Word for a lighthouse enthusiast

Solution 1:

As expected, I didn't find it in OED, but I've no doubt most such people would understand and accept the designation pharologist, derived from...

pharology - the scientific study of lighthouses and signal lights.

EDIT: I broke off for my tea earlier, before getting around to checking other online resources. I still can't find a current dictionary definition, but I see Wikipedia says...

Those who study or are enthused by lighthouses are known as pharologists

...and Collins dictionary has the word filed under "Pending Investigation"

As regards actual usage, it's worth noting that Google Books claims 970 instances of pharologist, and another 48 for the plural (for comparison, they have 3 hits for pharophile and 1 pharophiles).

If anyone wants the etymological background that told me what to look for, this is from OED...

pharos - classical Latin pharos, pharus lighthouse, spec. (as proper name) the lighthouse on the island of Pharos built for Ptolemy II of Egypt, in post-classical Latin also lamp, candelabrum (5th cent.) < Pharos , Pharus (ancient Greek Φάρος&), the name of an island off Alexandria (now a peninsula forming part of the city); compare Hellenistic Greek ϕάρος lighthouse.

Personally I'd say that makes it essentially Greek rather than Latin origin, but others may disagree.

Solution 2:

There is a neologism: pharophile. It is not a common word and it is not in dictionaries. But it is used colloquially.

This word applies to both who likes and studies lighthouses.

For example, this word is used in an Australian website about lighthouses:

We begin a series of "lessons" for lighthouse buffs (pharophiles) on lighthouse technology, physics and chemistry, as written and researched by our LoA Inc President, Denise Shultz, who in a former life was a chemical engineer. This first part of Pharology 101 discusses the mercury float, which was originally used in most lighthouses around the world to support and rotate the lens.