# Planet imagery credits - 8 September 2026, cutouts 10 September 2026

These are downloaded NASA-hosted observations and observation-derived composites/maps, not AI-generated planet art. Files are converted to grayscale, and the colour discs graded to the homepage's levels, by `scripts/home-images/build-reading.sh` from the originals in git at `f6b8541a`. Prototype lighting, apparent rotation and scale are illustrative and do not depict current sky positions or live phases. NASA does not endorse Horospire or its interpretations.

## Globe textures

- `moon.jpg` - 2048 × 1024, 409,180 bytes. [NASA CGI Moon Kit](https://svs.gsfc.nasa.gov/4720/), NASA Scientific Visualization Studio / Ernie Wright; LRO Camera data collected by Arizona State University. [Original JPEG](https://svs.gsfc.nasa.gov/vis/a000000/a004700/a004720/lroc_color_2k.jpg). Natural-color LROC mosaic prepared for sphere mapping: exposure and white balance adjusted, missing data including high-latitude gaps filled by the NASA source. This is a processed global map, not a single photograph.
- `moon-1024.jpg` - 1024 × 512, 103,983 bytes, resampled from `moon.jpg` only (Lanczos, then grey); same source and credit. The far side of the masthead orrery's Moon (`orrery-moon.jpg`, below).
- `jupiter.jpg` - 1024 × 512, 78,709 bytes. [Hubble Maps Jupiter in 4k Ultra HD](https://svs.gsfc.nasa.gov/12021/), NASA Goddard Space Flight Center / Space Telescope Science Institute; science team Amy Simon, Michael Wong and Glenn Orton. [Original JPEG](https://svs.gsfc.nasa.gov/vis/a010000/a012000/a012021/Hubble_Jupiter_color_global_map_2015a_print.jpg). Hubble 2015 observation-derived cylindrical global map. Black strips at the upper and lower map edges represent unavailable polar coverage; they are not real black polar terrain. Atmospheric features are historical and change over time.
- `orrery-moon.jpg` - 1024 × 512, 117,274 bytes. The masthead orrery's Moon: `moon-1024.jpg` (LROC, above) with the hemisphere of the Apollo 11 frame AS11-44-6667 that the masthead's grey still shows (`mono/moon-disc`, below) laid in where the globe first faces the reader, divided by the orrery's light and feathered into the map at the limb, so the turning globe starts as the still. Made by `scripts/home-images/orrery-maps.py`; both credits apply (NASA SVS / LRO Camera, ASU; NASA / Apollo 11).
- `orrery-jupiter.jpg` - 1024 × 512, 73,455 bytes. The masthead orrery's Jupiter: `jupiter.jpg` (Hubble 2015, above) with the hemisphere of the Cassini globe that the masthead's grey still shows (`mono/jupiter-disc`, below) laid in the same way; the Hubble map's missing polar rows take the mean tone of its first and last full rows. Made by `scripts/home-images/orrery-maps.py`; both credits apply (NASA GSFC / STScI; NASA/JPL/University of Arizona).

