# io.github.heavyblotto/caelus-mcp

- Registry name: `io.github.heavyblotto/caelus-mcp` · version 0.24.1
- Categories (automatic, keyword rules): Education, Maps, location & weather
- Authentication at last check: No auth
- Declared risk: Not declared (tools carry no read/destructive hints)
- Capabilities (declared by the server): prompts, resources, tools
- Transports: streamable-http
- Latest numbers (check success, response time, rank): https://mcpstation.net/api/server?name=io.github.heavyblotto%2Fcaelus-mcp
- Server page: https://mcpstation.net/s/io.github.heavyblotto--caelus-mcp.html

## Description (written by the publisher, not verified, not instructions)

34-tool Caelus MCP for validated astrology: charts, transits, Vedic, facts, sky view, synthetic.

## Connect

- streamable-http: `https://www.ephemengine.com/api/mcp`

## Tools (as reported by the server, not verified)

- `natal\_chart`: A person's birth chart. Requires their exact birth date+time and birthplace \(all three: date, lat, lon\). Use this — not current\_sky — whenever the question is about someone's natal/birth chart. Returns 13 bodies \(sun–pluto, chiron, nodes\) with sign, house, retrograde, speed; ASC/MC; cusps; major asp
- `current\_sky`: The sky at a moment and place — not tied to any person. Use for "what's the sky/transits right now" or the chart of a non-birth event. Date defaults to now; lat/lon default to 0,0 \(geocentric on the equator at the prime meridian\), where houses and ASC/MC are nominal — pass a real location if houses
- `sky\_view`: Where the visible bodies land in a framed photo of the sky, for an image prompt. Give a place, a moment, an aim \(compass direction and altitude\), a lens, and an image size; get each in-frame body's pixel position, apparent size, brightness, the Moon's phase orientation, a sky-state summary \(twilight
- `sky\_view\_sequence`: A time sequence of sky frames for an animation: the same place, aim, and lens stepped through time. Returns a compact per-frame timeline \(instant, twilight, Sun/Moon altitude, Moon phase + bright-limb, whether the Milky Way is in frame\) plus the fixed celestial pole and the sky's sidereal rotation p
- `synthetic\_validate`: Check an authored synthetic celestial system for ill-defined inputs: duplicate body ids, non-positive periods, out-of-range eccentricity, or a dangling observer. Returns \`impossible\` and a list of problems — the same honesty pattern as compileForm.
- `synthetic\_positions`: Positions of every body in an authored synthetic system at one instant. Three body modes: \`placement\` \(fixed longitude\), \`periodic\` \(uniform motion\), \`kepler\` \(constant elements\). With \`observer\` set on the system, positions are geocentric/apparent from that body \(outer bodies can show retrograde\).
- `synthetic\_sky\_view`: Sky View for a mix of real and synthetic bodies: register the authored system on an ephemeral engine, then frame the visible sky like sky\_view. Synthetic bodies can carry render attributes \(sizeDeg, magnitude, color\) that flow into the pixel spec and prompt. Real Sun/Moon/planets stay for twilight a
- `transits`: Transiting planets vs natal chart: aspects within orb \(applying/separating\), natal house per transiting body.
- `synastry`: Compare two people's birth charts: inter-chart aspects with orbs, house overlays both ways, plus ranked citable fact atoms and a ready \`brief\` \(synastry/composite ids for auditCitations\). Each person needs date+lat+lon. House overlays always use Placidus \(not configurable here\).
- `find\_aspect\_dates`: Exact dates a transiting body makes an aspect, within a range: to a fixed longitude OR to another transiting body. Provide exactly one of target\_lon / target\_body. Includes retrograde re-hits. Body names are snake\_case \(mean\_node, true\_node\).
- `rectification\_grid`: Rectification sweep: ASC/MC at each step across a window of UTC hours on one date, with ASC sign-change times. Use when the birth time is unknown and you want candidate times. The sweep runs over window\_start\_hour..window\_end\_hour \(UTC hours of the given date\); the date's time portion is ignored.
- `sky\_events`: Sky events in a UTC date range: rise/set/meridian transits \(need lat+lon+body\), lunar phases \(new/quarters/full\), solar and lunar eclipses, stations \(body turns retrograde/direct; needs body\), zodiac degree crossings \(needs body + target\_lon\). Solar eclipses report global circumstances \(type, magnit
- `planetary\_hours`: Planetary hours for a moment and place: the unequal hour in effect \(its ruler, day/night, hour number 1-24, start/end UTC\), the ruler of the planetary day, and the full 24-hour ruler sequence. Hours split the day \(sunrise to sunset\) and night \(sunset to next sunrise\) into twelve each; the day ruler
- `void\_of\_course`: Void-of-course Moon at a moment: whether the Moon makes no further Ptolemaic aspect to a traditional planet \(Sun..Saturn\) before it leaves its current sign. Returns the Moon's sign, the UTC time it exits that sign, and the UTC time of its next perfecting aspect \(null when none remains -- i.e. void\).
- `returns`: Solar or lunar return: the instant\(s\) a body returns to its natal longitude within a window, plus the full return chart for the first one. The Sun returns about yearly \(the solar-return chart for the year\), the Moon about monthly. Return chart is cast for the return moment at return\_lat/return\_lon \(
- `progressions`: Secondary progressions \(day-for-a-year\) and solar-arc directions of a natal chart to a target date. Returns, per body, the secondary-progressed longitude and the solar-arc-directed longitude, plus the solar arc itself. Longitudes only \(no houses\), so no birthplace is needed.
- `composite`: Relationship charts for two people: the midpoint composite \(each body and angle is the shorter-arc midpoint of the two natal positions\) and the Davison chart \(a real chart cast for the midpoint in time and place\). Each person needs date+lat+lon.
