CycleCalcs · Example Payload
Cyclecalcs V2 Moon Example
AstronomySpaceScienceEphemerisSunMoonPlanetsEclipsesTimeCalendarGeolocationMCPAgent-native
Cyclecalcs V2 Moon Example is an example object payload from CycleCalcs, with 9 top-level fields. It illustrates the shape of data this provider's APIs accept or return.
Top-level fields
endpointcomputed_atquerydatawarningslinksmetaattributiondocs
Example Payload
{
"endpoint": "/v2/moon",
"computed_at": "2026-08-01T00:00:00.000Z",
"query": {
"at": "2026-07-27T21:00:00.000Z",
"mode": "instant",
"resolved_from": "at",
"is_now": false,
"latitude": 51.4778,
"longitude": -0.0015,
"elevation_m": 0,
"tz": "Europe/London",
"utc_offset_seconds": 3600,
"utc_offset_iso": "+01:00",
"is_dst": true,
"timezone_source": "parameter",
"day_anchor": "civil",
"time_format": "iso",
"format": "json",
"shape": "nested",
"precision": 6,
"pretty": 1,
"verbosity": "full",
"hemisphere": "north",
"next_phases": 4,
"ignored": []
},
"data": {
"phase": {
"name": "Waxing Gibbous",
"code": "waxing_gibbous",
"emoji": "🌔",
"waxing": true,
"phase_angle_deg": 160.696581,
"phase_angle_convention": "MoonPhase: 0 to 360 degrees of elongation of the Moon from the Sun in ecliptic longitude, increasing from 0 at new moon through 180 at full moon.",
"illumination_phase_angle_deg": 19.582767,
"illumination_phase_angle_convention": "Illumination().phase_angle: 0 to 180 degrees of Sun-Moon-Earth angle, 0 at full moon and 180 at new moon. This is a different quantity from phase_angle_deg and the two are intentionally both returned.",
"illuminated_fraction": 0.971079,
"illumination_percent": 97.1,
"age_days": 13.47,
"age_definition": "Elapsed days since the PREVIOUS new moon, found by the same phase search that produces next_phases. next_phases lists only future phases, so it does not contain this instant.",
"age_days_mean_rate_proxy": 13.18,
"day_of_cycle": 14,
"cycle_length_days": 29.53,
"lunation_number": 1281
},
"bright_limb": {
"position_angle_deg": 250.212861,
"definition": "Position angle of the midpoint of the bright limb, measured from the celestial north pole eastward, at the topocentric place.",
"parallactic_angle_deg": -16.632185,
"orientation_angle_deg": 266.845046,
"orientation_definition": "position_angle_deg minus parallactic_angle_deg, normalised to [0, 360). It is the angle from the observer zenith direction to the midpoint of the bright limb, measured in the same sense as position_angle_deg, which runs counterclockwise in the observer direct view. The zenith sits at position angle parallactic_angle_deg from the body, so to turn a graphic drawn with celestial north up into the observer view, rotate the graphic CLOCKWISE by parallactic_angle_deg (equivalently, counterclockwise by minus parallactic_angle_deg); that brings the zenith to the top, and the bright limb then sits at orientation_angle_deg from vertical in that view. parallactic_angle_deg is positive when the body is west of the meridian."
},
"magnitude": -12.07,
"distance_km": 402537.664653,
"distance_au": 0.002691,
"distance_basis": "topocentric",
"angular_diameter_arcsec": 1780.531953,
"fraction_of_mean_distance": 1.049656,
"fraction_of_mean_distance_definition": "The geocentric Earth-Moon centre distance divided by the mean distance of 384400 km. Geocentric by construction, so it is a property of the orbit and does not change with the observer.",
"libration": {
"longitude_deg": -1.393572,
"latitude_deg": 4.814328,
"favoured_limb": "west",
"note": "The value is the sub-Earth selenographic longitude, positive east under the IAU convention. Positive favours the eastern limb, the Mare Crisium side; negative favours the western limb, toward Grimaldi and Mare Orientale. Selenographic east is the opposite side of the disc from sky east. A value within 0.5 deg of zero is reported as none, because no limb is meaningfully favoured there."