## Chapter images

- `sun-disk.jpg` - **NASA/GSFC/SVS/SDO**. [Source record](https://images.nasa.gov/details/GSFC_20171208_Archive_e002069); [downloaded asset](https://images-assets.nasa.gov/image/GSFC_20171208_Archive_e002069/GSFC_20171208_Archive_e002069~small.jpg). SDO AIA full-disk view of launching filament. Extreme-ultraviolet 304 Å observations rendered in false color; not visible-light solar color.
- `moon-disk.jpg` - **NASA / Apollo 11**. [Source record](https://images.nasa.gov/details/as11-44-6667); [downloaded asset](https://images-assets.nasa.gov/image/as11-44-6667/as11-44-6667~small.jpg). AS11-44-6667, whole Moon photographed on the return journey, 21 July 1969. Historical full-disk photograph; not the current lunar phase.
- `mercury-disk.jpg` - **NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington**. [Source record](https://images.nasa.gov/details/PIA15162); [downloaded asset](https://science.nasa.gov/wp-content/uploads/2023/11/mercury-messenger-globe-pia15162.jpg?w=600). MESSENGER Mercury globe, PIA15162; spacecraft-image mosaic.
- `venus-disk.jpg` - **NASA/JPL-Caltech; processing Kevin M. Gill**. [Source record](https://www.jpl.nasa.gov/images/pia23791-venus-from-mariner-10/); [downloaded asset](https://science.nasa.gov/wp-content/uploads/2024/03/venus-mariner-10-pia23791-fig2-16x9-1.jpg?w=600). Mariner 10 PIA23791, 1974 data reprocessed in 2020. False-color orange/ultraviolet composite, with a synthesized green channel; cloud detail is enhanced.
- `mars-disk.jpg` - **NASA/USGS**. [Source record](https://images.nasa.gov/details/PIA04304); [downloaded asset](https://science.nasa.gov/wp-content/uploads/2024/03/mars-full-globe-16x9-1.jpg?w=600). NASA Science Mars full-globe image from Viking imagery; observation-derived mosaic.
- `jupiter-disk.jpg` - **Enhanced image by Kevin M. Gill (CC-BY), based on NASA/JPL-Caltech/SwRI/MSSS images**. [Source record](https://www.jpl.nasa.gov/images/pia22946-jupiter-marble/); [downloaded asset](https://science.nasa.gov/wp-content/uploads/2024/03/jupiter-marble-pia22946-16x9-1.jpg?w=600). Jupiter Marble PIA22946; color-enhanced composite of JunoCam images from 12 February 2019. Preserve the Kevin M. Gill attribution when displayed.
- `saturn-cutout.webp` - derived from `saturn-disk.jpg` on 9 September 2026 for the light theme, where a black frame cannot be keyed out with a blend mode: the black sky is made transparent (fully clear at a luminance of 8 and below, fully opaque from 34, the ramp applied only within three pixels of the sky) and the frame is cropped to the rings' bounding box, 372 × 165. The planet and rings are otherwise unaltered. Same credit as `saturn-disk.jpg` below.
- `saturn-disk.jpg` - **NASA/JPL-Caltech/Space Science Institute**. [Source record](https://images.nasa.gov/details/PIA21345); [downloaded asset](https://science.nasa.gov/wp-content/uploads/2023/05/saturn-farewell-pia21345-sse-banner-1920x640-1.jpg?w=600). Cassini PIA21345, So Far from Home, observations of 28 October 2016; RGB composite. Wide composition retains the rings.

## Display guidance

The disk images retain their original black backgrounds. Use CSS object positioning and dark backgrounds; do not stretch an image into a circle. Saturn needs a wider frame to preserve the rings. A photo can serve as the static fallback while the two global maps are used for genuine rotating sphere geometry. Every individual image is below 1 MB; maximum texture dimension is 2048 pixels. The combined nine JPEG assets are approximately 750 KB.

Recommended concise visible credit: “Planet imagery: NASA and mission partners. Jupiter photo: Kevin M. Gill (CC-BY), NASA/JPL-Caltech/SwRI/MSSS.” Link that credit to this source inventory. Use of imagery conveys no NASA endorsement.

## Cutouts (10 September 2026)

The files the reading ships are transparent WebP cutouts derived from the full-resolution versions of the frames listed above, downloaded again from the same NASA hosts on 10 September 2026 (the science.nasa.gov files without the `?w=600` size parameter, the images.nasa.gov `~orig` files, and for the Sun the SDO AIA 304 full-disk image of 10 September 2026 13:08 UT at 2048 px, https://sdo.gsfc.nasa.gov/assets/img/latest/latest_2048_0304.jpg, NASA/SDO, which replaces the 640 px GSFC archive frame). The derivation is a limb cut, not a retouch: each disc's limb is measured from the frame (an ellipse from the bright extent, Jupiter's oblate limb mapped onto a circle, the Moon's circle set three and a half percent inside the lit limb because the Apollo frame's terminator side is unlit), the disc is resampled into a square and given an anti-aliased alpha edge, and the pixels outside the limb take the limb's own colour so downscaling never blends the black sky into the edge. Saturn is keyed by luminance from the black sky with its rings intact; where the key is partial the colour is unmultiplied from black, and the faintest fringe takes the surrounding ring colour, so no dark halo survives on parchment.

