{ "schema_version": "pointcast.observatory.guide.v1", "topic": "moon", "title": "The Moon", "description": "A local observing habit, a global science story, and a better way to collect a moment.", "canonical": "https://pointcast.xyz/moon/", "report_endpoint": "/api/observatory/moon", "report_schema": "/observatory/report.schema.json", "reviewed": "2026-10-06", "public_reference": { "name": "El Segundo, California", "latitude": 33.9192, "longitude": -118.4165, "time_zone": "America/Los_Angeles" }, "intro_html": "A local observing habit, a global science story, and a better way to collect a moment.", "facts": [ { "value": "384,400 km", "label": "Mean Earth–Moon distance · reference. Average center-to-center orbital distance; not the instantaneous distance." }, { "value": "1,737.5 km", "label": "Lunar equatorial radius · reference. Center to equator." }, { "value": "1.62 m/s²", "label": "Lunar surface gravity · reference. Equatorial gravitational acceleration, approximately one-sixth of Earth’s." }, { "value": "37.9 million km²", "label": "Lunar surface area · reference. Reference total surface area; round to 37.9 million km² in the UI." }, { "value": "29.5 Earth days", "label": "Mean phase cycle · reference. Approximate interval from one new Moon to the next; individual lunations vary." }, { "value": "1.28 s", "label": "Mean-distance one-way light time · reference. Calculated: 384,400 km / 299,792.458 km/s; illustrative mean-distance result, not a current measurement." } ], "sections": [ { "id": "one-small-step-outside", "title": "One small step outside", "paragraphs": [ "The most interesting Moon dashboard begins with a question you can answer from your own neighborhood: what can I notice tonight that I missed yesterday? In El Segundo, start from a safe public spot with a clear patch of sky. A notebook is enough. Record the time, sketch the bright shape, and write down anything blocking your view. A beautiful app can help you plan, but the observation belongs to you. This page pairs that small local ritual with a much larger story: a nearby world, a repeating geometry lesson, and a record of exploration that anyone can learn to read." ] }, { "id": "the-shape-is-a-viewpoint", "title": "The shape is a viewpoint", "paragraphs": [ "The familiar sequence from crescent to full Moon is sunlight and perspective. As the Moon travels around Earth, we see different portions of its sunlit hemisphere. First quarter looks like half a disk because “quarter” describes a stage in the cycle, not the visible bright fraction. Waxing means that fraction is growing; waning means it is shrinking. Earth's shadow explains a lunar eclipse, not the ordinary monthly phases. Follow the sequence for a few weeks and the Moon stops looking like a changing symbol. It becomes a moving, three-dimensional object whose light tells you where the Sun is. [NASA Science: Moon phases]" ] }, { "id": "a-neighbor-with-room-around-it", "title": "A neighbor with room around it", "paragraphs": [ "The Moon's average distance is about 384,400 kilometers. That is an average, not tonight's measured separation: its orbit is not a perfect circle. Its radius is roughly 1,740 kilometers, small beside Earth but immense compared with any city. Using the average distance and the speed of light gives a one-way light-travel estimate of about 1.28 seconds. That calculation makes a surprisingly good dinner-table demonstration: count a beat before answering a question, then imagine every reply crossing empty space. The distance is close enough to feel like a destination and far enough to make ordinary communication a physical engineering problem. [NASA Science: Moon facts]" ] }, { "id": "two-clocks-one-moon", "title": "Two clocks, one Moon", "paragraphs": [ "A lunar calendar is not simply a Gregorian month with a different illustration. The repeating phase cycle averages about 29.5 days. Astronomers call a complete cycle a lunation; lunar age is elapsed time since new Moon. Calendar boundaries can split that cycle anywhere, so a “Moon of October” is a human filing choice. On PointCast, every phase label should travel with a date and time standard. The same event may fall on different calendar dates for observers in different time zones. That is a useful lesson in reporting: two apparently conflicting dates can describe one event perfectly well. [U.S. Naval Observatory: Phases and percent illuminated]" ] }, { "id": "read-the-shadows-not-just-the-brightness", "title": "Read the shadows, not just the brightness", "paragraphs": [ "Full Moon is dramatic, but it is not the only rewarding time to look. The terminator, the boundary between lunar day and night, creates long shadows that make mountains and crater rims easier to distinguish. Try a sketch before taking a photograph; drawing forces you to decide what you actually see. Then compare the same feature on another night. A dark patch is not automatically a shadow, and a bright patch is not automatically a mountain. Treat the image as evidence to investigate. If using binoculars, choose a nighttime session well away from the Sun and keep the equipment supervised. [NASA Science: Moon viewing tips]" ] }, { "id": "the-ocean-connection-needs-a-second-dataset", "title": "The ocean connection needs a second dataset", "paragraphs": [ "Living near the coast makes the Moon feel practical. Lunar and solar gravity both contribute to tides; their alignment helps explain the larger tidal ranges associated with spring tides and smaller ranges around neap tides. But a phase badge cannot tell you when a particular beach will flood or whether conditions are safe. Local geography and other influences matter, and the