CycleCalcs event database: free sample, calendar year 2027 Edition sample-2027, version 1.0.1 This folder is one full year of the CycleCalcs event database, in the same layout as the paid 1900 to 2100 files: one CSV and one JSON file per event family, this README, and SHA256SUMS. 2027 is the sample year because it holds the total solar eclipse of 2 August 2027. LICENSE The values are public domain: CycleCalcs LLC asserts no right in computed values and dedicates any that exists to the public domain under CC0 1.0 (https://www.cyclecalcs.com/LICENSE, clause 3). The files of this free sample, including their selection, arrangement and this README, are also dedicated to the public domain under CC0 1.0 (https://creativecommons.org/publicdomain/zero/1.0/), as recorded in https://www.cyclecalcs.com/NOTICE.md, PART 3. They may be shared, copied and republished freely. That is not true of the paid files: the files delivered with the paid event database may not be redistributed, though the values in them stay public domain. WINDOW AND TIME SCALE Every event with 2027-01-01T00:00:00Z <= instant < 2028-01-01T00:00:00Z. Every instant is UTC, written as ISO 8601 with milliseconds and a Z suffix. The computation runs in Terrestrial Time and converts to UT1 with delta-T from IERS EOP 20 C04 measured through 2025-05-05, IERS Rapid Service finals through 2026-10-08, and IERS Bulletin A XXXIX No. 41 (issued 2026-10-08) predicted through 2027-10-08; after that, a linear blend back to the Espenak and Meeus polynomial. delta-T at the eclipse of 2 August 2027 is 69.4 s. UT1 is taken as UTC (they differ by under 0.9 s). The milliseconds let two editions be compared. They make no accuracy claim. Measured accuracy is under ACCURACY below. ACCURACY Measured in this file against the U.S. Naval Observatory, which prints each instant to the minute, so up to 30 s of any residual below is that rounding: - Equinoxes and solstices: tens of seconds off. The four of 2027 are -12.2, -11.6, -33.1, +17.3 s from the USNO minute (20.5 s RMS, 33.1 s at most). Cross-quarters are found the same way and have no USNO reference. - Moon phases: within a minute. 10 of the 12 full moons of 2027 round to the USNO minute; the largest residual from it is 37.5 s. New moons and quarters come from the same search. - Eclipses: the 2 August 2027 path width, central duration and Sun altitude are within 3 km, 4 s and 0.1 deg of NASA GSFC (see CROSS-CHECK). Peak instants carry the delta-T above. - Stations: published to 2 s, the bracket the engine's own root search achieves. A station is a slow turning point, so the planet barely moves for hours around that instant. - Node crossings and conjunctions: no external reference for 2027 is held; they come from the same engine and the same delta-T. Engine-wide figures, method and references: https://www.cyclecalcs.com/api/accuracy.html SOURCE Every row is the value the CycleCalcs API code returns for the query named in that family's JSON file (source.api_query), API contract 2.4.0, computed with Astronomy Engine 2.1.19 (MIT) by Don Cross, with delta-T from the source named above (source.delta_t_source in each JSON file). The live API returns the same values while it runs the same engine and the same delta-T edition. A delta-T refresh moves every instant by the change in delta-T, and the sample is then reissued under a new version. Conventions and measured accuracy: https://www.cyclecalcs.com/api/accuracy.html Field definitions per endpoint: https://www.cyclecalcs.com/api/reference.html FORMAT CSV: UTF-8, comma separated, one header row, LF line endings. An empty cell means the column does not apply to