Anything about astronomy. The answer is built only from real NASA Astronomy Picture of the Day (APOD) descriptions, and the pictures behind it are always shown as sources. It covers roughly the last three years of APOD entries.

What is RAG (Retrieval-Augmented Generation)?

Instead of letting the language model answer from memory, the site first retrieves the most relevant real APOD texts and then asks the model to answer only from those. The retrieval grounds the generation, so answers stay tied to real sources instead of being made up.

Why does it only use NASA APOD texts?

Grounding every answer in a fixed, trusted set of texts is the whole point of the demo. It keeps answers honest and lets you check each claim against the source picture, rather than trusting a model's general knowledge.

Honestly, because NASA's open APIs are a genuine pleasure to work with. You get a free API key in seconds, with no approval process and no credit card, and the Astronomy Picture of the Day feed was a perfect fit for a small demo: real, well-written explanations, each paired with a striking image. Get your own key at https://api.nasa.gov/

Why do I sometimes get no direct answer, just closest matches?

If the APOD archive does not actually cover your question, the site shows the closest pictures instead of inventing an answer. That is deliberate: it would rather admit a gap than guess.

What does Smart search do?

With Smart search on, your question is first cleaned up (typos fixed, vague wording tightened) and you pick from the suggested versions before searching. It helps a misspelled or fuzzy query still find matches. Off, your text is searched exactly as typed.

What is Star Trek answer mode?

A playful toggle that gives the answer a Star Trek bridge-officer voice. It changes only the tone, never the facts or the sources.

Is my question stored?

No. Your question is sent to the server only to create the search embedding and the grounded answer. It is not saved to a database or tied to an account, and there is no login or tracking of what you ask.

Why does it sometimes fail or hit a limit?

It runs on free API tiers on purpose, so it can reach Google Gemini's daily quota. When that happens the site says so honestly instead of faking an answer. Try again later, once the quota resets.

What was the motivation behind building something like this?

Nothing ambitious. It is a small project to get a little closer to the big black box that AI and RAG can feel like, no more and no less. I just wanted to understand a bit of what actually happens between a question going in and an answer coming out. And building something like this alongside my day job was simply a lot of fun.

Questions & answers

What this is, and how to use it

A few things worth knowing before you ask: what the site does, why it sometimes says no, and what the two toggles change.

What can I ask here?