One astronomical year...almost "in the books"!

Event Date: February 18th

Time: 03:57(.44) AM

Brief

   We come back to Earth for this next entry, after viewing Mercury at its perihelion from millions of miles away....fun, wasn't it? :-)

For this one, I set the clock at an odd time, and hid the horizon.  The reasoning for this, is to show the Sun as it begins its final month of the astronomical year: crossing the 330º ecliptic longitude mark.  Now, why is this significant?  We are 30 da(y)tes away from the astronomical new year, which will also be the first anniversary of my first blog entry.  It is hard to believe that this time has passed already, yet that's just a personal thought!

   As mentioned above, the image below shows the sub-horizon Sun at ecliptic longitude 330º, with only 30º to go until reaching the March equinox longitude of 0º.  Also, take note of the celestial equator in the image, which I will elaborate on in the detailed.

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

Detailed

Although Mercury, Venus and some stars show in the image, I didn't label them, so as not to distract from the topic.  In the brief, I mentioned the celestial equator showing for a good reason: over the next 30 days, the Sun will increase in declination by almost 11 1/2º to reach where the ecliptic crosses the equator, being the equinox.  Similarly to how I showed the intersection of the lines, in the very first image of this blog on the date of the last March equinox, we can see it again here.  It is at that point that the Sun moves north at its fastest, and we get increased daylight faster than other times of late winter and/or early spring.  The opposite of course is true 180º away, at the September equinox longitude; our days shorten faster that that time.

   Keep an eye on the Sun (safely through an approved filter!) over the next month when it is above the horizon, and see if you notice a faster change in altitude at and near transit time.  One thing is for sure: the Sun seems much higher at transit on this date, than it did about two months ago during the week of the December solstice!