that row (null in the JSON). JSON: one document per family with the dataset header, the column list with units, and "rows", an array of objects keyed by the CSV column names. Angles are degrees, distances km, durations as named in the column. Ecliptic coordinates are apparent geocentric, of date. FILES Every file in one zip: https://www.cyclecalcs.com/data/event-database/sample-2027.zip Each file on its own: https://www.cyclecalcs.com/data/event-database/sample-2027/ phases.csv / .json 49 rows Moon phases eclipses.csv / .json 5 rows Solar and lunar eclipses seasons.csv / .json 8 rows Equinoxes, solstices and cross-quarters stations.csv / .json 15 rows Planetary stations nodes.csv / .json 27 rows Lunar node crossings conjunctions.csv / .json 115 rows Conjunctions README.txt this file SHA256SUMS checksums of every file above and this README, checked with: sha256sum -c SHA256SUMS PHASES Every new moon, first quarter, full moon and last quarter. Instants are apparent-longitude instants (the Moon minus the Sun at 0, 90, 180 and 270 deg). Supermoon and micromoon use the site rule (closer than 360,000 km, farther than 405,000 km at the phase instant); supermoon_espenak is the competing per-year rule. Names and both blue-moon senses are computed in UTC. - instant_utc [ISO 8601 UTC]: The phase instant. - kind: new_moon, first_quarter, full_moon or last_quarter. - lunation_number: Brown lunation number. - distance_km [km]: Geocentric distance of the Moon at the instant. - angular_diameter_arcsec [arcsec]: Apparent diameter of the Moon at the instant. - illuminated_fraction [0 to 1]: Illuminated fraction of the disk. About 0.5013 at a quarter (the geometric half is 0.5000). - is_supermoon [true/false]: New and full moons only; empty at a quarter. - is_micromoon [true/false]: New and full moons only; empty at a quarter. - supermoon_espenak [true/false]: Espenak (after Nolle) per-calendar-year rule; new and full moons only. - full_moon_name: Traditional (folklore) name; full moons only. - is_blue_moon_monthly [true/false]: Second full moon in a UTC calendar month; full moons only. - is_blue_moon_seasonal [true/false]: Third full moon in an astronomical season holding four; full moons only. - eclipse_type: solar or lunar when this syzygy carries an eclipse; empty otherwise. - eclipse_kind: The eclipse kind, as in eclipses.csv. - eclipse_peak_utc [ISO 8601 UTC]: Peak of that eclipse; it differs from the phase instant by minutes. ECLIPSES Every solar and lunar eclipse whose peak falls in the year, with global circumstances. Solar columns are empty on lunar rows and lunar columns empty on solar rows. The saros member number is not published: it needs catalog data whose license is not yet verified. - peak_utc [ISO 8601 UTC]: Greatest eclipse (solar) or maximum (lunar). - type: solar or lunar. - kind: Solar: partial, annular, total or hybrid. Lunar: penumbral, partial or total. - saros_series: Van den Bergh saros series number, computed in closed form. - gamma [Earth radii]: Least distance of the shadow axis from the Earth's center, signed (positive north). - eclipse_magnitude: Solar only: magnitude at greatest eclipse. - obscuration_fraction [0 to 1]: Solar only: fraction of the Sun's disk covered at greatest eclipse. - greatest_eclipse_latitude_deg [deg]: Solar only: latitude of greatest eclipse, positive north. - greatest_eclipse_longitude_deg [deg]: Solar only: longitude of greatest eclipse, positive east. - central_duration_seconds [s]: Solar central eclipses only: duration of totality or annularity at greatest eclipse. - path_width_km [km]: Solar central eclipses only: path width at greatest