Historical clue formulations

• ___ Scotia — 2026-09-08
• White dwarf phenomenon — 2026-06-21
• Milky Way explosion — 2026-06-11
• Luminous stellar explosion — 2026-05-25
• Cold-smoked lox — 2026-05-16
• Flare up? — 2025-11-30
• Cosmic explosion — 2025-08-03
• Cosmic explosion — 2025-03-22
• ___ Scotia — 2025-02-18
• Brilliant observation? — 2024-12-01
• Smoked salmon — 2024-07-22
• Neon sign outside a motel — 2024-07-18
• PBS science series since 1974 — 2023-06-26
• Exploding star — 2023-06-06
• Award-winning PBS docuseries — 2023-05-05
• Stellar phenomenon — 2022-07-14
• Flare up? — 2022-03-23
• Astronomical news — 2022-03-17
• Astronomical event — 2021-11-30
• PBS science show since 1974 — 2021-05-10
• Observation from an observatory — 2021-04-02
• Emmy-winning science series — 2021-02-17
• Sighting in a telescope — 2020-11-12
• Exploding star — 2020-10-18
• Starburst? — 2020-05-16
• Massive explosion — 2020-05-01
• Celestial explosion — 2019-12-16
• Flare way up? — 2019-09-21
• The first recorded one was noted by the Greek scientist Hipparchus in 134 B.C. — 2019-06-09
• PBS series since 1974 — 2019-03-07
• ___ Scotia — 2019-02-25
• ___ Scotia — 2018-11-12
• Salmon variety — 2018-07-12
• ___ Scotia — 2018-07-10
• Smoked salmon — 2018-02-20
• Astronomical event — 2018-01-28
• Salmon at a deli — 2018-01-17
• Blast from the past, astronomically speaking? — 2017-12-28
• Burst in space — 2017-12-20
• Bygone Chevy model — 2017-09-15
• Terra ___ (old name for Newfoundland) — 2017-06-14
• Astronomer's sighting — 2017-05-07
• Massive explosion — 2015-11-27
• Deli purchase — 2015-09-23
• Deli item that's 14-Across backward — 2015-08-21
• Bagel topper — 2015-05-31
• Exploding star — 2015-02-23
• Star burst — 2014-06-01
• Stellar phenomenon — 2014-01-07
• Brilliant 13-Down — 2013-12-04