The Sun's local path

Event Date: April 8th
Time: 7:00 PM

Brief

   I talked about the local path yesterday with Venus, and mentioned how it can be helpful for tracking the position of a celestial body during a short period as well as a long one: less than 24 hours with the Sun above the horizon, or over 24 days in the case of a planet.  To demonstrate the former, the images show the local path of our Sun from rise to set today, with the markers measuring where it is at the top of each hour.  In comparison to Venus, for which the markers measured every 10 days for a 7-month span, notice the difference for today's entry: the first image shows the eastern half of the sky up to the meridian directly south, and the second shows the western half of the southern sky, up to the azimuth of the setting Sun.

 

 *click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

Notice that even though I kept the ecliptic in the images, it is not to distract; it is to emphasize that when I include the ecliptic in other entry images, past and future, that it only shows the Sun's annual path, hence my showing the local one today.  The celestial grid is included as well as a reminder of the curve that the Sun makes towards the horizon, depending on its declination.  Now that the Sun is moving further north of the celestial equator, it is reaching the gridlines that make gradual curves to the horizon.  The result of this is visible to us as we view the Sun (safely, please!) rising and setting: it is seen rising more north of both east and west, and as seen from latitudes far enough north, never setting at all.  Each day that passes between now and the summer solstice, the less north a viewer has to go to see a circumpolar Sun.  After the solstice, between then and the equinox, such a trek further north would be required, as the Sun moves back towards the celestial equator.