- `sun-disc-360.webp`, `sun-disc-900.webp` from the SDO AIA 304 frame above (NASA/SDO).
- `moon-disc-360.webp`, `moon-disc-900.webp` from AS11-44-6667 at 1920 × 1930 (NASA / Apollo 11).
- `mercury-disc-360.webp`, `mercury-disc-900.webp` from PIA15162 at 2147 × 2147 (NASA/JHUAPL/Carnegie).
- `venus-disc-360.webp`, `venus-disc-900.webp` from PIA23791 fig. 2 at 1920 × 1080 (NASA/JPL-Caltech; processing Kevin M. Gill).
- `mars-disc-360.webp`, `mars-disc-900.webp` from PIA04304 at 1920 × 1080 (NASA/USGS).
- `jupiter-disc-360.webp`, `jupiter-disc-900.webp` from PIA22946 at 1920 × 1080 (Kevin M. Gill, CC-BY, from NASA/JPL-Caltech/SwRI/MSSS images). Converted to grayscale and graded by Horospire since 23 September 2026 (see the first paragraph); the attribution stands.
- `saturn-cutout-480.webp`, `saturn-cutout-1400.webp` from PIA21345 at 1920 × 640 (NASA/JPL-Caltech/Space Science Institute).

The 8 September `*-disk.jpg` frames and the 9 September `saturn-cutout.webp` are retired. The visible credit line is unchanged.

## Print copies (23 September 2026, the printed reading, E-01)

The PDF of the reading prints the same seven cutouts in one ink. mPDF applies no CSS filter and reads JPEG and PNG, not WebP, so the copies are made once by `scripts/home-images/grade-print-discs.py` and committed under `print/`. The grade is the homepage's (greyscale, the 1st percentile to 4 and the 99th to 215, gamma 1.1, a Lanczos downsample), measured on the opaque pixels of each cutout; nothing is painted, cloned or sharpened. Each disc is laid on the PDF's page ground, the parchment `#F4EEE0`, and saved as a JPEG. Saturn keeps the sky it was photographed against (the grade's black point) because its cutout's night side is transparent, so it prints as a small night plate with the brass edge.

- `print/sun-disc-280.jpg`, `print/sun-disc-640.jpg` from `sun-disc-900.webp` (NASA/SDO).
- `print/moon-disc-280.jpg` from `moon-disc-900.webp` (NASA / Apollo 11).
- `print/mercury-disc-280.jpg` from `mercury-disc-900.webp` (NASA/JHUAPL/Carnegie).
- `print/venus-disc-280.jpg` from `venus-disc-900.webp` (NASA/JPL-Caltech; processing Kevin M. Gill).
- `print/mars-disc-280.jpg` from `mars-disc-900.webp` (NASA/USGS).
- `print/jupiter-disc-280.jpg` from `jupiter-disc-900.webp` (Kevin M. Gill, CC-BY, from NASA/JPL-Caltech/SwRI/MSSS images). The greyscale conversion is a change to a CC-BY work and the PDF's credit says so ("converted to greyscale by Horospire").
- `print/saturn-plate-440.jpg` from `saturn-cutout-1400.webp` (NASA/JPL-Caltech/Space Science Institute).

The PDF's colophon prints every credit above and the sentence "NASA does not endorse Horospire."; the sample reading's file prints the Sun and Moon credits and the same sentence.

## Monochrome discs (23 September 2026)

The seven discs in the homepage's grade, shipped in `mono/` beside the released set, the top-level files of this folder, which are grey since 23 September 2026 (converted by `build-reading.sh`, see the first paragraph) and still render while the feature flag `reading_monochrome_discs` is off (audit I1; owner decision 5.9: monochrome discs, the generation colour kept as one lit mark in the page, never in the file). Every source is NASA and public domain: no ESA frame, no CC-BY frame, no SDO frame. NASA does not endorse Horospire or its interpretations.

The build is one command and reproducible: `bash scripts/home-images/build.sh discs` downloads the seven originals below into a cache outside the repository, checks their SHA-256 sums, and runs `scripts/home-images/cut-discs.py`, which rewrites every file in `mono/` and `mono/discs.json` (the measurements and the SHA-256 of every file it wrote). A second run on 23 September 2026 reproduced all 42 files byte for byte.

