Winter Solstice Conjunction of Jupiter and Saturn

December 21, 2020

Jupiter and Saturn pass each other in our sky about every 80 years, but this time was the closest appearance in hundreds of years. From the earth they looked only 0.1º apart, so it took good eyes to see the planets separately. The conjunction coincidentally fell on the winter solstice, and therefore it was popularly called “The Christmas Star.” There has been a lot of conjecture over the years about what sort of star that the Magi saw rise to convince them to take a journey to see a newborn king. One of the most likely possibilities is some kind of planetary conjunction, and there were several in the general time frame of Jesus’ birth.

At twilight on December 21, I took my camera and tripod and set up on the sidewalk across the street from the dog park, where I had a clear view to the southwest across a soccer field. This is how it looked:

I used a telephoto lens zoomed to 400mm. I had tried a few shots several days before, but was still unsure about exposure, so I tried out different shutter speeds and left everything else constant. As I changed settings and took pictures, neighbors came along to see the conjunction for themselves. It was good to see and talk with them. I heard others gathered on Harper Lee a block over. So we had a mini neighborhood event.

My first shot included the trail from an airplane. You might be able to make out three of Jupiter’s moons.

All of my pictures overexposed Jupiter itself, but some less exposed ones got a decent view of Saturn’s rings.

With a lot more exposure, all four moons that Galileo saw in his telescope show up. Of course that makes both Jupiter and Saturn to be overexposed blobs.

Now I think I have a good idea how to photograph this, but I am not too likely still to be taking pictures 80 years from now when they have another close conjunction. I did not try to see or photograph them through my telescope. I don't have a clear view of that part of the sky from my house, and the tracking motor needs to be plugged in.

Now that I see how well I can photograph them with just a regular camera and telephoto lens, I want to try shooting them through my telescope. When I lived out in the country, I did take some pictures of Jupiter with a film camera. While the two planets will not appear close together, I should be able to take some good shots of them individually. Our planet goes around the sun much faster than they do, so we pass them about once a year. So maybe next year I'll get equipment ready and take their pictures.


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