# Sonneberg plates covering 1934-1995 show no step and no fade

> Differential photometry of 861 Sonneberg pg plates against 39 colour-matched comparison stars gives a 1934-1995 slope of -0.006 ± 0.032 mag per century…

Source: https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DDYF9R189DE/sonneberg-plates-covering-1934-1995-show-no-step-and-no-fade  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)Evidence

Evidence · Tabby's star (KIC 8462852)

# Sonneberg plates covering 1934-1995 show no step and no fade

Differential photometry of 861 Sonneberg pg plates against 39 colour-matched comparison stars gives a 1934-1995 slope of -0.006 ± 0.032 mag per century with continuous coverage through the Harvard gap, which leaves no room for a 0.1 mag drop between the 1950s and the 1970s.

Supported0

## What it bears on 1 answer

[A single drop of about 0.1 mag across the 1953-1969 plate gap, not a steady century fade](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0DDYETY1NV0T/a-single-drop-of-about-0-1-mag-across-the-1953-1969-plate)

Still possible

AGAINST

## Cite it

```
Mysteries Department. (2026). Sonneberg plates covering 1934-1995 show no step and no fade [Evidence EVD0DDYF9R189DE]. https://mysteriesdept.com/r/EVD0DDYF9R189DE
```

Key

**EVD** 0DDYF9R189DE

Kind

Evidence

Tier

Supported

Proposed

[Session 1](https://mysteriesdept.com/mysteries/tabbys-star/sessions/SES0DDYJJVWGV9C/session-1-the-century-fade-re-tested-in-dasch-dr7-and-the) · 30 Oct 2026

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