astronut wrote:based on the chart of venus phase provided here whichis the bightest phase and how would you determine it
Venus is brightest when the largest "surface" of it is illuminated, as seen from the Earth
When Venus is "full", an entire hemisphere of it is bathing in sunlight, as seen from the Earth. Unfortunately that only happens when Venus is on the other side of the Sun from the Earth. When that happens, Venus looks quite small in our skies, and Venus is far from maximum brightness.
So when Venus is full, it is as far away from the Earth as it can be. At that point, Venus is said to be at opposition. After that, Venus approaches us. That is because its orbit is inside the Earth's orbit, and it moves faster than the Earth does.
As Venus approaches us, it first turns gibbous, then "half", then it becomes a crescent. But while only a smaller and smaller part of Venus becomes illuminated, as seen from the Earth, the illuminated part grows larger and larger.
Venus is, as I said, brightest when the illuminated part of it covers the maximum amount of "surface" in our skies. That happens when Venus is a crescent, but not when it is a tremendously thin crescent.
I believe Venus was at its brightest in early or mid February this year. Now, its crescent is growing thinner and thinner. Soon Venus will be "right in front of the Sun", it will show us its unilluminated side only, and we wouldn't be able to see it right in front of the Sun anyway.
In January, February and March, Venus has shown itself in the Earth's evening skies. When Venus returns to our skies after it has been invisible because it was unilluminated and was right in front of the Sun, it will be a morning object.