What was done to each frame, and nothing else:

- the limb is measured, not drawn: a circle fitted to the edge of the lit body by consensus (three edge points make a circle; the circle most edge points lie on within one percent of its radius wins, among circles that hold the whole body inside the frame), refined by least squares on its own points. The alpha is that circle, anti aliased. Jupiter's slight oblateness is left alone: the circle is fitted to the limb and nothing is stretched;
- the grade, shared with the homepage's plates and cairn: greyscale, the 1st percentile of the body to 4 and the 99th to 215, gamma 1.1 (output = input raised to 1/1.1), measured on the body because these frames are mostly black sky;
- the shadow key, on the two frames that are not fully lit inside their limb (the Moon, Venus) and only there: clear at 10 and under, opaque from 36 on the graded values, read from the frame smoothed over two percent of the radius, and applied only to shadow connected to the outside, so a mare or a crater stays what it is. Shadow pixels are unmultiplied from black (their grey is at least the key's opaque level), so the fade carries no dark rim onto parchment;
- Saturn: the same key over the whole frame on values smoothed over two pixels (the source is a heavily compressed JPEG), specks under half a percent of the body dropped, no hole closed;
- the pixels the alpha hides take the grey of the nearest body pixel, so no downscale can blend black sky into the edge;
- a square crop around the limb (Saturn: the silhouette's box), then a Lanczos downsample to 180, 360 and 900 px (Saturn 240, 480 and its own width). Nothing is upscaled: a body smaller than a rung ships the rung at its own width;
- AVIF monochrome (yuv400) with an alpha plane, and WebP with alpha, each down a quality ladder to a byte cap (14 KB at 180, 16 KB at 240, 40 KB at 360 and 480, 60 KB at 900, 70 KB at Saturn's large rung). The WebP of the large rung may run to 95 KB when no quality from 82 down to 40 fits 60 KB; that happened on the Moon and Mercury. Every browser that takes AVIF gets the AVIF, which fits.

No sharpening, no cloning, no painting, no rotation, no mirroring, no compositing. A cut and a grade, never a retouch.

**One cut serves both themes.** The homepage ships a night cut and a light cut where the night cut carries sky; these carry none, because the alpha is the limb. What is left near black is inside a body (a coronal hole, a crater shadow, a limb darkened by the atmosphere) and is photograph, not box. `cut-discs.py` measures it on every cut as `dark_share_pct` (the share of opaque pixels under 30): Sun 3.4, Moon 0.3, Mercury 1.8, Venus 0.0, Mars 3.3, Jupiter 7.0 (its limb darkening), Saturn 0.7. The chapter plate is a night plate in both themes (F-08, by design), so the question only arises in the wells of the locked rows, the strip, the gate and the masthead, where the disc sits in its own round well with a hairline rim on the cream card.


### The Sun, your own generation

- **NASA/JPL-Caltech/NRL/GSFC**, photographed by STEREO. Source record [PIA09320](https://images.nasa.gov/details/PIA09320), "Full Disk Image of the Sun, March 26, 2007".
- Downloaded file: <https://assets.science.nasa.gov/content/dam/science/psd/photojournal/pia/pia09/pia09320/PIA09320.tif>, 1920 x 1080 RGB, 6,229,676 bytes, SHA-256 `835a7b87dc76e7d5a554b00b4c4285a0f99b1c1b7a5ed2900b9b043c93a23334`. The Photojournal TIFF (lossless) of the record; the images.nasa.gov `~orig` JPEG is the same 1920 x 1080 frame compressed.
- What it is: A three wavelength extreme ultraviolet composite from the SECCHI EUVI imager, rendered in false colour by the mission and shown here in grey. It is not the Sun in visible light, and the credits say so. **This replaces the SDO frame**: STEREO is a NASA mission and its imager team is NASA Goddard and the US Naval Research Laboratory, so the frame carries NASA's public domain terms and none of the SDO site's "non-commercial" sentence (audit F-11). The corona glows green and white in this composite as brightly as the disc, so the body is found as the pixels where red leads green by 40 or more, and the limb is then refined to the steepest fall of brightness along 720 rays (`refine_limb`). The disc is 845 px from limb to limb, so the large file is 845 px wide: nothing is upscaled.
- Measured: limb centre (958.7, 541.6), radius 420.1 px, on 553 of 720 edge points; levels 70.0 and 174.0 to the shared 4 and 215; shadow keyed 0 px; cut 845 x 845.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `sun-disc-180.webp` | 180 x 180 | 8,652 | 82 | `193bd4e516f001018fe7e8d709e82d58dc297d25a42041688c9f9f214816a6ab` |
| `sun-disc-180.avif` | 180 x 180 | 7,420 | 60 | `937e8062d2fe2ad31f7a26a42bd3f231a242552125c3672ad9e938d9a32c8180` |
| `sun-disc-360.webp` | 360 x 360 | 20,890 | 82 | `555a32575dacc6133bb6eddd78272ce9cedffdc813c46e4fe67809856fee5f2c` |
| `sun-disc-360.avif` | 360 x 360 | 16,534 | 60 | `a600312cbd3442118211d0764d38035b48fe96284db894e5160539e3a0d0b3f0` |
| `sun-disc-845.webp` | 845 x 845 | 51,242 | 82 | `170efd847717bd5eddea6a43a3c47704d8696f1a28c0bbca5b562c1aa9c7b6c2` |
| `sun-disc-845.avif` | 845 x 845 | 40,927 | 60 | `9d800ea3ca913805c7dee7b566948f6ce6bb51ff9d49c8320159e4a2755ec84f` |

