2017 Week 30: (July 23-29)

The final week of July has come and with it the last lunar cycle before the great solar eclipse.  There are several conjunctions happening throughout this week including the innermost planet Mercury.  If you have a view of the western horizon you might be able to pick Mercury out of the twilight as it will be less than a degree South of the Moon.  It will be quite close to the alpha star in Leo and shining twice as bright before you go to bed on the 25th.

Date	Event
July 23	New Moon
July 25	Mercury 0.9°S of Moon
July 25	Regulus 0.07°S of Moon
July 26	Mercury 1.1°S of Regulus
July 26	Mars in conjunction with the Sun
July 27	Southern Delta Aquariids Peak
July 28	Jupiter 3°S of Moon

July 26 also has Mars in conjunction with the Sun.  This means Mars will be tucking in behind the Sun and will start peeking out in the following months.  On July 27th in 2018 Mars will be at opposition, its closest since 2003.  However, for higher northern hemisphere observers it will be difficult to see properly.  It will be at nearly -26° declination.  This is lower than Saturn currently sits.  The atmosphere will give us bad seeing which will make it quite difficult for imaging.

The Southern Delta Aquariid meteor shower will also peak this week.  The radiant is, obviously, Delta Aquarii in the southern reaches of Aquarius.  Your best bet to see them will be between Thursday and Friday.  Look South in the middle of the night and catch perhaps 20 meteors per hour at their best.  An image of Aquarius with Delta Aquarii circled is shown below.  It is located at the bottom of the flow of water from the water bearer's flask.

Aquarius and Delta Aquarii

Jupiter is starting to go down with the twilight in the West and will be close to the Moon Friday evening.  If you're hoping to catch it through a telescope you better get your observing in before the fine details get swallowed in the atmosphere!

Astronomical twilight is finally over and Calgary can have some real night for the first time since the end of May.  This will be a great time to get prepared for another season of great observing!