2020 Great Conjunction

Close conjunctions of Jupiter and Saturn are known as Great Conjunctions, and they occur about every 20 years. Occasionally they can be very close, and 2020 was such a year, with the planets coming within 0.1° of one another on the solstice, December 21. It has been 400 years since they were so close, and it will be 60 years until they are this close again.

The two planets have been striking for much of the year, slowly moving together, then apart, then together again. Both were in conjunction with each other near their solar conjunctions, meaning they were far away from us, on the opposite side of the Sun in their orbits. This made imaging the conjunction tricky, because it was low in the evening dusk sky and because the planets were fairly small and dim compared to how they are near opposition. I made two kinds of images: fairly wide field shots using conventional camera equipment, and telescopic images from my observatory. The latter was made especially challenging because my observatory wall blocks more than half of my telescope aperture for objects so low. And at high magnification, the combination of low altitude and Colorado's typically unstable air made for very distorted seeing. I took hundreds of images in order to get one that was reasonably steady.

Seeing Animation This is a 32-frame animation collected over 16 minutes (31.5 seconds between frames, each of which was exposed for just 0.02 seconds) from UT 00:34 to 00:50 (17:34 MST), showing the effects of the observatory wall, occasional tree branches, and a turbulent atmosphere on the images. The image in the gallery below was sorted from hundreds of images to find the one with the best seeing.


Gallery

Click on images to enlarge.

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