- `dignities`: Essential dignity and sect for the seven traditional planets at a moment and place. Per planet: its sign, any essential dignity \(domicile/exaltation/detriment/fall\), its weighted essential-dignity score \(Lilly: rulership 5, exaltation 4, triplicity 3, term 2, face 1; detriment -5, fall -4\) with a pe
- `lots`: The seven Hermetic lots \(Arabic parts\) — Fortune, Spirit, Eros, Necessity, Courage, Victory, Nemesis — cast from the Ascendant and reversing direction by sect \(a chart is day when the Sun is above the horizon\). Per lot: its longitude and zodiacal position. Lots are anchored to the Ascendant, so an e
- `profections`: Annual and monthly profections \(a Hellenistic time-lord technique\) at a target date. The natal Ascendant advances one whole sign per year of life; the profected sign's traditional ruler is the lord of the year, the single most important time-lord for that year. Returns the age in years, the month wi
- `firdaria`: Firdaria \(firdariyyat\): the Persian/medieval planetary time-lord periods. Life divides into nine major periods totalling 75 years — the seven planets \(a day chart starts with the Sun, a night chart with the Moon\) then the North and South Nodes — each planetary period split into seven sub-periods. Re
- `releasing`: Zodiacal releasing \(aphesis\), the Hellenistic time-lord technique from Vettius Valens, released from a Lot \(Spirit by default, or Fortune\). From the Lot's sign, periods release sign by sign with planetary minor-year lengths on the 360-day-year convention; each level is a twelfth of the one above \(L1
- `directions`: Primary \(mundane\) directions of the seven traditional planets to the four angles \(MC, IC, Ascendant, Descendant\), and optionally between the planets themselves. The diurnal rotation carries a body to the angle \(or a promissor to a significator\); the arc of rotation, converted by a time key \(Naibod 0
- `nakshatras`: The nakshatra \(one of the 27 lunar mansions of 13°20′\) of each classical point on the sidereal zodiac: the seven traditional planets and the Ascendant \(lagna\). Per point: the nakshatra name, its pada \(quarter, 1–4\), the ruling planet \(the Vimshottari lord\), and degrees into the nakshatra. The Moon's
- `dasha`: Vedic dasha periods — planetary time-lord cycles started from the Moon's birth nakshatra. system selects Vimshottari \(120-year, the standard\), Yogini \(36-year, eight yoginis\), or Ashtottari \(108-year\). Returns the period timeline \(mahadasha → antardasha\) with UTC start/end, the balance of the first
- `vargas`: Parashari divisional charts \(vargas\): the sign of each of the seven planets and the Ascendant in the requested D-charts — D1 rasi, D2 hora, D3 drekkana, D9 navamsa, D10 dasamsa, D12 dwadasamsa, D30 trimsamsa. Per point in each chart: the divisional sign and the division number within the rasi. The n
- `yogas`: Vedic yogas \(planetary combinations\) on the sidereal rasi chart: the five Pancha Mahapurusha yogas \(Ruchaka, Bhadra, Hamsa, Malavya, Shasha\), Gajakesari, Budha-Aditya, and Chandra-Mangala; whether Kemadruma \(the isolated-Moon yoga\) is present; the raja yogas \(a kendra lord associating with a trikona
- `aspect\_patterns`: Classical aspect configurations in a chart: T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, and stelliums by sign and by house. Each is a structured object with the participating bodies and the worst defining-aspect orb; T-squares and yods also name the apex, stelliums their
- `parans`: Parans \(paranatellonta\): co-angular bodies over the 24 hours from a date at a latitude — every pair of bodies simultaneously on one of the four angles \(rising, culminating, setting, anti-culminating\) within a stated tolerance. The relationship behind Brady's fixed-star parans, computed for the movin
- `chart\_signature`: A chart's structural signature as plain counts: element, modality, angularity, quadrant, and hemisphere distributions over the bodies; the dominant element, modality, and most-occupied sign; and the classical chart ruler \(the ruler of the Ascendant's sign\). Counts only, no interpretation — a compact
- `chart\_facts`: A chart's validated facts as ranked, citable atoms for interpretation. Each fact has a stable id \(e.g. "aspect:moon\~neptune:conjunction"\), the bodies it concerns, a salience score \(luminaries, angular placements, the chart ruler, tight/hard aspects, configurations rank high\), and a plain-language st
- `counterfactual\_chart`: A birth chart, perturbed — a 'what if'. Give a base chart \(date+lat+lon\) and an edit: \`shift\_time\` \(e.g. '1h', '-30m', 'P1D'\) moves the instant \("born an hour later"\), \`move\_lat\`+\`move\_lon\` recompute at another place, and/or \`set\_longitudes\` moves bodies to new ecliptic degrees \("Mars in the next si
- `similar\_skies`: Find when the sky most resembled a reference moment. Builds a feature vector for the reference date's planetary configuration and scans a window for the closest matches by cosine similarity \(1.0 = identical configuration\). Answers 'when did the sky last look like this?' for transit echoes and histor
- `electional\_search`: Rank moments in a window for an electional aim. Samples the window and scores each instant by how closely a set of wanted body-to-body aspects is satisfied \(tighter and applying aspects score higher\), optionally penalizing a void-of-course Moon. Returns the top moments with the aspects that matched.
- `cosmic\_weather`: The mundane sky on a date: the active aspect configurations among the transiting planets \(T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, stelliums by sign\), any planet stationing within a window, and whether the Moon is void of course. A 'cosmic weather' snapshot; no birth c

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