### The Moon, parents

- **NASA**, photographed by the crew of Apollo 11. Source record [AS11-44-6667](https://images.nasa.gov/details/as11-44-6667).
- Downloaded file: <https://images-assets.nasa.gov/image/as11-44-6667/as11-44-6667~orig.jpg>, 1920 x 1930 RGB, 2,250,538 bytes, SHA-256 `69629f78e3ccd939b39f31c19b89c1e2e751effd930d5a3a58f823403553f64c`. The same frame and the same file the released colour disc was cut from.
- What it is: The whole Moon from the return journey, 21 July 1969, a day past full, so its eastern limb is unlit. The fitted circle is the lit limb; the unlit edge inside it is keyed into the ground the disc stands on (the shadow key, below), which is why the Moon is the one disc whose outline is not a full circle. The homepage caption "Moon photograph: NASA, Apollo 11." stays true.
- Measured: limb centre (985.2, 854.8), radius 689.6 px, on 2878 of 5709 edge points; levels 5.0 and 241.0 to the shared 4 and 215; shadow keyed 27,128 px; cut 1384 x 1384.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `moon-disc-180.webp` | 180 x 180 | 7,570 | 82 | `b67c3b04fbdcb0454aaf278b99b6c3744f70a5bd6c89f720e0fa5f1b05a15f78` |
| `moon-disc-180.avif` | 180 x 180 | 6,698 | 60 | `68bc835be61a3c216009c8e3184e1eb2e2bdf2c51cb983707fbd2b3498928060` |
| `moon-disc-360.webp` | 360 x 360 | 26,100 | 82 | `8a04351f9ef51ee53d554d1ac948f5d12f55aee03d783155b3f7b4efc7da6689` |
| `moon-disc-360.avif` | 360 x 360 | 21,847 | 60 | `8bee1403400592f4a3d5b011e34b09a0f7c933bd2b314915bd2187b255382051` |
| `moon-disc-900.webp` | 900 x 900 | 90,776 | 64 | `0ab6e8f54f1f28c6072f2e35da76b2035b36a88a4a8c12601dd05e6ebd33fe05` |
| `moon-disc-900.avif` | 900 x 900 | 49,660 | 42 | `aae6171db129b2e9af708a0d6d952c94f7b9ae8b3c14eb07638d849c3a282205` |

### Mercury, grandparents

- **NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington**, MESSENGER. Source record [PIA15162](https://images.nasa.gov/details/PIA15162), "Mercury Globe: 0N, 180E".
- Downloaded file: <https://science.nasa.gov/wp-content/uploads/2023/11/mercury-messenger-globe-pia15162.jpg>, 2147 x 2147 L, 876,817 bytes, SHA-256 `5ea3d3b713fce74f6b45faa182023210ada11ae62b8b51183a5fc134e7ce1304`. The same file the released colour disc was cut from.
- What it is: A spacecraft image mosaic of the whole globe, already greyscale at the source; the grade only sets its levels to the family's.
- Measured: limb centre (1072.5, 1072.4), radius 975.4 px, on 5729 of 5729 edge points; levels 31.0 and 226.0 to the shared 4 and 215; shadow keyed 0 px; cut 1955 x 1955.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `mercury-disc-180.webp` | 180 x 180 | 8,690 | 82 | `ef87f572901d93eb8d2a890baa1235e926a1304b6929ddd2ba725b56888d569b` |
| `mercury-disc-180.avif` | 180 x 180 | 7,804 | 60 | `5d1afd3da84997e7e5cf2b58240723d20459ce02086b0f17bd752fb6e293ccfc` |
| `mercury-disc-360.webp` | 360 x 360 | 30,634 | 82 | `ce053fb7aec4d0e19744fca71de31ef021343cdb6d0d74a74b16189d1bf47301` |
| `mercury-disc-360.avif` | 360 x 360 | 26,996 | 60 | `721c15eb2d6b9d4f3a03b2aaf21a137e8f56de0fbbb793967b63b5ad23d47e71` |
| `mercury-disc-900.webp` | 900 x 900 | 93,024 | 40 | `db6f9737472efc1c3af0e563acf461a7db9776b1908b3b65a9a6291f48806989` |
| `mercury-disc-900.avif` | 900 x 900 | 57,871 | 34 | `02f0ccbcb3256e120ecab3a76cf4c421dc1d136db2584ba7331318eb5f136185` |

