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Equinox sun is over Earth’s equator
The equinox is September 22. From around the world on the day of an equinox, the equinox sun pretty much rises and sets due east and west.
September 22, 2021
Year’s fastest sunsets happen around equinoxes
The year's fastest sunsets are at the equinoxes, and the slowest are at the solstices. We're talking about the minutes needed for the sun to sink below the horizon.
September 21, 2021
Harvest Moon 2021: All you need to know
In 2021, the Northern Hemisphere's Harvest Moon falls on September 20, or less than 2 days before the autumn equinox.
September 20, 2021
Ceres at opposition, coming up November 27
Ceres at opposition on November 27. Now begins the best time to observe it. In the first few days of November, Ceres will sweep past bright Aldebaran.
September 20, 2021
What are red giants?
What are red giants? Most main-sequence stars, like our sun, will become one. Red giants swell to such a large size they can swallow their inner planets.
September 17, 2021
Are day and night equal at the equinox?
Are day and night equal at an equinox? No. Earth's atmosphere and our sun team up to give us more day than night at an equinox.
September 16, 2021
Mercury greatest elongation September 14, best for S. Hemisphere
Watch for Mercury from Southern Hemisphere locations in late August, through September, 2021. Meanwhile, from northerly latitudes, bring binoculars!
September 13, 2021
Neptune at opposition September 14, 2021
Neptune at opposition - 180 degrees from the sun or opposite the sun in the sky - on September 14, 2021. You need optical aid to spot it. Links to charts here.
September 13, 2021
Zodiacal light: All you need to know
The zodiacal light is an eerie light extending up from the horizon before true dawn begins. Southern Hemisphere? Look after sunset!
September 6, 2021
Visible planets – and more – in September 2021
Visible planets in September 2021. Venus, Jupiter and Saturn bright in the evening from all of Earth. Mercury grand for the Southern Hemisphere.
September 1, 2021
