APPLAUSE: flat before 1953 and flat after 1955, a step rather than a steady century fade
In APPLAUSE plates from 1915 to 1981 the star's differential magnitude is flat within each era: -0.10 ± 0.17 mag per century on the Lippert-Astrograph (1915-1956), and 5-year medians within ±0.05 mag from 1955 to 1980. Whatever change there is comes at a single time, not as a steady 0.16 mag per century. Enke et al. (2024), using APPLAUSE's global calibration, found no decade-scale variation at all.
Two archives (Harvard and APPLAUSE) now show the same shape, flat-step-flat, so the steady 0.16 mag per century model is the wrong description of whatever the plates record.For: Did the star fade over the twentieth century?
Ask Castelaz (Brevard College; APDA at PARI) for the per-plate magnitudes of the 835 Maria Mitchell plates, or the digitised cut-outs, and re-reduce them against the DASCH and APPLAUSE matched stars, testing for a 1950-1970 step.
2
Full per-plate differential with the Starglass platephot endpoint (needs a free API key): for each of the ~900 plates, pull every source within 10 arcmin and fit a plate zero-point from colour-matched stars within 5 arcmin of the target rather than 30 arcmin, then a hierarchical model with one zero-point per plate and one slope per star. Removes the position-dependent part of the plate systematics that the current 30-arcmin differential cannot.
Result. Suggestive support for a single drop. The step is the same sign as DASCH and larger, and lies beyond 95% of comparison stars in every comparison set and cut. It is not decisive: the honest error is ±0.10 mag, every change of era is also a change of telescope or emulsion, the within-telescope checks split, and per-system zero points erase it by construction. If real, the drop happened by about 1955..
Median differential after 1969 minus before 1953 (mag), ranked among comparison stars{'null': '0.012 ± 0.104', 'step': 0.154, 'frac_ge': 0.05, 'slope_null': '-0.02 ± 0.41', 'grid_step_range': [0.131, 0.178], 'system_mode_step': 0.037, 'slope_mag_century': 0.38}Suggestive support for a single drop. The step is the same sign as DASCH and larger, and lies beyond 95% of comparison stars in every comparison set and cut. It is not decisive: the honest error is ±0.10 mag, every change of era is also a change of telescope or emulsion, the within-telescope checks split, and per-system zero points erase it by construction. If real, the drop happened by about 1955.
Figure 1
On APPLAUSE plates the star sits about 0.15 mag fainter from 1955 on than in 1935-1950
KIC 8462852 minus matched and control comparison stars, 5-year medians (mag; positive = fainter); APPLAUSE DR4 Hamburg and Bamberg plates
5-yr median
Bins with at least 4 plates. Comparison stars show a step of 0.01 ± 0.10 mag. The change of era coincides with a change of telescope and emulsion, so the step cannot be separated from a calibration difference between systems.
Mysteries Department. (2026). APPLAUSE: flat before 1953 and flat after 1955, a step rather than a steady century fade [Evidence EVD0DFQ249YD49D]. https://mysteriesdept.com/r/EVD0DFQ249YD49D
@misc{mysteriesdept_evd0dfq249yd49d,
title = {APPLAUSE: flat before 1953 and flat after 1955, a step rather than a steady century fade},
author = {{Mysteries Department}},
year = {2026},
note = {Evidence, catalog key EVD0DFQ249YD49D},
url = {https://mysteriesdept.com/r/EVD0DFQ249YD49D}
}