eclipse. - sun_altitude_deg [deg]: Solar central eclipses only: the Sun's altitude at greatest eclipse. - umbral_magnitude: Lunar only; negative for a penumbral eclipse. - penumbral_magnitude: Lunar only. - penumbral_minutes [min]: Lunar only: duration of the penumbral phase. - partial_minutes [min]: Lunar only: duration of the partial (umbral) phase; 0 if none. - total_minutes [min]: Lunar only: duration of totality; 0 if none. SEASONS The four equinoxes and solstices and the four true cross-quarters (the Sun at apparent ecliptic longitude 45, 135, 225 and 315 deg; calendar midpoints are not used). The instant is the same everywhere on Earth. - instant_utc [ISO 8601 UTC]: The instant the Sun reaches the defining apparent ecliptic longitude. - kind: equinox_march, solstice_june, equinox_september, solstice_december, or cross_quarter_february, _may, _august, _november. - solar_longitude_deg [deg]: The defining apparent geocentric ecliptic longitude of the Sun (of date). STATIONS Every station of Mercury through Neptune: the instant the apparent geocentric ecliptic longitude of date stops changing, as retrograde motion begins or ends. A station that pairs with one in another year is still listed in the year it falls in. Venus has no station in 2027. - instant_utc [ISO 8601 UTC]: The station instant. Published to 2 s. - body: Mercury, Venus, Mars, Jupiter, Saturn, Uranus or Neptune. - kind: station_retrograde (retrograde motion begins) or station_direct (it ends). - ecliptic_longitude_deg [deg]: Apparent geocentric ecliptic longitude of date at the station. - ecliptic_latitude_deg [deg]: Apparent geocentric ecliptic latitude of date at the station. - constellation: IAU constellation containing the body at the instant. - elongation_from_sun_deg [deg]: Angular distance from the Sun at the instant. - elongation_direction: evening (east of the Sun) or morning (west of the Sun). NODES Every crossing of the ecliptic by the Moon, using the true node: the instant the Moon's geocentric ecliptic latitude passes through zero. - instant_utc [ISO 8601 UTC]: The crossing instant. - kind: node_ascending (moving north) or node_descending (moving south). - node_longitude_deg [deg]: Ecliptic longitude of the Moon, which is the node's longitude, at the crossing. CONJUNCTIONS Every conjunction of a pair among the Sun, Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune, and of the Moon with each planet. The instant is the least apparent geocentric separation in the basin that holds the ecliptic-longitude coincidence; that coincidence instant is listed beside it. The Sun-Moon conjunction is the new moon and is in phases.csv instead. - instant_utc [ISO 8601 UTC]: Instant of least apparent geocentric separation. - body_a: First body of the pair. - body_b: Second body of the pair. - separation_deg [deg]: Least apparent geocentric separation. - ecliptic_longitude_difference_deg [deg]: Longitude of b minus longitude of a at that instant (apparent, of date). - ecliptic_latitude_difference_deg [deg]: Latitude of b minus latitude of a at that instant. - longitude_conjunction_utc [ISO 8601 UTC]: Instant the two apparent ecliptic longitudes are equal. - elongation_from_sun_deg [deg]: Angular distance from the Sun of body_a at the instant (of body_b when body_a is the Sun), as /v2/conjunctions measures it. For a Moon pair it is the Moon's. - elongation_direction: evening or morning, for the same body. - observability: The /v2/conjunctions visibility code from the elongation: glare (under 15 deg), evening_sky, morning_sky, or most_of_night (135 deg or more). CROSS-CHECK Re-checked by tools/check-event-sample.mjs on every