The waxing gibbous moon will swell to full on Saturday, and while this is a near monthly occurrence, this lunar cycle is special.
May 21 Blue Moon will be near red Mars. This full Blue Moon and the red planet Mars will shine together all night long, from dusk May 21 until dawn May 22. Of course, the moon will be blue in name only. But red Mars will really be noticeably reddish in color, and the full moon and Mars are guaranteed to be spectacular to view on this date.
Earth will pass between Mars and the sun on May 22. Astronomers call that an opposition of Mars, because Mars will be opposite the sun, rising at sunset.
Likewise a full moon rises at sunset. And that’s why Mars is near the moon on May 21, when the moon is full and Mars is just one day from opposition.
Currently Environment Canada is calling for cloudy skies through Saturday night, which could hamper your view of the blue moon.
Agencies/Canadajournal