2017 Week 20: (May 14-20)

We are officially moving into the 20th week of 2017 with a few nighttime sky events.

Date	Event
May 15	Double shadow transit on Jupiter
May 17	Mercury greatest elongation West (26°)
May 18	Last Quarter
May 18	Double shadow transit on Jupiter
May 20	Neptune 0.5°N of Moon

As mentioned last week the set of double shadow transits of Jupiter's moons has begun.  The evening of the 18th will be a great opportunity to witness this phenomenon.  Assuming good weather and no clouds I may open my backyard for a viewing opportunity.  Mercury will reach its greatest elongation West on Wednesday and will allow for prime viewing the following morning in the dawn sky.  The Moon will be waning back to a New Moon only visible in the early morning as it reaches Last Quarter.  Fortunately we had some good nights where the Full Moon was brightly beaming in the southern sky.  Finally, Neptune will be pretty close to the Moon next weekend.

When Mercury was approaching its greatest elongation East I was able to get a few pictures of this elusive planet.  Unfortunately it was with my non-tracking Dobsonian during a public viewing night.  I did not have enough time to properly capture the half phase that would be showing.

Mercury

For the people who like to stay up very late, Saturn will be prominent in the low southern sky.  It will look like an elongated sphere through binoculars.  If you have the chance to view it through a telescope the rings will be extremely conspicuous along with many of its moons.  It currently rises at quarter to Midnight and will be visible above the houses about an hour later.  Saturn will reach opposition on June 15 where it will be at its biggest and brightest as viewed from Earth.  Great time for imaging.

Mars, unfortunately is approaching conjunction with the Sun late in July and is currently fairly dim and small as viewed from Earth.  Its next opposition is July 27, 2018 in what will be close to a perihelic opposition (Mars will be very close to us due to its elliptical orbit).  2003 had a great perihelic opposition not seen in the past 60,000 years.  These oppositions provide the best time for seeing Martian features including the polar ice caps and Mons Olympus, the tallest mountain and volcano in the entire solar system.

If the sky is clear, look up, enjoy the spring constellations and the bright, beautiful planet Jupiter in the southern sky!