build. Independent references: the U.S. Naval Observatory minute for the equinoxes, solstices and full moons (retrieved 2026-09-25), and the NASA GSFC circumstances of 2 Aug 2027. Bounds: seasons 90 s, full moons 60 s, path width 3 km, duration 4 s, Sun altitude 0.1 deg. PASS equinox_march ours 2027-03-20T20:24:47.804Z ref 2027-03-20T20:25Z (USNO equinox) -12.2 s from the USNO minute PASS solstice_june ours 2027-06-21T14:10:48.401Z ref 2027-06-21T14:11Z (USNO solstice) -11.6 s from the USNO minute PASS equinox_september ours 2027-09-23T06:01:26.878Z ref 2027-09-23T06:02Z (USNO equinox) -33.1 s from the USNO minute PASS solstice_december ours 2027-12-22T02:42:17.304Z ref 2027-12-22T02:42Z (USNO solstice) +17.3 s from the USNO minute PASS full moon 2027-01-22 ours 2027-01-22T12:17:21.412Z ref 2027-01-22T12:17Z (USNO) same minute, +21.4 s PASS full moon 2027-02-20 ours 2027-02-20T23:23:37.456Z ref 2027-02-20T23:23Z (USNO) minute differs, +37.5 s PASS full moon 2027-03-22 ours 2027-03-22T10:43:48.078Z ref 2027-03-22T10:44Z (USNO) same minute, -11.9 s PASS full moon 2027-04-20 ours 2027-04-20T22:27:11.669Z ref 2027-04-20T22:27Z (USNO) same minute, +11.7 s PASS full moon 2027-05-20 ours 2027-05-20T10:59:04.361Z ref 2027-05-20T10:59Z (USNO) same minute, +4.4 s PASS full moon 2027-06-19 ours 2027-06-19T00:44:24.439Z ref 2027-06-19T00:44Z (USNO) same minute, +24.4 s PASS full moon 2027-07-18 ours 2027-07-18T15:44:58.135Z ref 2027-07-18T15:45Z (USNO) same minute, -1.9 s PASS full moon 2027-08-17 ours 2027-08-17T07:28:42.130Z ref 2027-08-17T07:29Z (USNO) same minute, -17.9 s PASS full moon 2027-09-15 ours 2027-09-15T23:03:32.822Z ref 2027-09-15T23:03Z (USNO) minute differs, +32.8 s PASS full moon 2027-10-15 ours 2027-10-15T13:46:59.433Z ref 2027-10-15T13:47Z (USNO) same minute, -0.6 s PASS full moon 2027-11-14 ours 2027-11-14T03:25:53.218Z ref 2027-11-14T03:26Z (USNO) same minute, -6.8 s PASS full moon 2027-12-13 ours 2027-12-13T16:08:47.982Z ref 2027-12-13T16:09Z (USNO) same minute, -12.0 s PASS 2027-08-02 path width ours 259.0 km ref 257.7 km (NASA GSFC) +1.3 km PASS 2027-08-02 central duration ours 384.7 s ref 383 s (NASA GSFC, 6m23s) +1.7 s PASS 2027-08-02 Sun altitude ours 81.71 deg ref 81.7 deg (NASA GSFC) +0.01 deg Consistency with the site's own pages. These rows are no independent check: the eclipse catalog and the 2 Aug 2027 page come from the same Astronomy Engine eclipse search as this sample, so they show that the sample and the pages agree. They do not show that either is right. PASS eclipse count 2027 ours 5 ref 5 (eclipses/eclipses.json) equal PASS 2027-02-06 solar annular ours 2027-02-06T15:59:39.357Z ref 2027-02-06T15:59:39.357Z (eclipses/eclipses.json, solar annular, saros 131) identical instant, kind and saros PASS 2027-02-20 lunar penumbral ours 2027-02-20T23:12:50.552Z ref 2027-02-20T23:12:50.552Z (eclipses/eclipses.json, lunar penumbral, saros 143) identical instant, kind and saros PASS 2027-07-18 lunar penumbral ours 2027-07-18T16:03:01.503Z ref 2027-07-18T16:03:01.503Z (eclipses/eclipses.json, lunar penumbral, saros 110) identical instant, kind and saros PASS 2027-08-02 solar total ours 2027-08-02T10:06:41.296Z ref 2027-08-02T10:06:41.296Z (eclipses/eclipses.json, solar total, saros 136) identical instant, kind and saros PASS 2027-08-17 lunar penumbral ours 2027-08-17T07:13:51.626Z ref 2027-08-17T07:13:51.626Z (eclipses/eclipses.json, lunar penumbral, saros 148) identical instant, kind and saros PASS 2027-08-02 greatest eclipse ours 2027-08-02T10:06:41.296Z ref 2027-08-02T10:06:41.296Z (eclipses/2027-08-02-total-solar.html, prints 10:06 UTC) identical Questions: info@cyclecalcs.com