A documented station. One epoch of record on it. Your own measured detection limit rather than one taken from a book. And a protocol precise enough that somebody else can execute it.
Whether any of that turns out to matter depends on one thing, and it is not the quality of your photography. It depends on someone going back. Most likely you.
The records that turned out to matter most were nearly all made by people who had no idea they would.
Quick check
Three questions, drawn at random from this lesson's set, one attempt each. The right answer is shown either way. Two of three opens the next lesson; fewer and you get another three. Nothing is recorded anywhere but this browser, and this is not the Knowledge Review — it is a way of showing the lesson was read.
Generated from the Reef Chronicler Student Handbook, version 0.04. The course documents are the authority; if these pages and they ever disagree, the documents are right.