### Venus, great-grandparents

- **NASA/JPL-Caltech**, photographed by Mariner 10 in 1974, reprocessed in 2020 by Kevin M. Gill for JPL. Source record [PIA23791](https://www.jpl.nasa.gov/images/pia23791-venus-from-mariner-10/), figure 2.
- Downloaded file: <https://science.nasa.gov/wp-content/uploads/2024/03/venus-mariner-10-pia23791-fig2-16x9-1.jpg>, 1920 x 1080 RGB, 33,626 bytes, SHA-256 `5e8725e0714353ced875467983bf5ff606cb995e0d4756f383008b68042dd4c8`. The same file the released colour disc was cut from.
- What it is: A false colour composite of orange and ultraviolet frames, shown here in grey. The record's credit is NASA/JPL-Caltech, a JPL release under NASA's terms; the processing credit is kept here out of courtesy, not as a licence term. Venus is lit from the left in this frame, so its right limb is keyed like the Moon's.
- Measured: limb centre (972.5, 540.4), radius 460.0 px, on 1294 of 2522 edge points; levels 0.0 and 245.0 to the shared 4 and 215; shadow keyed 66,507 px; cut 925 x 925.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `venus-disc-180.webp` | 180 x 180 | 4,544 | 82 | `db5b98480a4aa009984c8151af8b3ef723ecce830ff3530bd990e8c280dab788` |
| `venus-disc-180.avif` | 180 x 180 | 2,773 | 60 | `48646a67eda697689ee143f110c922b1cfe75ecc1e63b4acdd45005a808b59f5` |
| `venus-disc-360.webp` | 360 x 360 | 10,124 | 82 | `8a920ade122105c93ab28929cf403a35adaae06da8f6216412949351acdf63f2` |
| `venus-disc-360.avif` | 360 x 360 | 5,158 | 60 | `2b4a161a90b63b1bfdda23b8ff20591395fce61c50dd19d387cdf82aa3095d92` |
| `venus-disc-900.webp` | 900 x 900 | 30,898 | 82 | `8d4306630b54f6019e1b4ca3ab9778ef22dd19a2d055321ff20cf027f25f8d17` |
| `venus-disc-900.avif` | 900 x 900 | 14,132 | 60 | `bf6196f6eb1274a746d94179873d786e97c61fe5582bea8571f885c6cb3f1f1e` |

### Mars, fifth generation

- **NASA/USGS**, Viking Orbiter. Source record [PIA04304](https://images.nasa.gov/details/PIA04304).
- Downloaded file: <https://science.nasa.gov/wp-content/uploads/2024/03/mars-full-globe-16x9-1.jpg>, 1920 x 1080 RGB, 66,143 bytes, SHA-256 `07044220120a329ceec28a04e81ded8d569edf09389cbf14956e0c651b646b88`. The same file the released colour disc was cut from.
- What it is: A mosaic of Viking Orbiter frames with Valles Marineris across the face; a colour mosaic shown in grey.
- Measured: limb centre (966.8, 532.0), radius 484.6 px, on 1649 of 3771 edge points; levels 22.0 and 202.0 to the shared 4 and 215; shadow keyed 0 px; cut 974 x 974.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `mars-disc-180.webp` | 180 x 180 | 5,676 | 82 | `b1fb1d0b79efaac421ba6beb82d739182476e1f50b22dffb8a291ecdcd096a5d` |
| `mars-disc-180.avif` | 180 x 180 | 4,488 | 60 | `5c7eedecd32052f3f15707f84befe81cea5bc0ca6d22f54e1754997543365f12` |
| `mars-disc-360.webp` | 360 x 360 | 15,830 | 82 | `c75e83ceb8d9676c5a62760c2a56ef6a52b8551211be24b3643ae6dd3f7bfe16` |
| `mars-disc-360.avif` | 360 x 360 | 11,726 | 60 | `d6bf0285987a26e9b74a0b33b4cc13d1a54f3c061f370a1e78d893fb73a63745` |
| `mars-disc-900.webp` | 900 x 900 | 49,744 | 76 | `95853112dd8aef8dd77efe748cf85125e93043efcaee3c38bf382e6c5fdbd3c1` |
| `mars-disc-900.avif` | 900 x 900 | 46,541 | 60 | `10816f4a06eee75e5d3ead067d78bd1db7743b43eb37fc521b5deb8d678803de` |