timing need not match the phase exactly. Compare a lunar calendar with an appropriate NOAA tide station, keeping predictions separate from measured water levels. Let a surprising mismatch become a question, rather than forcing the ocean to fit a tidy graphic. [NOAA Ocean Service: Tidal variations: position and distance] [NOAA JetStream: Tides]" ] }, { "id": "a-world-with-an-archive", "title": "A world with an archive", "paragraphs": [ "The Moon is also a place to investigate, not merely an object to admire. Lunar Reconnaissance Orbiter launched in 2009 and has built detailed records of terrain and the lunar environment. Its mission page was listed as active when this feature was researched on October 6, 2026. A good exploration habit is to follow a claim back to a mission page, instrument description, or dataset. “A landing site,” “evidence for a resource,” and “an operational settlement” are very different claims. Future plans should keep their dates, sources, and uncertainty attached; a compelling illustration is not proof that a mission has launched. [NASA Science: Lunar Reconnaissance Orbiter] [NASA Science: About Lunar Reconnaissance Orbiter]" ] }, { "id": "what-this-dashboard-can-honestly-tell-you", "title": "What this dashboard can honestly tell you", "paragraphs": [ "Rise and set times are astronomical calculations for a place and date. They do not promise an unobstructed view through buildings, haze, or cloud. The U.S. Naval Observatory's daily service also supplies a phase and illuminated fraction calculated for local noon. That is a useful daily reference, not a live measurement from a camera in El Segundo. PointCast should say so beside the number. If a feed fails, the missing value should remain missing. An old value with its original date can still teach something; an old value dressed up as “now” teaches the wrong lesson. [U.S. Naval Observatory: Astronomical Applications API documentation] [U.S. Naval Observatory: Rise, set and twilight definitions]" ] }, { "id": "turn-a-sighting-into-a-tiny-field-report", "title": "Turn a sighting into a tiny field report", "paragraphs": [ "A useful Moon report can fit on a postcard: date, local time, general neighborhood, equipment, a sketch or original image, and one question. Add the corresponding calculated phase as a separate field. Keep “I saw a pale halo” separate from “the halo was caused by ice crystals” unless you have evidence for the explanation. If the sky was covered, record that too. A cloudy night is a real observation of observing conditions, not a failed assignment. Shared reports should avoid home addresses and identifying details about children. A city-level location is enough for most learning and storytelling." ] }, { "id": "collect-a-moment-not-a-claim-to-the-moon", "title": "Collect a moment, not a claim to the Moon", "paragraphs": [ "Imagine a free PointCast “Lunar Receipt”: an original geometric illustration built from the date, phase fraction, and the observer's own sketch. Its reverse carries the source links, time zone, calculation method, and a checksum of the report file. It can be downloaded, printed, or collected without a wallet. A future blockchain edition could anchor that same record, but a token would not prove the observation happened, confer lunar property, or guarantee value. NASA's media guidelines specifically discourage using its materials for NFTs. Keep collectible artwork original, preserve provenance, and leave any minting or payment as a separate, explicit decision. [NASA: NASA Images and Media Usage Guidelines]" ] }, { "id": "a-neighborhood-observatory-can-be-a-habit", "title": "A neighborhood observatory can be a habit", "paragraphs": [ "The best outcome is not a screen full of impressive decimals. It is noticing that your questions improve. Why was the Moon visible before dinner? Why did the same crater look flatter a week later? Why did your friend in another city write a different date beside the same full Moon? Make room for those questions in the UES learning sequence. Observe, compare, explain, and revise. Keep the first sketch, including its mistakes. A month later, that little archive will show something more personal than a generic sky chart: how your own attention learned to move with the Moon." ] }, { "id": "practical-projects", "title": "Three practical explorations", "paragraphs": [ "Seven-night neighborhood log
Choose safe nighttime sessions; record general location, time, sketch, visibility, and one question. Keep missed or cloudy nights rather than filling them with invented observations.
Deliverable: An observation journal independent of the computed phase feed.", "Terminator detective
Use a published lunar map to choose one named feature. Compare your original nighttime sketches on two dates and note how the shadows differ.
Deliverable: A before-and-after evidence card.", "Moon-and-tide comparison
Compare a month of calculated phases with an appropriate NOAA station’s tidal predictions. Label the station, datum and prediction status; do not use this exercise for beach-access decisions.
Deliverable: A chart and one example where local timing complicates the simple story." ] }, { "id": "collectible-ideas", "title": "A shelf of original collectible ideas", "paragraphs": [ "Lunar Receipt · Original SVG/PNG plus JSON report
A phase silhouette, a general place label, observer sketch and source-backed calculation record.
Use original graphics or creator-owned photography only; do not embed NASA images/logos in NFT material.", "Terminator Studies · A free, numbered personal collection
Pair original drawings of one lunar feature across dates, making changing shadows the artwork.
