Late Summer Waxing Moon

Who doesn't like looking at the Moon? It's such a treat for everyone, and is a lovely sight. For us Northern Hemisphere dwellers, there is a unique period of time each year in the late summer when the waxing Moon plays out across a low swath of southern sky, never getting very high into the sky. That unique period of time is now, and the Moon is making things more interesting by passing close to Jupiter and Saturn. 

For the last many days I've watched the waxing Moon emerge from the new phase into a thin crescent and then slowly toward first quarter. All the while it hugged the southwestern horizon, keeping low in the sky and making it more challenging to find. Now the phase has advanced to gibbous (between first quarter and full Moon) and all the while, the Moon only gets high enough to be seen if you have a clear view to the south. And for me, when I see this low-flung Moon, I know it is late summer. There is a technical reason for this. The waxing phases of the Moon occupy the sky where the Sun will be for the coming six months ... and that will be in the Fall and Winter seasons where the Sun does not rise too high above the southern horizon. There is a beautiful symmetry to the Sun and Moon and since we have one complete lunar phase every 29 days, we can see the entire flow of the seasons every month if we know how to look at the Moon. 

Over the past several years the late summer sky has featured Jupiter and Saturn low in the south. This year Jupiter will overtake Saturn in a series of 'conjunctions' which have already started, and will run their course by the end of the year with a spectacular alignment of the two planets in December (mark your calendar for Dec 21st). Saturn moves around the Sun very gradually from our point of view, and Jupiter faster but still quite gradual from year to year. The effect of these gradual movements is that these two giants have been lurking low in the southern sky during the Summer for the past years and for the coming years ahead. So as I've observed this unique time of year when the waxing Moon traverses a deep southerly course in the late summer, it's had the added beauty of a monthly encounter with Jupiter and Saturn. That will happen this week, on Friday 28th. You will need a clear view to the southeast to really enjoy the spectacle. And who knows ... perhaps you will discover this lovely configuration and the low waxing Moon in late Summer as something you will look forward to every year. I sure do. 

Image courtesy of Sky & Telescope. 

Perseid Meteor Shower 2020

The Perseid Meteor Shower has already started and will peak over the coming days, on August 11, 12 and 13th. This shower is one of the most reliable meteor showers of the year and as it peaks during generally warm weather for the Northern Hemisphere, it's a pleasant and easy-to-watch astronomical event that can captivate and amaze. 

Seeing the Perseids: seeing any meteor shower is easy, but getting the most out of the evening takes a little planning. First of all, you want to find dark skies, ideally away from city lights. Second, you need to reduce all local lighting to a minimum, including houselights and if possible, streetlights (for example, move to a part of a garden or park where streetlights are not directly visible). Third, you need a comfortable place to relax, ideally on a recliner chair or on a blanket on the ground so you can simply look up in all directions. Finally, you need to have warm clothing because even after a warm day the evening temperatures can drop quite quickly and if you are lying still in the open air, you will very quickly feel the effects and the Perseids will lose their appeal. 

There are two more factors that has a big impact on seeing the Perseids, one you cannot control (the phase of the Moon) and one you can (when to watch). The Perseids in 2020 are better positioned than some years because the Moon will not rise until well after midnight, allowing more viewing time in the late evening and early morning hours. In general, the best time to watch any meteor shower is after midnight (for reasons you can read about here), so your best bet is to get out late evening to start your viewing, and stay out until the moon rises (if you can stay awake that long!). 

Why are the Perseids so reliable? The Perseids, like most annual meteor showers, are caused when the Earth travels through a debris field that is also orbiting the Sun. In the case of the Perseids, the debris field is from Comet Swift-Tuttle. The American Meteor Society has an excellent article that explains some of the science of the Perseids, if you want to learn more. 

Best of luck, and clear skies! 

Image courtesy of NASA.