### Jupiter, sixth generation

- **NASA/JPL/University of Arizona**, Cassini. Source record [PIA02873](https://images.nasa.gov/details/PIA02873), "High Resolution Globe of Jupiter".
- Downloaded file: <https://assets.science.nasa.gov/content/dam/science/psd/photojournal/pia/pia02/pia02873/PIA02873.tif>, 1920 x 1080 RGB, 2,378,772 bytes, SHA-256 `d068de5b9bae577f171b5ba59a0058b57bb3e7b5491c591b93cb3983130aa746`. The Photojournal TIFF (lossless) of the record.
- What it is: Four Cassini narrow angle frames of 7 December 2000, a true colour cylindrical map **projected onto a globe** by the Cassini imaging team; Europa's shadow is on the clouds. **This replaces Kevin M. Gill's CC-BY Jupiter Marble (PIA22946)**, so no frame in the monochrome set carries a licence beyond NASA's. The Cassini Jupiter Portrait (PIA04866, a true photograph mosaic) was measured and rejected: a third of its disc is in shadow, which on parchment is a black crescent. Voyager 2's PIA01369 is a close view of the clouds, not a disc.
- Measured: limb centre (1003.5, 545.6), radius 489.4 px, on 2210 of 3019 edge points; levels 41.0 and 204.0 to the shared 4 and 215; shadow keyed 0 px; cut 983 x 983.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `jupiter-disc-180.webp` | 180 x 180 | 5,388 | 82 | `219322136fe420d762b29ee47e223bc00343899721c800a8193d852a0537650d` |
| `jupiter-disc-180.avif` | 180 x 180 | 3,967 | 60 | `a982368f767591f8d8ac47e54c6a3ed3168bccedace52ab04a75b460dffac9a8` |
| `jupiter-disc-360.webp` | 360 x 360 | 12,840 | 82 | `9c8ef746c3d69c58cf9a188fb6b9bb9431ccd73f44c7026d64ae0c3f7f73ec19` |
| `jupiter-disc-360.avif` | 360 x 360 | 8,465 | 60 | `5a61ae0d94b74a5c77641061e8bc244813c47fdfc8917568be57cbb92cef2506` |
| `jupiter-disc-900.webp` | 900 x 900 | 39,060 | 82 | `849b9ae8398b1b1b55cb8ff7778dc5567cd76b1e6389c72b10a1b057b8834f40` |
| `jupiter-disc-900.avif` | 900 x 900 | 21,850 | 60 | `b03488e3cc6f56dd173470199d6325ae5b8a0343d6f11631ab7f265d986fd9cc` |

### Saturn, seventh generation

- **NASA/JPL-Caltech/Space Science Institute**, Cassini. Source record [PIA21345](https://images.nasa.gov/details/PIA21345), "So Far from Home".
- Downloaded file: <https://science.nasa.gov/wp-content/uploads/2023/05/saturn-farewell-pia21345-sse-banner-1920x640-1.jpg>, 1920 x 640 RGB, 33,723 bytes, SHA-256 `a6eaba8a172b65ae9bf96cfa941cd0077b7abe1a3c63fee8974c74e8df06f20f`. The same file the released colour cutout was cut from.
- What it is: Cassini's look back at Saturn and its main rings, 28 October 2016. Keyed by luminance with the rings intact and no hole closed, so the gaps in the rings and the planet's shadow on them stay open. The rings are 1134 px wide at the source, so the large file is 1134 px: the released 1400 px cutout had been upscaled from this frame, and this one is not.
- Measured: levels 40.0 and 235.0 to the shared 4 and 215; crop box (477, 68, 1611, 565); cut 1134 x 497.

