Skylights featured on Astronomy Picture of the Day

Scout Report Selection Webivore Selection SpaceCareers Selection

Skylights featured nine times on Earth Science Picture of the Day: 1 2 3 4 5 6 7 8 9 -- Full List Restored!


Photo of the Week. Look what's coming!

Astronomy news for the two weeks starting Friday, July 3, 2015.

The next skylights will appear July 17, 2015. Happy Independence Day. And Bastille Day too.

We begin as usual with the Moon, which starts our fortnight in its waning gibbous phase as it heads toward third quarter on Wednesday, July 8. It then takes a week to go through waning crescent, which ends at new Moon on Wednesday the 15th. The morning of Saturday the 11th finds the Moon to the right of the Pleiades of Taurus. By the following morning, the crescent will lie at the western edge of the Hyades cluster with Aldebaran down and to the left, the Pleiades now on top. Your last look at the thin rising crescent will be morning of Tuesday the 14th. With a good horizon you then might spot the waxing crescent in the west the twilit evening of Friday the 17th, Jupiter and Venus shining up and to the left. (Reserve the evening of Saturday the 18th for a spectacular gathering of the crescent Moon, Venus, Jupiter, and the star Regulus.) The Moon goes through perigee, where it is closest to the Earth, on Sunday the 5th.

A day after lunar perigee, at 2;41 PM CDT on Monday, July 6, the Earth goes through aphelion, where it is farthest from the Sun, a distance of 94.507 million miles (152.093 million kilometers), 1.7 percent farther than average. That aphelion occurs during the high heat of northern summer tells that distance from the Sun has little to do with the seasons, which are caused by the 23.4 degree tilt of the Earth's rotation axis against its orbital axis. All things equal, the eccentricity of the Earth's orbit should produce wider seasonal swings in the southern hemisphere than in the northern, but the effect is largely absorbed by the oceans, which dominate the southern hemisphere.

Venus and Jupiter remain close together in western evening twilight, Jupiter the fainter, the two making a memorable pairing. Venus reaches maximum brilliance the night of Thursday the 9th, magnitude -4.7. A telescope shows it to be a crescent with only a sliver of daylight showing. If you know where to look, it's visible in the daylight sky. With Mars and Mercury pretty much out of sight, all that's left is Saturn, which by the time the sky darkens is already past the meridian low to the south to the northwest of Antares in Scorpius.

Valid HTML 4.0!