},
"tropical_sign": {
"name": "Capricorn",
"code": "capricorn",
"sign_index": 9,
"degree_in_sign": 15.548204,
"degree_in_sign_whole": 15
},
"constellation": {
"name": "Sagittarius",
"abbreviation": "Sgr"
},
"position_geocentric": {
"equatorial": {
"j2000": {
"ra_hours": 19.128459,
"ra_string": "19h 07m 42.5s",
"dec_deg": -26.205724,
"dec_string": "-26 12 20.6"
},
"of_date": {
"ra_hours": 19.156001,
"ra_string": "19h 09m 21.6s",
"dec_deg": -26.163895,
"dec_string": "-26 09 50.0"
}
},
"ecliptic": {
"true_of_date": {
"longitude_deg": 285.548204,
"latitude_deg": -3.656979
}
},
"distance_au": 0.002697,
"distance_km": 403487.831539,
"distance_light_minutes": 0.022432,
"origin": "geocentric"
},
"position_topocentric": {
"equatorial": {
"j2000": {
"ra_hours": 19.147396,
"ra_string": "19h 08m 50.6s",
"dec_deg": -27.063727,
"dec_string": "-27 03 49.4"
},
"of_date": {
"ra_hours": 19.17511,
"ra_string": "19h 10m 30.4s",
"dec_deg": -27.021187,
"dec_string": "-27 01 16.3"
}
},
"ecliptic": {
"true_of_date": {
"longitude_deg": 285.700348,
"latitude_deg": -4.538803
}
},
"horizontal": {
"azimuth_deg": 155.832838,
"compass": "SSE",
"altitude_refracted_deg": 8.076611,
"altitude_unrefracted_deg": 7.966211,
"refraction_deg": 0.110401,
"hour_angle_hours": 22.195103,
"parallactic_angle_deg": -16.632185
},
"distance_au": 0.002691,
"distance_km": 402537.664653,
"distance_light_minutes": 0.022379,
"origin": "topocentric",
"observer_height_m": 0
},
"parallax_deg": 0.894787,
"window": {
"start": "2026-07-27T00:00:00.000+01:00",
"end": "2026-07-28T00:00:00.000+01:00",
"anchor": "civil",
"length_minutes": 1440,
"local_date": "2026-07-27"
},
"rise_set": {
"status": "normal",
"status_label": "Rises and sets",
"events": [
{
"kind": "set",
"instant": "2026-07-27T02:22:25.658+01:00",
"azimuth_deg": 221.893959,
"altitude_deg": -0.812725
},
{
"kind": "lower_transit",
"instant": "2026-07-27T11:25:36.503+01:00",
"azimuth_deg": 359.999926,
"altitude_deg": -65.724457
},
{
"kind": "rise",
"instant": "2026-07-27T20:18:10.269+01:00",
"azimuth_deg": 135.541217,
"altitude_deg": -0.81339
},
{
"kind": "upper_transit",
"instant": "2026-07-27T23:50:53.040+01:00",
"azimuth_deg": 179.999799,
"altitude_deg": 11.72421
}
],
"rise": [
"2026-07-27T20:18:10.269+01:00"
],
"set": [
"2026-07-27T02:22:25.658+01:00"
],
"transit": [
"2026-07-27T23:50:53.040+01:00"
],
"above_horizon_minutes": 364.3
},
"event_definition": "upper limb at the horizon, with topocentric parallax and refraction applied by the engine's own rise and set search",
"next_phases": [
{
"code": "full_moon",
"name": "Full Moon",
"instant": "2026-07-29T15:36:19.011+01:00",
"days_until": 1.73
},
{
"code": "last_quarter",
"name": "Last Quarter",
"instant": "2026-08-06T03:21:58.672+01:00",
"days_until": 9.22
},
{
"code": "new_moon",
"name": "New Moon",
"instant": "2026-08-12T18:37:11.343+01:00",
"days_until": 15.86
},
{
"code": "first_quarter",
"name": "First Quarter",
"instant": "2026-08-20T03:46:58.247+01:00",
"days_until": 23.24
}
],
"summary": "The Moon is a waxing gibbous, 97.1 percent lit, 13.5 days into its cycle. It sets at 02:22 and rises at 20:18 local time."
