Moon's paths and waxing phase

Event Date: October 2nd
Time: 7:00 AM


Brief
 

   Yesterday, I showed Venus at transit, still several degrees from the Sun, as it moves towards superior conjunction early next year.  One of the better times to still view Venus however, is before Sunrise, or even the first several minutes during it, when the limiting magnitude of the sky is still low enough to see it easily.  Since we have reached the best time of the year for eastern morning geometry of the sky, Venus has maintained a good altitude at Sunrise over the last few weeks: its declination gap with the Sun has not shrunk much, as the Sun has been sinking south faster, being further east of Venus.  To further show this, here is the local and celestial paths plotted for Venus.  The ecliptic marks the Sun's celestial path, so to avoid redundancy, I left that out.  The paths for Venus cover the last two months, with the plots 5 days apart.

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

Detailed

  As seen above with the image, I "bent" the horizon to show more sky.  We cannot see the entire celestial path, since (1) Venus has picked up speed in prograde motion and (2) the sky has shifted slightly more than a degree every day.  As for the local path (green), we are only starting to see over the last 25 days or so of the 61, that it has started to lose a little of its declination gap with the Sun and therefore, rising a little later each day. 
As we get closer to superior conjunction, while the geometry of the eastern morning sky starts to fail quickly in January and February, the declination difference between Mars and the Sun quickly shrinks, with the Sun becoming more north by early-mid winter.
  Finally, as we look at the ecliptic, we see how it makes almost its steepest angle with the horizon at this time of year.  The Sun only about 5 minutes from officially rising, and Venus is an impressive 37º in altitude.  The Sunrise gap between the two is still 3 hours, 19 minutes this morning (Venus at 3:46 vs the Sun's 7:05) while the declination gap between the two is almost 16º.  In a few days, they will be a little closer to that 16º peak.
   This second image below shows Venus as a waxing gibbous.  The field is 1/4º, while the phase of Venus is 71% and 16 arc-seconds in angular diameter.  Since it is not completely "full", the way we see Venus near the time of superior conjunction, we only see about 11 arc-seconds of disc illuminated (about 71% of 16).  The magnification of Venus here is approximately 200x.