# Star data and credits

Credit: ESA. ESA, 1997, The Hipparcos and Tycho Catalogues, ESA SP-1200. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.

Hipparcos factual columns only, retrieved 2026-11-14T19:26:22.864Z through VizieR I/239/hip_main: https://vizier.cfa.harvard.edu/viz-bin/asu-tsv?-source=I/239/hip_main&-out=HIP,RAICRS,DEICRS,Vmag,B-V,pmRA,pmDE&Vmag=%3C3.1&-out.max=300. Epoch J1991.25 propagated to J2000 using the supplied proper motions. No catalogue descriptions or annotations are included. Catalogue selection: 150 brightest entries with V < 3.1, including every entry V <= 1.7.

ESA terms: https://www.cosmos.esa.int/web/hipparcos/catalogues states CC BY-NC 3.0 IGO and requires Credit: ESA. https://creativecommons.org/licenses/by-nc/3.0/igo/deed.en . This app is distributed without charge; a commercial reuse would require separate review of the noncommercial restriction. No public-domain claim is made.

SIMBAD independent positions: https://simbad.cfa.harvard.edu/simbad/sim-tap/sync?request=doQuery&lang=adql&format=json&query=SELECT%20i.id%2Cb.ra%2Cb.dec%20FROM%20basic%20b%20JOIN%20ident%20i%20ON%20b.oid%3Di.oidref%20WHERE%20i.id%20IN%20('HIP%2032349'%2C'HIP%2030438'%2C'HIP%2069673'%2C'HIP%2071683'%2C'HIP%2091262'%2C'HIP%2024608'%2C'HIP%2024436'%2C'HIP%2037279'%2C'HIP%207588'%2C'HIP%2027989'%2C'HIP%2068702'%2C'HIP%2097649'%2C'HIP%2060718'%2C'HIP%2021421'%2C'HIP%2065474'%2C'HIP%2080763'%2C'HIP%2037826'%2C'HIP%20113368'%2C'HIP%2062434'%2C'HIP%20102098'%2C'HIP%2049669'). CDS redistribution-specific conditions were not independently confirmed; only 21 factual coordinate pairs are included in development test fixtures, with CDS acknowledgement.

Official star names: IAU Division C Working Group on Star Names, https://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt, retrieved 2026-11-15; IAU products are CC BY with source attribution as stated in that file. Only proper-name facts are transcribed. Japanese common names are independently transcribed; less familiar names retain the IAU spelling.

BSC5 was not used: HEASARC does not establish redistribution or commercial rights for Yale/author-owned data.

City data (`cities.js`): 108 cities (47 Japanese prefectural capitals, 61 major world cities). Coordinates are approximate city centres (degrees north/east, elevation 0 m), typed in by the app's author from general geographic knowledge and rounded to two decimals; they are plain facts and not copied from any database. Time zones are IANA names (https://www.iana.org/time-zones). Generated by `tools/ref/build-cities.mjs` (the list is inside that script). Accuracy is a few kilometres, enough for rise and set times within the app's tolerance.

## Faint stars (backdrop, 2026-11-15)

`faint-stars.js`: 730 Hipparcos entries with 3.1 <= V < 4.5 (the brighter 150 are in `stars.js`), columns HIP, RAICRS, DEICRS, Vmag, B-V, pmRA, pmDE from VizieR I/239/hip_main (`https://vizier.cfa.harvard.edu/viz-bin/asu-tsv?-source=I/239/hip_main&-out=HIP,RAICRS,DEICRS,Vmag,B-V,pmRA,pmDE&Vmag=3.1..4.5&-out.max=3000`), retrieved 2026-11-15 06:07 JST (2026-11-14T21:07:59Z). Epoch J1991.25 propagated to J2000 with the proper motions; the file keeps only RA, Dec, Vmag and B-V (rounded to 0.01) as a flat numeric array; no names or HIP numbers. Entries without B-V are stored as 0.6. Same terms as `stars.js`: ESA, CC BY-NC 3.0 IGO, Credit: ESA. Generator: `tools/build-faint-stars.mjs`.

## Constellation lines (round 2, 2026-11-15)

`constellations.js`: 14 figures (Orion, Orion's Belt, Canis Major, Winter Triangle, Summer Triangle, Big Dipper, Cassiopeia, Scorpius, Cygnus, Taurus, Pleiades, Great Square of Pegasus, Lyra, Aquila), 75 line segments. The lines were written by the programmer from star facts: each line is a pair of Hipparcos numbers (HIP) of stars that the traditional figure joins, chosen from the stars' own positions and brightness. No other software's constellation-line file was copied, consulted or imported, and no licensed line file is included. Figure names (Japanese and English) are common names transcribed by the programmer.

`constellation-stars.js`: the 28 line stars that are not in `stars.js` (V >= 3.1, or a few brighter ones that missed the 150-star cut), with the same Hipparcos columns as above (HIP, RAICRS, DEICRS, Vmag, pmRA, pmDE from VizieR I/239/hip_main, queried by HIP number), retrieved 2026-11-15 (see the header of the file for the exact time and URL). Epoch J1991.25 propagated to J2000. Same terms: ESA, CC BY-NC 3.0 IGO, Credit: ESA. Generator: `tools/build-constellation-stars.mjs`; the raw response is kept outside the app folder (`project/.tmp/2026-11-15/programmer/constellation-raw.tsv`).