| File | Size | Bytes | Quality | SHA-256 |
|---|---|---|---|---|
| `saturn-cutout-240.webp` | 240 x 105 | 10,140 | 82 | `a5290f7ebdafaad39f8938dc8aa906e3affb3059a793e73b3043badbedc459e8` |
| `saturn-cutout-240.avif` | 240 x 105 | 6,199 | 60 | `510902577dd372c6c161181c90612445fbebb865f81c53e9ce44e6ffa9affca9` |
| `saturn-cutout-480.webp` | 480 x 210 | 27,128 | 82 | `55e84b09a44ca66d6b541191a7631434fe533fd96da718c5fd9df0f07036d51e` |
| `saturn-cutout-480.avif` | 480 x 210 | 13,662 | 60 | `56b646f9fb4a6cfab9fd4d78eceea6e5f54abb7f9f32a58d8979d940d6e6a718` |
| `saturn-cutout-1134.webp` | 1134 x 497 | 68,956 | 82 | `c1fac4d54a58724ed32d155f0d156d0f516e1b279eee7f51360ecf76a281c415` |
| `saturn-cutout-1134.avif` | 1134 x 497 | 33,501 | 60 | `a7c08aea69be9dbde67421cebb2b7bf9a81156bf416e2429dd3e17782072f13f` |

All 42 files: 1,026,125 bytes. The released set in this folder, grey since 23 September 2026, is 1,069,668 bytes of WebP, one format, two sizes.

### Frames downloaded, measured and not used

Recorded so the choice can be checked; none ships.

- SDO AIA 304, [GSFC_20171208_Archive_e002069](https://images.nasa.gov/details/GSFC_20171208_Archive_e002069), `~orig` 1280 x 720, SHA-256 `e13524641873a6ec38798932ff3823f2f9fa33e27caf6c309d0f0fbe3eb4af34`: SDO, the frame the reading's first Sun came from. Not used, because an SDO free NASA frame exists (above). The released set's own Sun (`sun-disc-*.webp`, from `latest_2048_0304.jpg` of 10 September 2026, grey since 23 September) remains an SDO frame under SDO's "non-commercial" sentence while the flag is off; that URL is a rolling "latest" image and cannot be re-downloaded to the same bytes.
- Skylab, [7461522](https://images.nasa.gov/details/7461522), 3000 x 2340, SHA-256 `273f5a4ce9d16b9c212960e25350fce6e16a19d01ef9c178f9c2d975a08e920f`: a false colour close view of a prominence, not a disc.
- Skylab, [9606705](https://images.nasa.gov/details/9606705), 3000 x 2303, SHA-256 `4c5d0fdb2cd3d14eb7b720de7b2893637efe4566e697694f8a5a5a10789c5bf4`: the disc composited over a coronagraph field and cut by the frame edge; no clean limb.
- PIA09320 as the images.nasa.gov `~orig` JPEG, 1920 x 1080, SHA-256 `6480376b8a721d9c2b6a86d1be697585d6ad8d3e2d4d503c04c7b5af5fcfab1d`, and PIA02873 likewise, SHA-256 `2b754a3a2566400da1bb268e98d087dd42a4b04bfe9374db090886d8e959f133`: the same frames as the TIFFs used, compressed.
- Cassini Jupiter Portrait, [PIA04866](https://images.nasa.gov/details/PIA04866), `~orig` 1920 x 2400, SHA-256 `c60ac9393e4810fb12a122bbefbf52f5b5f9aaa60450991cdd3c5a85385b14f0`: a third of the disc in shadow.
- Voyager 2, [PIA01369](https://images.nasa.gov/details/PIA01369), 916 x 901, SHA-256 `9d3ec27e313cf574f8079e495bfe235106dd9ab0b2dbf3b7a35e95a42eec2abd`: a close view of the clouds, not a disc.

### Visible credit

With the flag on, one line wherever the discs print (the reading's footer, the reveal gate), linked here: "Planet photographs: NASA and mission teams (STEREO, Apollo 11, MESSENGER, Mariner 10, Viking, Cassini), shown in grey. NASA does not endorse Horospire." With it off, the released line gains the endorsement sentence and keeps the CC-BY attribution, now on the gate as well; the released Jupiter it credits is Kevin M. Gill's frame converted to grey, and this file, which the line links, says so (the first paragraph and Cutouts): "Planet imagery: NASA and mission teams. Jupiter photograph: Kevin M. Gill (CC-BY), NASA/JPL-Caltech/SwRI/MSSS. NASA does not endorse Horospire." `/sample-reading`, either way: "Moon photograph: NASA, Apollo 11. NASA does not endorse Horospire." `ReadingImageCreditsTest` pins all three.