The Olympus Sect

To be fair, worshiping the celestial bodies of our solar system isn't even half as crazy as some of the cults out there.
The Olympus Sect is perhaps the most popular religion in the modern era, practiced by many people across Earth and the solar system. To a varying degree, at least. It's more popular in some places than in others. As a general rule, the farther you get from the sun, the less popular it'll be found.
Adherents to the religion treat the planets of the solar system, as well as their moons and the other celestial bodies of the solar system, as gods. Or, more accurately, as the embodiments of the gods they're named after. The planets are representative of their namesakes. Poseidon is the patron of salors of both seas, naval and stellar.
It's not an highly involved religion, for the most part. Rituals and prayers are largely left up to the individual, and families usually have their own traditions they follow that differ from one to the next. One family might leave food on an alter dedicated to the god they seek their blessing from, while another might drink to their name and believe their libations are going to the god as they celebrate. 
There is some common elements. The domains of each god are relatively static, though their disposition can change from person to person. Accepted behavior towards the gods, while a broad umbrella, is also relatively standard among adherents. Holidays are perhaps the most static, along with their respective meanings and celebration, meaning that some days a year jubilant celebration or somber remembrance can be taking place at the same time in every corner of the solar system.

Cosmological Views

The Olympus Sect isn't a religion that has it's own creation myth, it isn't as in-depth as that. 
The gods of the Sect are more along the lines of patron saints in the sense that they are believed to watch over and aid the faithful, but not that they created the universe or the planets bearing their names. They're believed to be powerful, but the creation of the universe is simply not part of the discussion. Those that worship are far more concerned with the now, rather than the before.

May the Planets Align for all your Endeavors

Founding Date

Unknown, but at least 200 years ago.

Type

Religious, Cult

Alternative Names

Planet-Watchers