Glass, sky
& written traces.
Fourteen photographic plates, inspected individually. A visual record of recovered fields, extracted writing, measured distortions and the questions the scans cannot yet answer.
The collaborator edition adds exposure-aware reassessment, the UV1693 solve, two secondary sky fields, corrected A–B–A extraction and provisional Balmer-reference spectra. Open a plate for its full report. Every page, image, font and interaction is local. The original TIFFs are kept separately.
A wide Cygnus field, recovered beneath the ink.
Cygnus and a second Kap 41 field are independently recovered on the same glass. The tested cubic correction belongs to the original Cygnus component; the written Pole pointing remains unconfirmed.
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A secure northern field; extra curvature is not yet justified.
A rich photographic star field solves cleanly. Independent fit checks favor the simpler tangent-plane model over the tested polynomial corrections.
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A written field hint rescues a repeated-exposure plate.
The first apparently significant all-sky candidate was wrong. Reading the margin and grouping repeated photographic images leads to a strongly supported field near Selected Area 20.
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Two distinct sky fields on one narrow-field plate.
The original southern field and a second ζ Cancri pointing are both recovered. Sparse independent checks still limit distortion claims.
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The sky is identified; distortion validation remains open.
Grouping repeated exposures produces a strong field identification. Too few unused reference associations remain for a trustworthy independent distortion fit.
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A polar field recovered from repeated stellar triples.
The retry succeeds: selecting one real exposure member reveals the northern polar field. A blind solve is independently supported by 530 additional catalog matches.
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A repeated target sequence, with too little independent sky.
The visible structure is dominated by a sparse photographic ladder and extensive writing. A useful next analysis is exposure morphology and historical metadata rather than a speculative sky warp.
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Two structured photographic targets, not yet a sky field.
Two small rosette-like images and their labels are the main evidence. They are protected from the annotation mask, but their physical interpretation and celestial identity remain unknown.
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Three spectra, correctly separated as A–B–A.
The corrected extraction follows three non-crossing records through the bright lower feature. The outer patterns agree closely; the middle spectrum is different.
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A graded spectral grid, with its line structure recovered.
Repeated spectral records yield numerical profiles, and five central-row tracks now support a provisional Balmer-reference wavelength scale with unused-line checks.
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A second spectral grid for an eventual calibrated comparison.
Repeated spectral records yield numerical profiles, and five central-row tracks now support a provisional Balmer-reference wavelength scale with unused-line checks.
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Photographic comparison columns among written numbers.
A compact sequence of point-like and streak-like images appears to be an exposure comparison. The spatial arrangement is useful, but a celestial coordinate model is not justified.
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A companion exposure sequence with its own open metadata.
This plate resembles R3662 in its column-like photographic sequence and handwritten context. The relationship is worth investigating, but has not yet been established quantitatively.
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Five broad photographic disks within an illuminated field.
The dominant structure resembles a repeated focus or exposure test. The broad disks are photographic content and are deliberately excluded from the written annotation selection.
Read the laboratory report ↗Read the evidence at its own strength.
“Calibrated field” means the coordinate fit was tested using held-out stars. It does not mean a physical glass distortion was isolated. R4011 retains TAN; UV1642 retains cubic SIP; R4073 retains cubic SIP with an explicitly worse residual tail.
The two pi plates have supported primary field identifications but limited or absent distortion validation. The additional ζ Cancri component has only four extra check stars and fails the stricter eight-star gate. Six other plates look like spectral or exposure-calibration records. UV1693 is now identified from a consistent repeated-image component; UV1753 and UV1901 remain unresolved as sky fields.
Annotation PNGs select observed marks. They can miss faint strokes and cannot recover astronomical signal hidden under ink. A masked photographic preview leaves holes rather than inventing their contents.
Collaborator edition · what changed.
UV1693 is solved near the north celestial pole. UV1642 and pi4146–47 each contain a second recovered sky field. R4073 strongly supports a long-plus-short double exposure. IB5894 now has three correctly separated A–B–A profiles; ten OP profiles have provisional Balmer-reference scales. The Castor comparison now includes proper motion and the historical attenuation hypothesis.
These findings revise how the plates should be measured. A WCS registers a particular sky/exposure component, not every image on the glass. Empirical distortion remains distinct from physical glass deformation. Spectral line references remain distinct from an independent redshift measurement.
| Plate | Current evidence and remaining limit |
|---|---|
| UV1642 | Two independently recovered sky fields; a third written pointing remains open. |
| R4011 | A strong field solution with no established extra exposure component. |
| R4073 | Strong evidence for two unequal photographic exposures. |
| pi4146-47 | Two sky pointings occupy the same scan. |
| pi4197-98 | Castor is identified; another offset family remains unexplained. |
| UV1693 | Solved after retaining one consistent member of repeated triples. |
| UV1753 | Repeated target images favor a focus experiment; no field solution. |
| UV1901 | Two structured photographic targets; no validated sky WCS. |
| UV960 | Broad target disks; their physical meaning remains open. |
| R3662 | A written Polaris calibration sequence, not a solved field. |
| R3663 | A second Polaris calibration sequence with different written settings. |
| IB5894 | Three separate records: A–B–A, including the formerly clipped end. |
| OP966 | Repeated spectra, with five provisional Balmer-reference scales. |
| OP967 | A companion spectral plate, with five provisional Balmer-reference scales. |