Learn Spanish (Latin America): Hace dos horas que esperamos el eclipse de luna. - We have been waiting for the lunar eclipse for two hours.

In Spanish, when an action started in the past and is still happening right now, you use the present tense. Because we are still waiting for the eclipse, esperamos (we wait) is used alongside the hace + [time] + que structure.

How exactly does hace dos horas que translate to "for two hours"?

Literally, this phrase means "it makes two hours that". This is the standard Spanish formula to express how long an ongoing action has been taking place. You can think of it as saying, "It makes two hours that we are waiting."

Why isn't there a word for "for" after esperamos?

The Spanish verb esperar already means "to wait for" (as well as "to hope" or "to expect"). You don't need to add a word like por or para after it. You just name the thing you are waiting for directly: esperamos el eclipse.

Could I say eclipse lunar instead of eclipse de luna?

Yes, eclipse lunar is perfectly valid and means the exact same thing. However, using de plus a noun (literally "eclipse of the moon") is a very common way in Spanish to build phrases that would be compound nouns or adjective-noun pairs in English.