July 28
The Preceding One
Sun Position
The Sun is in Leo at about +18.4° declination. Northern Hemisphere summer days continue shortening slowly; Southern Hemisphere winter nights remain long and excellent for observing.
Sky Highlight
The Southern Delta Aquariids are at or very near their annual peak around July 28–30. From a dark southern site with the radiant well up, 20 or more meteors per hour is typical. The shower is active into August, so observers who miss the peak get multiple opportunities. Northern Hemisphere observers see the radiant low, limiting rates to 5 or fewer per hour.
Deep Sky Object
NGC 6369, the Little Ghost Nebula in Ophiuchus, roughly 2,000 light-years away. A nearly circular planetary nebula with a faint central star, it is a smaller and less famous relative of the Ring Nebula. Requires a medium telescope under dark skies to see clearly. Accessible from both hemispheres given Ophiuchus's equatorial location.
Featured Star
Sabik (η Oph) is a binary system 88 light-years away in Ophiuchus, two nearly matched white main-sequence stars, A2V and A3V, orbiting with a period of roughly 88 years. Orbital solutions suggest the pair will become easier to split in a telescope as their apparent separation increases over the coming decades. The name may mean 'the preceding one,' though its precise origin remains debated.
Around This Date
- July 28, 1851Johann Julius Friedrich Berkowski made the first successful photograph of a total solar eclipse at Königsberg, capturing the solar corona on a daguerreotype during totality and opening the era of solar photography.
- July 28, 1955President Eisenhower and the National Security Council received a full classified briefing on the Atlas ICBM program from General Bernard Schriever and John von Neumann, the missile that would later launch the first American orbital missions.
Two near-identical stars orbiting each other for 88 years. Sabik is as close to a matched set as the sky offers.