THE DAILY ASTRONOMER
Wednesday, July 31, 2019
Black Super Moon Rising
         "Look on the bright side of life."
                            -Eric Idle


Not visible.  The blank, non-image above is the best representation of the black moon, a celestial object that Earth-bound observers won't be able to see tonight.

We would advise you to watch for the black moon tonight if it were actually visible.  As it isn't, there will be nothing to see.   The "Black Moon," is merely the second new moon of the moon.  The "Black Super Moon" is the second new moon in a single month that occurs when the moon is at or near perigee, its point of least distance from Earth.       Like the "Black Moon," the "Black Super Moon" is not visible because the new moon occupies the same region of the sky as the Sun.


moon_above.gif
NEW MOON:  The moon is "new" when it is passes between the Sun and Earth.   Unless the moon is moving directly in front of the Sun, Earth bound observers won't see the new moon.     Successive new moons -like successive full moons- are separated by 29.5 days, a span known as a "synodic period."    As a synodic period is less than 30 days, any calendar month, save February, can contain two full moons or new moons.  The second full moon in a month is called a "blue moon," while the second new moon is called a "black moon."  

The moon was new on July 2nd and will be new again in the late evening on July 31st here in the eastern United States.    The black moon will be among the last of the celestial events for July 2019.    

The moon will next reach perigee, it point of least distance from Earth, on August 2nd.   As the moon will be new just before this next perigee, we'll also have a "super moon," defined as a moon that is at its largest due to its close proximity.  Of course, this time, the moon doesn't truly appear to be at its largest because it isn't visible at all.    Then again, we'll make any excuse to use the term "super moon," so common sense is inconsequential.  

Tonight, when you're outside admiring our beautiful summer night sky, be sure to not look for the invisible black super moon: a moon that would appear larger than a regular invisible moon were we actually able to observe this invisible moon, which, by definition, we can't.