Latest sunrise tomorrow

Look on the morrow’s dawn, ye sluggards, and have hope.

See the end note about enlarging illustrations.

The date when the Sun rises latest seems (at any rate for early risers) the shortest day and in that sense the pit of winter.  That date is January 5, if you live at or near latitude 40 degrees north.  The date varies with latitude, getting closer to the December solstice date with higher latitude.

The time of sunrise at 40 north will be 7:22.  Of course the Sun will appear minutes later than that if you have a high horizon of buildings or mountains.  I have a cliff horizon across the bay in summer, and a sea horizon now because the Sun is rising so far south that it’s far off the end of the headland called Portland Bill.

The slender Moon comes down through this pre-dawn scene,.  The figures beside the Moon dates are its “age”: the number of hours from the New moment.  Thus on Jan. 4 (at the same place and clock time) it was 37 hours before  New, and on Jan. 5 the invisible Moon is 13 hours short of passing the invisible Sun.

When it does that, on January 6, it will pass close enough south of the Sun to be partially in front of it.  But this partial eclipse, centered on 1:29 Universal Time, will be visible from the southern Pacific, a coastal fringe of Central America, and South America except for its northern fringe.

Beyond the invisible underground Sun is the invisible Saturn, which was at Sun-conjunction on January 2.  But Jupiter and especially Venus are up and bright.  Minutes earlier, though lower, they would be in a darker sky.

On that Moon is now a new visitor.  The Chinese spacecraft Chang’e 4 became on January 3 the first to land on the Moon’s far side.  Chang’e (the apostrophe in the transliteration of the Chinese word separates two syllables) is now exploring the South-Pole-Aitken Basin, which is the largest known impact basin in the solar system.

You’ll see or hear statements that Chang’e is visiting “the dark side of the Moon.”  All sides of the Moon receive sunlight as it rotates.  The “dark side” phrase has stuck because of the words of a Pink Floyd song: “I’ll see you on the dark side of the Moon.”  According to an article today: “Listen carefully as the album’s climax fades to leave a thudding heartbeat and you’ll hear Gerry O’Driscoll, the doorman to Abbey Road studios where it was recorded, saying: ‘There is no dark side of the moon really. Matter of fact, it’s all dark.'”Doorman Gerry O’Driscoll may have just been irreverent, or he may have known not only that the Moon has a side never turned toward Earth and no side never turned toward the Sun, but that its surface is of such dark material that it is more like tarmac than sugar.

Two further quiz questions:

– Who was the doorman, or caretaker, at a French observatory who picked up astronomy and became the greatest visual comet-discoverer of all time?

– What poem am I parodying with “Look on the morrow’s dawn, ye sluggards, and have hope”?

__________

DIAGRAMS in these posts are made with precision but have to be inserted in another format.  You may be able to enlarge them on your monitor.  One way: right-click, and from the drop-down list choose “View image”  Or from that list choose “Copy image”, then put it on your desktop, then open it.  On an iPad, tap with three fingers to enlarge. I would be glad to know whether these work for you, and what the equivalent actions are on a phone.  I would welcome learning of any other methods.