Event Date: September 1st
Time: 1:08(.31) PM
Brief
As we approach these last three weeks of summer, it is a time that we see the Sun move further towards the southern declinations as fast as we see all year. When looking at the image below, featuring the Sun, celestial equator and ecliptic, we see a decrease in altitude for transit happening each day. By looking left (east) of the Sun, the green ecliptic is seen coming towards the celestial equator and dipping below it. As the Sun follows this path, it dips more than 11º during the last month of summer, and that same number for the first month following the September equinox. I showed a similar scenario shortly after the March equinox, as the Sun spent the following 4 weeks becoming further north in declination, albeit slightly slower each day during that span.
The image here shown here displays the Sun at transit. The celestial guidelines mentioned, as well as the meridian, all show.
Time: 1:08(.31) PM
Brief
As we approach these last three weeks of summer, it is a time that we see the Sun move further towards the southern declinations as fast as we see all year. When looking at the image below, featuring the Sun, celestial equator and ecliptic, we see a decrease in altitude for transit happening each day. By looking left (east) of the Sun, the green ecliptic is seen coming towards the celestial equator and dipping below it. As the Sun follows this path, it dips more than 11º during the last month of summer, and that same number for the first month following the September equinox. I showed a similar scenario shortly after the March equinox, as the Sun spent the following 4 weeks becoming further north in declination, albeit slightly slower each day during that span.
The image here shown here displays the Sun at transit. The celestial guidelines mentioned, as well as the meridian, all show.
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| click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
As the Sun gradually gets lower at transit, it of course, spends less time above the horizon, By winter, especially the first few days, our star is only 29º above the horizon, or just shy of 1/3rd the way between the it and zenith. Right now, at about 8º north, the Sun transits just over 60º in altitude, or 2/3rds of the way between horizon and the sky, Although transit altitude is based on latitude, one thing is for sure this month: the altitude will always be the same number of degrees for the celestial equator. Therefore, for viewers at our global equator, the Sun transits at zenith at equinoxes. For viewers between there and 23 1/2º north and south of the equator, they also have zenith transits on other days of the year, depending on their exact latitude. For example, someone living at 11º north, somewhere in Central America, will have a zenith transit of the Sun around April 18-20st (depending on whether or not it is a leap year), and also around August 19-21st.
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