Upcoming Conjunctions Featuring the Moon, Mercury, Venus, Mars and Jupiter in May 2011
Submitted: Monday, 14th March 2011 by Mike Salway
During the month of May 2011, there are several early morning / dawn conjunctions that are worth getting up early to see. They feature the four closest planets (Mercury, Venus, Mars and Jupiter) as well as the thin Crescent Moon.
The last time we had a similar conjunction was in February 2009, and I can tell you from experience it was a wonderful event - make sure you don't miss these!
The 4 planets start converging close to each other in late April and form the closest conjunction on May 12th, when they are within 6 degrees of each other. After May 24th, the planets start diverging again and towards the end of May, Mercury will be so low that it will be very difficult to spot.
On May 12th (Jupiter, Venus, Mercury) and May 21st (Venus, Mercury, Mars), three of the four planets will be within 2 degrees of each other! Break out the wide field eyepieces and binoculars!
The thin crescent Moon joins the conjunction on May 1st and 2nd (though on the 2nd it will almost impossible to see), and again on May 30th and 31st.
Read on below for Sky Charts of this month of conjunctions, as well as more information about what a conjunction is, and how to photograph them!
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What is a Conjunction?
A conjunction is an alignment of 2 or more celestial bodies (usually the moon and planets) in the sky, from our vantage point on Earth. The objects aren't necessarily physically close to each other in space, but from where we see them, when the bodies are grouped close together on the sky we call them in conjunction.
When the objects get so close together that one passes in front of the other from our vantage point, we call that an occultation.
A conjunction doesn't have any particularly special meaning, but they can be interesting to observe because very close conjunctions are quite rare events. It can be very exciting to see two planets in the same field of view of your telescope!
Not only that, but conjunctions, especially with the moon and/or bright planets are involved, are just a lovely spectacle to look at and photograph. Who could forget the beautiful Smiley Face Conjunction of 1st December, 2008? Or the Moon and 3 planets conjunction on Feb 23, 2009?
Where and How Can I See Them?
The month of May conjunctions appear in the pre-dawn sky low in the East, and are best observed from around 60 minutes before dawn local time. They will be able to be seen until the sky brightens too much due to the rising sun.
In Sydney on May 1st, Sun rise is at 6:30am - so I'd be ready to observe by 5:30am.
All you need is a pair of eyes and a good unobstructed Easterly aspect. If you have trees or houses to the East, head to the nearest beach, lake or park to see the conjunction and watch the sunrise as well.
Sky Chart - 1st and 2nd May: Moon, Mercury, Venus, Mars and Jupiter
The four planets actually start converging in late April, and on the 30th April the Moon starts to join the show, forming a wobbly line starting from the Moon top left at an altitude of about 24degrees, followed by Venus, Mercury, Mars and Jupiter.
On the 1st May, the Moon drops down lower into the middle of the conjunction and will be a lovely sight. Mars and Jupiter converge even closer, and on the 1st and 2nd May they will be within half a degree of each other (the width of the full moon) - perfect for viewing in the same field of a telescope eyepiece (this doesn't happen often!).
On the 2nd May the Moon is still there but very low and very thin - probably impossible to see.
See the Sky Charts below for the view on the 1st and 2nd May. They simulate the view from approx 5:45am local time AEST in mid-southern (Sydney) latitudes.
Sky Chart - 12th May: Mercury, Mars, Venus and Jupiter
Between May 2nd and May 12th, the four planets converge to their closest point during the conjunction, where on May 12th they'll be within 6 degrees of each other.
Jupiter, Venus and Mercury will also be within 2 degrees of each other, with Jupiter and Venus the closest together at just over half a degree.
The trio will make a fantastic low-power view with binoculars and a higher power view of Jupiter and Venus through your telescope.
See the Sky Chart below for the view on the 12th May. They simulate the view from approx 5:45am local time AEST in mid-southern (Sydney) latitudes.
Sky Chart - 21st May: Mercury, Venus, Mars and Jupiter
Skipping forward another 9 days, and Venus and Mercury are moving down towards the North-moving Mars while Jupiter rises earlier and continues its journey higher in the sky towards the North.
Jupiter will be at approx 18 degrees altitude, while Mercury, Venus and Mars form a triangle between 9 and 10 degrees altitude. The trio will be within 2 degrees of each other, though at magnitude 1.3, Mars will be dimmer than Mercury (-0.1) and Venus (-3.78).
See the Sky Chart below for the view on the 21st May. They simulate the view from approx 5:45am local time AEST in mid-southern (Sydney).
Sky Chart - 30th and 31st May: Moon, Mercury, Venus, Mars and Jupiter
Heading towards the end of May, Jupiter continues to rise earlier and will be higher in the sky and further away from the other planets. Mercury starts sinking rapidly as it heads towards superior conjunction. Venus and Mars have a brief encounter on May 24th when they'll be approximately 1 degree apart.
The crescent Moon joins the scene again on the 30th May when it will be half way between Jupiter (23 degrees altitude) and Mars (9 degrees). The better view of the Moon will be on the 31st May when it forms a triangle with Venus and Mars, however they will be quite low, between 6-7 degrees altitude.
Mercury is likely going to be too low to observe easily at the end of May, however you may be able to see it for a short time before the impending sun rise washes out the sky. It will be very low though, and you'd need a very good easterly aspect.
See the Sky Charts below for the view on the 30th and 31st May. They simulate the view from approx 5:45am local time AEST in mid-southern (Sydney) .
How Can I Photograph Them?
Photographing these conjunctions is generally quite easy, and most cameras, even the compacts, will do a reasonable job of it however you'll get better results with the cameras that allow you to adjust the settings manually to capture a longer exposure.
In general, you'll need an exposure of around 1 to 4 seconds, so the tripod is a must. Of course with digital, it's very easy to preview your shot afterwards and adjust accordingly - so take lots of shots of varying exposures until the scene is well lit (not underexposed) but not overexposed in your preview screen.
It's easy to take pictures from home with powerlines or rooftops in the view, but the most pleasing shots will be the ones where you make an effort to get to a spot with a nice scenic foreground to compose with the conjunction in the sky. Make sure you give yourself plenty of time to arrive at your location, find the best spot and set up your tripod and camera.
The conjunction isn't over in an instant so you have time to recompose, try different settings etc, but remember that the dawn light can change very rapidly so it might help to go out a day or two before to find the best location and take some practise shots in similar conditions at a similar time of day.
References, Further Reading and Resources