Here's why:
* Earth's Orbit: As the Earth revolves around the Sun, our perspective of the night sky changes. This is similar to how the scenery outside your car window appears different as you drive.
* Seasonal Visibility: In October, the Earth is positioned in its orbit so that Leo, which is a constellation visible in the Northern Hemisphere during the spring and summer months, is now positioned on the opposite side of the Sun from us.
* Sun's Position: The Sun's position in the sky changes throughout the year, and in October, the Sun is in the same part of the sky as Leo. This means the Sun's light washes out Leo's stars, making it invisible.
In summary: The Earth's revolution around the Sun causes a change in our perspective, making certain constellations visible at certain times of the year and not others.
