The planets in our solar system orbit the sun in a plane, the “ecliptic plane”. Seen from the side within that plane from here on earth, they appear to travel in a line in the sky. As the planets travel in different orbits at different speeds, they sometimes seem to pass one another along that imaginary ecliptic line in the sky, as seen from here on earth. From the United States, the pass will occur between the mornings of January 6 and 7, 2018. Mars and Jupiter will pass within 1/4 degree, 1/2 moon width, of each other.
For the image above from the moon, Mars, Venus conjunction on February 20, 2015, I identified several locations to the conjunction as the moon and planets set over Mount Whitney, near Lone Pine, California. This time the planets will be about 3 times closer to each other.
Here are some actual photos of Jupiter and Mars approaching each other in the sky on recent nights:
Here’s a time-lapse of the planets rising on the morning of January 2:
The images and sample time-lapse were captured at a modest 200 mm focal length, the event will be more interesting when they are close enough to shoot at 300-400mm or more, their movement towards each other becomes even more obvious, and while the moons of Jupiter become even more apparent. The two planets will rise over the eastern horizon around 2:45 am on a zero degree horizon here in the Pacific time zone (at a compass angle of 112 degrees, a bit south of east), but I’ve been watching them past 6 am on recent mornings, so you can catch them from when they rise well into twilight. With my actual horizon being more than zero degrees, the planets will appear to rise closer to 3 am for me.
Here’s my result showing the progress of the planets, footage from the mornings of January 2, 3, 5, and 7:
Aside from the planets close together, what else might have been shot? With a long enough exposure and an interesting horizon, a time-lapse video of the planets rising could be interesting, somewhat like this prior shoot of a planetary conjunction setting:
I chose not to travel to an interesting landscape for this event due to a stormy weather forecast for much of the week here in the Eastern Sierra, including rain on January 6.