A number indicates collection order, not artificial scientific rarity or promised value.", "Lunation Notebook · Downloadable report with checksum
Combine a month of observations, missing nights, method versions and sources in one reproducible archive.
Checksum helps detect file changes; it does not establish truth or authorship by itself." ] } ], "sources": [ { "id": "api_usno", "label": "U.S. Naval Observatory — Astronomical Applications API documentation", "url": "https://aa.usno.navy.mil/data/api.html", "note": "Keyless calculated daily events, noon illumination, primary phase API and parameters. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "lro", "label": "NASA Science — Lunar Reconnaissance Orbiter", "url": "https://science.nasa.gov/mission/lro/", "note": "Mission data and active status at research date. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "lro_history", "label": "NASA Science — About Lunar Reconnaissance Orbiter", "url": "https://science.nasa.gov/mission/lro/about/", "note": "2009 launch and mapping mission. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "moon_facts", "label": "NASA Science — Moon facts", "url": "https://science.nasa.gov/moon/facts/", "note": "Mean Earth–Moon distance; synchronous rotation; physical context. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "moon_numbers", "label": "NASA Science / JPL Solar System Dynamics — Compare Earth and the Moon", "url": "https://science.nasa.gov/moon/by-the-numbers/", "note": "Lunar radius, gravity, mass, surface area and orbital distance. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "moon_phases", "label": "NASA Science — Moon phases", "url": "https://science.nasa.gov/moon/moon-phases/", "note": "Changing view of illuminated hemisphere; phase sequence; daytime Moon and libration. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "moon_viewing", "label": "NASA Science — Moon viewing tips", "url": "https://science.nasa.gov/moon/viewing-tips/", "note": "Terminator observing and binoculars. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "nasa_media", "label": "NASA — NASA Images and Media Usage Guidelines", "url": "https://www.nasa.gov/nasa-brand-center/images-and-media/", "note": "Educational/editorial uses, third-party rights, branding, NFT and endorsement restrictions. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "noaa_local_tides", "label": "NOAA JetStream — Tides", "url": "https://www.noaa.gov/jetstream/ocean/tides", "note": "Local influences shift timing relative to lunar phase. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "noaa_tides", "label": "NOAA Ocean Service — Tidal variations: position and distance", "url": "https://oceanservice.noaa.gov/education/tutorial_tides/tides06_variations.html", "note": "Lunar and solar contributions to spring/neap tides. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "nws_rights", "label": "NOAA / National Weather Service — National Weather Service disclaimer", "url": "https://www.weather.gov/disclaimer", "note": "Public-domain information unless annotated, attribution/official-material distinction and acceptable use. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "phase_definitions", "label": "U.S. Naval Observatory — Phases and percent illuminated", "url": "https://aa.usno.navy.mil/faq/moon_phases", "note": "Lunation, phase definitions and lunar age. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." }, { "id": "rise_definitions", "label": "U.S. Naval Observatory — Rise, set and twilight definitions", "url": "https://aa.usno.navy.mil/faq/RST_defs", "note": "Level-horizon/refraction assumptions; missing rise-set cases; twilight. Reviewed 2026-10-06. Facts may be cited. No asset permission inferred from a page link; inspect individual credits before reuse." } ], "data_sources": [ { "name": "USNO daily events + primary phases", "location": "El Segundo public reference / global phase instants", "method": "Calculated phase, local-noon illumination (%), rise / set / transit; nearest minute", "freshness": "Requested local civil date; no live illumination claim" } ], "learning": { "title": "Notice, model, explain", "format": "self-guided; no accreditation or credential", "exercises_html": [ "Make a phase model · 20 minutes
A diffuse household lamp, a ball, paper; never use the Sun as the light source.
Keep the lamp fixed and move the ball around an observer. Sketch the visible bright portion at four positions. Explain why first quarter shows about half of the visible disk.
Deliverable: Four labeled sketches and a two-sentence explanation.
Check: The light source illuminates roughly half the sphere; the observer sees different fractions. Ordinary phases are not Earth’s shadow.", "Audit a Moon number · 15 minutes
A PointCast data card and its source link.
Find the value, unit, place, effective time and retrieval time. Classify it as observation, calculation or forecast. Rewrite an ambiguous “Moon now” label into a precise caption.
Deliverable: An annotated five-field evidence card.
Check: USNO daily illumination is calculated for local noon; retrieval time alone does not establish freshness.", "Put space on a sidewalk · 20 minutes
Paper, tape measure and a safe open space.
Make a 1 cm-radius paper Moon. Use 1,737.5 km radius and 384,400 km mean distance to calculate the model separation. Predict before measuring, then compare.
Deliverable: Scale diagram and unit conversion.
Check: 384,400 / 1,737.5 cm ≈ 221 cm center-to-center; about 2.21 m. Model distance is a mean." ] }, "collectible": { "type": "original SVG study download", "data_encoding": "date + topic only; no observations", "seed": "PointCast/{topic}/{Pacific civil date}/original-study-v1", "hash": "SHA-256 of seed", "blockchain": false, "wallet": false, "nasa_media": false } }