Mars / Venus conjunction in the morning sky

Over the last few years I’ve posted several articles about close encounters of the planetary kind and almost without fail have been rewarded with cloudy skies. There is another of these events taking place in the next few days, so fingers crossed for a beautiful crisp clear morning. 

On the morning of October 5 – you’ll need a good eastern horizon for this – Venus and Mars lie just over 20 arcminutes apart. A slightly gibbous Venus (91.5% phase, 11 arcsec diameter) at mag -3.9 dominates the eastern sky while a much fainter and smaller Mars at magnitude +1.8 and 3.7 arcsec diameter lies below it to the south-east. At this angular separation the two planets should fit comfortably inside a medium power eyepiece on most amateur telescopes, although binoculars may give a more aesthetically pleasing view. From London Venus rises at 04:52 BST with Mars a couple of minutes later. At 06:00BST (05:00UT) the planetary pair will be around 10 degrees (a closed fist held at arm’s length) above the eastern horizon with the Sun being about 11 degrees below the horizon. Sunrise on this day is at 07:08BST. 

If the sky fails to cooperate on this date, the following morning (Friday October 6) gives an almost repeat performance but with Mars now lying 22 arcminutes to the west of Venus. The Moon is busy in the west on these dates, so should not interfere.  Here’s hoping for clear skies. 

Mars of course is now on its way to opposition, which it reaches on July 27 next year. It will then sport a diameter of 24 arcsec and shine at magnitude -2.8.  The bad news is that from the UK it will only be around 11 degrees above the horizon!


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