},
"warnings": [],
"links": {
"self": "https://www.cyclecalcs.com/v2/moon?at=2026-07-27T21%3A00%3A00Z&lat=51.4778&lon=-0.0015&tz=Europe%2FLondon",
"docs": "https://www.cyclecalcs.com/api/reference.html#moon",
"spec": "https://www.cyclecalcs.com/v2/openapi.json",
"page": "https://www.cyclecalcs.com/moon-phase-calendar.html",
"explain": "https://www.cyclecalcs.com/learn/moon-phases.html",
"related": [
{
"rel": "cycle",
"title": "The synodic month",
"href": "https://www.cyclecalcs.com/cycles/synodic-month.html"
},
{
"rel": "cycle",
"title": "The anomalistic month",
"href": "https://www.cyclecalcs.com/cycles/anomalistic-month.html"
}
]
},
"meta": {
"api_version": "2",
"contract_version": "2.0.0",
"engine": {
"name": "Astronomy Engine",
"license": "MIT",
"author": "Don Cross",
"version": "2.1.19",
"version_source": "upstream_sha256_match",
"sha256": "068f1445ed0c636c94818fe6d20d7d125120e605e0bab9fc4675c3d531be5ad7",
"vendored": true,
"credit": "astronomy-engine (MIT, Copyright (c) 2019-2023 Don Cross)"
},
"tzdb": "2026b",
"rights": "unrestricted",
"attribution": {
"required": false,
"text": "Computed by CycleCalcs (cyclecalcs.com) with the MIT-licensed Astronomy Engine. Positional astronomy only.",
"sources": []
},
"notice_url": "https://www.cyclecalcs.com/methodology.html#data-sources",
"cache": {
"class": "fixed_instant",
"deterministic": true
},
"accuracy": {
"statement": "Positions are arcminute class for the Sun, Moon and planets across 1700 to 2200, degrading toward the ends of that window.",
"residuals_url": "https://www.cyclecalcs.com/api/accuracy.html"
},
"time": {
"scale_of_input": "UTC",
"ut1_source": "assumed equal to UTC; no IERS bulletin is loaded, so UT1 minus UTC may differ by up to 0.9 s",
"delta_t_seconds": 75.4,
"delta_t_model": "Espenak and Meeus"
},
"corrections": {
"aberration": true,
"light_travel_time": true,
"nutation": true,
"topocentric_parallax": true,
"proper_motion": false,
"polar_motion": false
},
"conventions": {
"synodic_month_days": 29.530588853,
"mean_distance_km": 384400
},
"not_computed": [
{
"name": "constellation.genitive",
"reason": "Needs the reduced constellation index; the generator has not run yet."
}
],
"refraction": {
"model": "Saemundsson (Astronomy Engine normal mode)",
"verified": true,
"applied_below_horizon_down_to_deg": -1,
"note": "Applied to the refracted altitude in every horizontal block. The unrefracted altitude and the difference are published beside it, so this endpoint has no refraction parameter to switch off."
},
"budget": {
"engine_calls": 37
}
},
"attribution": "Computed by CycleCalcs (cyclecalcs.com) with the MIT-licensed Astronomy Engine. Positional astronomy only.",
"docs": "https://www.cyclecalcs.com/api/reference.html#moon"
}