## Moon map (round 9, 2026-11-15)

`public/assets/moon-map.jpg`: 3840×1920 equirectangular map of the Moon (greyscale JPEG, 912,701 bytes, SHA-256 `907975b0aa68eca61633860f6c9e0e76be195e689c969e025ad7a74006db5411`), made from the 3840×1920 PNG preview (SHA-256 `fcc9b65674c4e02293bf0205f6e566aee1bde608f63c3f340f446dda150286a8`, not downscaled) of the 27360×13680 "CGI Moon Kit - Lroc color poles.tif" with ffmpeg (format=gray, JPEG quality 3). Before round 10 it was a 2048×1024 colour downscale (451,802 bytes, SHA-256 `98e22fb7c1d60a328dda833664dd74b2c16439001a82fffa3b9b836db1db314d`). Page: https://commons.wikimedia.org/wiki/File:CGI_Moon_Kit_-_Lroc_color_poles.tif (licence field: Public domain); preview URL in `tools/assets/fetch-moon-map.mjs`; retrieved 2026-11-15 12:41 JST (03:41 UTC) and again 13:11 JST (04:11 UTC, same SHA-256). It replaces the 1024×512 `lroc_color_poles_1k.jpg` (139,068 bytes) used earlier. It is the same NASA SVS product as `lroc_color_poles_1k.jpg` from NASA's Scientific Visualization Studio, "CGI Moon Kit" (https://svs.gsfc.nasa.gov/4720), built from Lunar Reconnaissance Orbiter (LRO) data. The NASA server was unreachable from the dev container, so the identical file was fetched from its Wikimedia Commons copy: file page https://commons.wikimedia.org/wiki/File:Lroc_color_poles_1k.jpg (licence field: Public domain), URL https://upload.wikimedia.org/wikipedia/commons/7/7f/Lroc_color_poles_1k.jpg, retrieved 2026-11-15 12:19 JST (2026-11-15T03:19Z) with `tools/assets/fetch-moon-map.mjs`. Licence: NASA imagery is generally not subject to copyright restrictions (https://www.nasa.gov/nasa-brand-center/images-and-media/). Credit: NASA's Scientific Visualization Studio. The map is resized and re-encoded only. Longitude 0° is at the image centre, north is up.

`public/assets/mars-map.jpg`: 2048×1024 equirectangular colour map of Mars (JPEG, 372,633 bytes, SHA-256 `9c64680f6bf337d4ad3f8ede03c8160fa2ada48957309ff34f1d383dd48bd1cd`), made with ffmpeg (scale=2048:1024 area, JPEG quality 4) from "Mars Viking MDIM21 ClrMosaic 1km.jpg" (21339×10670, 36,708,552 bytes, SHA-256 `fdfcd335559c3dc67052b7e8a9565d850e336ac0d1f3ea7f5eb7826ffb44ecb2`), the 1 km/pixel reduction of the Viking Orbiter Colorized Mars Digital Image Model (MDIM 2.1, NASA/JPL/USGS; USGS Astrogeology "Mars_Viking_MDIM21_ClrMosaic_global_232m"). Page: https://commons.wikimedia.org/wiki/File:Mars_Viking_MDIM21_ClrMosaic_1km.jpg (licence field: Public domain; credit NASA / Jet Propulsion Lab / USGS); URL in `tools/assets/fetch-mars-map.mjs`; retrieved 2026-11-15 14:10 JST (05:10 UTC). Resized and re-encoded only; no shift was needed. Orientation (checked by eye on the image, features Olympus Mons, Valles Marineris, Hellas, Syrtis Major): longitude 0° is at the image centre, east longitude increases to the right, north is up. NASA and USGS do not endorse or sponsor this app. The mars sub-observer values in `closeupAt` follow the IAU 2009 rotation elements and are checked against JPL Horizons in `test/core/mars-view.test.mjs`.

`public/assets/jupiter-map.jpg`: 2048×1024 equirectangular colour map of Jupiter (JPEG, 178,464 bytes, SHA-256 `9079878d059a9b4b93e2f9f212025febf503945bb66df11d7a49d5f6f74a7b77`), made with ffmpeg from NASA/JPL/Space Science Institute **PIA07782** "Cassini's Best Maps of Jupiter (Cylindrical Map)" (Cassini narrow-angle camera, 11–12 Dec 2000; Wikimedia Commons "Jupiter Cylindrical Map - Dec 2000 PIA07782.jpg", 3601×1801, 441,285 B, SHA-256 of the original `6b835ddd8036ea9efd25def04f75aa60b69b096025a37eeae5e9b6978e0a2281`; licence {{PD-USGov-NASA}} = public domain; fetched 2026-11-15 with `tools/assets/fetch-jupiter-map.mjs`). Pixels are equal steps of planetocentric latitude and longitude (360°×180°). **Orientation (checked by eye): north up** (the Great Red Spot is in the lower half, about 22°S). The source does not state which longitude system or direction it uses; we assume the source's left edge = 0° with east increasing to the right, and **swapped the two halves so that 0° is at the image centre** (u = (east longitude + 180)/360, as for the Mars map). The source's poles are not covered: the top ~16 rows (north of about 88°N) and bottom ~80 rows (south of about 82°S) are the source's flat grey fill, left as is (not edge-extended). **Stripes, their tilt and the rotation direction/speed are real. Feature longitudes (Great Red Spot etc.) are cloud positions of Dec 2000 shifted by an arbitrary assumption, not a guide to where they are now.**