Throughout much of the Theyalan Belt, people recognize several major celestial gods:
First is of course Yelm, the Sun. The Sun travels across the Sky Dome each day, only to die and enter the Underworld. He is reborn each dawn. Yelm is the patron of the rulers of Peloria and the Pure Horse People, but others consider him distant and unreachable to common people.
Second is Yelmalio, the Lightfore. Yelmalio is that part of Yelm that did not die and remained to provide light in the Darkness. Yelmalio is much easier to approach than Yelm, and the god aided humans, elves, and others to survive the Greater Darkness.
Beyond Yelm and Yelmalio is Dayzatar the Pure, the god of the Sky itself. Dayzatar is a god for mystics, monks, and ascetics, and rarely is of much use to ordinary people. His daughter Ourania leads the Celestial Chorus and protects purity. These deities are of little importance to the Theyalans, although they are acknowledged.
Polestar leads the stars and defends the Sky and those mortals who call for his aid.
There are the planets – wandering celestial gods. Some are friendly – Lokarnos, aka the Wheel or the Mule, who aids Issaries, some are hostile, such as Tolat, aka Shargash, who fights with Orlanth and the Storm Gods, or Artia the Bat, who is cursed. Most are acknowledged but play little importance in stories, such as Moskalf or the Twin Stars.
Finally there is the Red Moon, whose presence fills many Theyalans with unease or even dread. She is acknowledged, although most Theyalans view her as a dangerous (but very powerful) interloper.
Some add Annilla to this, but outside of the coastal areas (where she is revered for being the Maker of Tides), she plays little roles in most stories.
Your ordinary Orlanth or Ernalda cultist would know all these deities.
Do Sun Domers venerate Dayzatar and Ourania? Even amongst the Sun Dome temples these cults are marginal. Their cults are very small and the deities are almost always worshiped as associates of another deity. You have to get into the Heartlands to find much of an independent cult for either.
Antirius? Antirius is simply another name for Yelmalio. Is this known by the Yelmalio and Pelorians? It is generally known that Dara Happan is a different language from the Theyalan languages and they have different names for things. But just as we know that both “kibtu” and “godhūma” are different words for wheat, we also know that they both refer to the same thing.