Mercury near Antares

Event Date: November 7th

Time: 5:30 AM

Brief

  Mercury is starting to quickly approach the Sun by losing separation with it, yet is still setting 47 minutes later this evening.  Since the Sun sinks below the horizon quickly after setting early, that means that we don't have to wait long to see it with binoculars or a telescope.  Waiting too long however, means that we lose it deep in atmospheric pollution.  It continues to wane, now at 27% as a fat crescent, and will continue to wane between now and inferior conjunction.

   Near Mercury, literally a little over 6º in separation is Antares: the huge, red star...and saying huge is almost an understatement.  Here the two are, including Mercury's orbit.

Detailed

When we look at Antares from Earth, even strong telescopes cannot magnify how huge it really is, because of its distance of 604 light years.  However, that 15th-century light that we see is from a "ball of fire" with a volume millions that of the Sun.  Its radii alone, is nearly 2,700 times that of our star, and a luminosity of over 387,000 times!  Go figure.  If Antares was even 200 light years closer, still putting it over 400 from us, its apparent magnitude would be unfathomable; put it this way...it would be too bright to see anything around us, even if we were immune from its heat and radiation.  Of course, the brightness would blind us instantly, even if not looking directly at the star.  Admittedly, I may be mistaken about the distance to get it so bright, yet the point being, we can see it as well as we can, even at over 600 light years away.

   Getting back to Mercury, try viewing it as a growing crescent, nearly 9 arc-seconds in size, before it gets too close to the Sun from our vantage point.  This image below shows it zoomed in at 200x to show the small planet as a crescent.  Do you notice it?

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