The egg catalog, pet catalog and radar guide measure different things. The checked sources publish no conversion formula among them.
Egg Luck is a catalog field
The egg table ranges from White Egg at 1 Luck to Cherub Egg at one trillion Luck. It describes the listed egg progression value, not the chance of hatching a specific pet.
Pet odds are separate claims
A pet table may list Fox as 1 in 21 million or Kitsune as 1 in one quintillion. Those figures do not identify a source egg and are not a guarantee after that many attempts.
Radar tracks a rarity tier
Eternal Radar tracks Ethereal eggs, while Magic Radar tracks Mythic eggs. The radar list gives prices and target tiers; it does not say radar raises an egg's Luck or any pet's hatch probability.
A safer buying sequence
Pick your desired pet, check whether its source egg is actually documented, inspect candidate egg contents in game, then choose the matching radar by the egg's visible rarity. If the egg-to-pet link is unknown, stop before spending heavily.
Do not convert Luck into odds or infer a pet from egg rarity without a verified table.
Questions players ask
Does higher egg Luck mean a known hatch chance?
No conversion is published in the checked egg and pet sources.
Does radar boost Luck?
The checked radar source describes egg locating by rarity, not a Luck or hatch-rate bonus.