Author Archives: Roger W. Sinnott

New Comet Machholz

California's comet-hunting veteran Don Machholz bagged his 11th discovery on March 23 and 26, 2010. It's a faint diffuse comet, low in the morning sky.

John Gregory shows off an exotic 8-inch doublet lens he designed and made in 1987. It featured better image correction than many triplet objectives.

In Memoriam: John Gregory

The world of amateur telescope making has lost a charismatic optical engineer and innovator at age 82. One of the "big guns" of yesteryear, John Gregory introduced the Gregory-Maksutov telescope design, giving basement mirror makers a high-end alternative to, well, just mirrors.

On April 6, 2009, a trio of Italian observers captured Comet Yi-SWAN with a 10-inch reflector operated by Global-Rent-A-Scope near Mayhill, New Mexico. This is a stack of 10 exposures of 60 seconds each.

Five Amateurs Win Comet Prize

The 2009 Edgar Wilson Award honors amateur astronomers who discovered five different comets in the last 12 months, proving that backyard comet hunting still thrives in this age of automated professional sky patrols.

The July 22, 2009, total eclipse of the Sun was a late-afternoon spectacle for the Ring of Fire Expedition to the islet of Ouba, at latitude 2° north in Kiribati.

Eclipse Over a Pacific Isle

The coral-ringed islet of Ouba in Kiribati (the Gilbert Islands) is less than a kilometer in circumference and about the remotest corner of Earth from which one could witness the total solar eclipse on July 22, 2009. A select group from Ring of Fire Expeditions did just that.

Texas researchers have resolved longstanding disputes over when in 55 BC and where Caesar first came ashore on the southern coast of England. For a wider version of this map, click here.

Astronomers Re-Date Caesar’s Invasion of Britain

FOR IMMEDIATE RELEASE Contacts: Donald W. Olson, Department of Physics, Texas State University     512-245-2131, dolson@txstate.edu Roger W. Sinnott, Senior Editor, Sky & Telescope     617-864-7360 x2146, rsinnott@SkyandTelescope.com Cambridge, MA, June 30, 2008 — Researchers from Texas State University have revised the date when Julius Caesar invaded Britain in 55 BC, a transformational event in world...

Caesar's fleet arrived first at the white cliffs of Dover on the southeastern coast of Britain, but he decided this was not a suitable landing spot.

New Date for Caesar’s British Invasion

In 55 BC, when Julius Caesar and his fleet approached the white cliffs of Dover on the British coast, he faced unexpectedly strong tides. Researchers from Texas State University have used tidal measurements and other astronomical clues to revise the exact date of the historic landing.