Mercury's morning apparition: both hemispheres

Event Date: April 13th
Time: 6:00/6:30 (see detail)

Brief

   Although finding Mercury in the dawn sky now is still very challenging, it is getting slightly easier each week, as the planet brightens.  Whereas it as at perihelion in early March, it is now very close to aphelion, and as a result, brightening slower than average.  Aphelion happens tomorrow evening.  With Mercury coming slowly back towards the Sun, it means that the rate of brightening will slowly increase.  Take a look at Mercury below, now at magnitude +0.6, and notice via its orbit that it is nearing greatest western elongation.

 

Detailed

At this time of year, when Mercury is this far separated from the Sun, it is about as much so as it is all year.  The aphelion is more clear, giving it a current separation of almost 27º.  In the southern hemisphere at similar latitudes, viewers there get a treat that we do not here.  That is, when we see Mercury at its best apparition, similarly to how we have seen Venus over the last month, we only see it that way at perihelion and therefore, it only gets as high as 18º in altitude at locations with the best apparitions.  For southern viewers, they seen Mercury at the aforementioned 27º-- or as much as 28º, depending on how close it is to greatest elongation and the exact week of the spring. 
This 2nd image shows an image of the view from Box Hill Austrailia, which has a southern latitude of precisely the same as our northern one: 37º 49'.  Being in a different part of its time zone, I set the clock forward half an hour ahead, meaning Mercury can be seen even slightly higher without the Sun's glare getting in the way.

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

Never mind right now, that the ecliptic and celestial equator are reversed in direction; I will talk about that at a later date.  For now, just look at Mercury in orbit, reaching greatest elongation.  At our latitude, Mercury barely rises or sets more than 90 minutes before/after its best greatest elongation apparitions.  When further separated from the Sun as shown, Mercury rises or sets more than two hours (120 min) before/after the Sun...lucky dogs!  Some of the best views of Mercury happen just south of our equator, when the rise/set interval is closer to two hours, 30 minutes.