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.
The apparent 28 September 1917 inscription includes 17 exposures, a 60-second setting and a 12-inch aperture. Comparison with R3662 may reveal a controlled change, but exposure time, aperture and emulsion response are confounded until the notes are verified. No celestial WCS or physical response calibration is claimed.
Photographic points and streaks are organized into columns. Similarity to R3662 is a visual observation, not proof of identical targets, settings or exposure times.
The margin appears to say “Polaris Calibration”, “1917 Sept. 28”, “17 exp.”, durations including “60 s”, and “12” aperture”. This supports comparison with R3662 while suggesting a setting change. The written aperture and exact pairing remain unverified historical readings.
The revised layer uses local contrast in both polarities, expanded inspected writing regions and contextual recovery of short fragments and round digits. Known photographic targets and sampled spectral apertures are protected. It is not OCR and does not reconstruct hidden sky or invent pen strokes.
The selection covers 3.51% of this scan (735,067 pixels). Faint marks, scratches and contacts between ink and photographic images remain ambiguous. The cyan overlay shows the wider exclusion footprint used by the photographic remainder; the stroke mask is supplied separately.
The writing PNG is a white, contrast-rendered stencil of bright and dark observed marks. The observed-pixel PNG preserves their stretched scan appearance. Both use original scan coordinates. The photographic remainder displays excluded pixels as black holes. It is neither a clean-sky reconstruction nor a new photometric product. Keep the mask alongside any measurements. Native original-intensity TIFF/FITS products, where generated, remain in the analysis workspace and are not duplicated in this handoff.
This revision recovers short letter fragments, round digits and inspected dark marks, with broader writing regions. The stroke selection grows from 381,277 to 735,067 pixels (1.93×). The photographic remainder uses a separate 3-pixel exclusion margin, covering 7.53% of the scan.
The wider selection deliberately favors removing writing. Nearby stars, scratches and ambiguous fragments can also be excluded. Explicit photographic protection regions retain known target images and sampled spectra; this does not establish perfect separation elsewhere.
There is no confirmed celestial solution and no field center is assigned. Repeated experimental targets cannot substitute for independent catalog stars.
The apparent 28 September 1917 inscription includes 17 exposures, a 60-second setting and a 12-inch aperture. Comparison with R3662 may reveal a controlled change, but exposure time, aperture and emulsion response are confounded until the notes are verified. No celestial WCS or physical response calibration is claimed.
Across these scans, repeated photographic images need not imply the same mechanism. Shutter timing, guiding offsets, objective optics and different pointings can leave related patterns. Establish consistent component membership before fitting a smooth warp. No result here isolates glass deformation from telescope optics, emulsion, scanner geometry and centroid bias.
A response or focus comparison would require verified settings, unsaturated original pixels and consistent background treatment. The display JPEG is contrast-stretched for inspection and cannot be used to compare absolute photographic density between plates.
The native writing PNG and mask are the current derived products. They are candidate selections of observed strokes; there is no WCS, glass correction or photometric linearization.
Select a numbered pin or a note. Locations are editorial review pointers, not measured confidence contours; plate-wide limitations also apply.
The target and ordering of controlled conditions remain unknown.
Pen numbers near extended photographic images are difficult to separate where their signals overlap.
The relation to R3662 should be established from records rather than filename adjacency.
Establish the written schedule and any pairing with R3662, then compare matched profile widths and integrated signals on the original 16-bit images.
The report preserves a plausible comparison experiment and its written context, while leaving physical calibration and historical identity open.
All scientific numbers are snapshots of the saved analysis products. The original 16-bit scans remain the measurement source. JPEG derivatives, contrast stretching and masked previews are inspection tools; do not derive photographic density or absolute response from their appearance.
