Historical clue formulations

• Shadow — 2026-04-09
• Darkest part of a shadow — 2022-06-22
• Shadow during an eclipse — 2020-12-06
• Shaded area — 2020-01-18
• Darkest part of a shadow — 2017-05-29
• Shadow — 2016-10-06
• Planetary shadow — 2010-12-26
• Shadow — 2009-10-22
• Planetary shadow — 2008-01-31
• Shadow — 2007-01-01
• Shadow — 2004-12-18
• Spectral image — 2004-10-31
• Dark area — 2004-07-18
• Shadow — 2003-10-31
• Shadow — 2002-09-25
• Planetary shadow — 2002-03-12
• Planetary shadow — 1999-11-21
• Dark area — 1997-02-09
• Eclipse feature — 1997-01-31
• Shadow — 1996-05-09
• Shade — 1995-09-07
• Eclipse shadow — 1994-07-05