Mercury's evening apparition

Event Date: June 14th
Time: 9:00 PM

Brief

   Mercury continues to emerge from the Sun in the west-northwest.  Look for it still high enough above atmospheric pollution during the end of civil twilight, and still an impressive magnitude of -0.4.  Since the planet sets an hour and a half after the Sun, thanks to a declination slightly higher than the Sun's and becoming more separated, we have about 30 minutes to see it easily with the eye, and another 20-30 minutes sandwiching that span with optical aid.  Here is Mercury during the last minutes of civil twilight.

Detailed

   As I often remind, viewers high enough up to not have obstruction in the way are able to see it for longer durations than those with obstruction.  As a waning gibbous, we are seeing a decent amount of Sunlight still reflecting off of its disc.  As the evening geometry becomes worse in this part of the sky over the next several weeks, along with Mercury's dimming, this is the last week to see it with the eye alone after Sunset; it will sink deep into atmospheric pollution.  It passed perihelion at about the time of superior conjunction, meaning that as it continues to approach aphelion over the next few weeks, it will start dimming very rapidly.  After greatest elongation, it will be nearly lost from naked eye view for the rest of the time east of the Sun this month and early July.  We will get it back in better view starting in late July when it is west of the Sun again in the morning.
   This second image shows the gibbous phase of Mercury 70%.  This waning will be gradual between now and inferior conjunction. I left the planet unlabeled below, to avoid distraction from viewing the small size compared to other planets.  The angular size is 6.1 arc-seconds, with an 8 arc-minute field.

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