July 25
The Forgotten Thirteenth
Sun Position
The Sun is in Leo at about +19.5° declination. Northern Hemisphere summer; Southern Hemisphere winter. Ophiuchus reaches the meridian around midnight, well-placed for both hemispheres.
Sky Highlight
The Southern Delta Aquariids are approaching their peak. On July 25, rates from a dark southern site may be 10–15 meteors per hour; northern observers will see fewer due to the low radiant. No other major annual event falls on this date.
Deep Sky Object
M14 (NGC 6402), a globular cluster in Ophiuchus roughly 30,000 light-years away. It is a large, slightly elliptical cluster; a nova was observed within it in 1938, confirmed years later when examining archival photographic plates. Accessible from both hemispheres given Ophiuchus's near-equatorial position.
Featured Star
Rasalhague (α Oph) is a white giant 47 light-years away in Ophiuchus, classified A5III. The Sun passes through Ophiuchus each November and spends more time there (19 days) than in neighboring Scorpius (6 days), but because the modern zodiac was fixed before the ecliptic shifted, Ophiuchus has never been assigned a zodiac sign, its status as an unofficial thirteenth house is a genuine astronomical fact, not mythology.
Around This Date
- July 25, 1984Soviet cosmonaut Svetlana Savitskaya became the first woman to perform a spacewalk, conducting welding and cutting experiments outside the Salyut 7 space station.
- July 25, 1992Space Shuttle Columbia launched on STS-50, the first mission to carry Extended Duration Orbiter hardware, allowing the crew to remain in orbit for nearly 14 days while conducting microgravity experiments.
Rasalhague marks the head of a figure the sky counts but the calendar ignores, a boundary dispute thirty centuries in the making.