2024 8:55 pm I wonder about the sliver crescent image. I would think that would only be "up" during the day.

It is easy to image (and even see visually) Venus when the Sun is above the horizon.