The planet Venus, long known as the morning or evening star, is one of the brightest objects in our skies and has inspired poets throughout history.
It is so bright that it can cast shadows and can even be seen (albeit rarely) with the naked eye in the middle of the day. This happened once in 1716 when Londoners were alarmed by it appearance in the daytime. I’ve seen it once at around 4 or 5 PM in the afternoon after carefully checking its location relative to the Sun and Moon.
I managed to capture Venus through my telescope this week, having observed it telescopically only once before.
Visual Observation
Venus is the second planet in the Solar System and has an orbit smaller than Earth’s. From our perspective, it always appears less than 47 degrees from the Sun. Hence, Venus makes its appearance before sunrise or after sunset, giving rise to its title of morning or evening star.
Venus has an extremely dense atmosphere comprising mostly of carbon dioxide. Even though Venus is Earth-sized, the atmospheric pressure at the surface is more than 90 times that of Earth’s! Its runaway greenhouse effect results in Venus having the highest surface temperature in the Solar System, even higher than Mercury, the planet closest to the Sun.
Thick clouds of sulfuric acid perpetually blanket Venus, preventing visual observation of the surface. These clouds reflect 90% of the incident sunlight back into space, contributing to its visual brightness. This also makes for somewhat boring observations. Ultraviolet or infrared observations may show more detail.
However, Venus displays phases like those of the Moon when viewed through a telescope. It appears small and as a full disc when it is on the opposite side of the Sun (superior conjunction). Venus shows a larger disc and a quarter phase shape at its maximum elongation from the Sun when it is brightest in the sky. The planet presents an even larger crescent shape as it passes near the Earth. However, due to it’s proximity to the Sun, it becomes difficult (and potentially dangerous) to observe.