a guide to the sky
How to enjoy the encounter The separation between Jupiter and Saturn will gradually decreases , becoming smaller than the apparent size of the full moon from around December 17th , and becomes the smallest around December 21st , about one fifths of the apparent size of the full moon . Then the separation increases . Around December 26th , it exceeds the apparent size of the full moon . Let ’ s observe this change with the naked eye ( glasses and contact lenses can be used ). In the old days , Ursa Major ’ s Mizar ( 2.2 mag ) and Alcor ( 4.0 mag ), which are 12 arcmin apart , were used for visual acuity measurement . Jupiter ( -2.0 mag ) and Saturn (+ 0.6 mag ) are brighter than Mizar and Alcor , although they have a larger difference in brightness . Try to watch Jupiter and Saturn without using a telescope or binoculars when they are very close . Can you distinguish them ? Also , from December 16th to 17th , there is a thin moon near Jupiter and Saturn , so let ’ s enjoy the appearance of Jupiter , Saturn and the Moon , and the change in their arrangement . With a telescope , you can also see moons of Jupiter and Saturn , Jupiter ’ s bands , and Saturn ’ s rings . Around the closest approach , you will see Jupiter and Saturn in the field of view at the same time . Of course , you will see the satellite , Jupiter ’ s bands and Saturn ’ s ring at the same time . Such a scene will not be seen even with a low-magnification telescope until 20 years later ! If you have a camera , take a picture and keep a record . You can also take a picture with a smartphone camera . It ’ s very likely that auto shooting won ’ t work , so familiarize yourself with the manual shooting method of the camera in advance . Focus on infinity and try with different ISO sensitivities and exposure times . If you have a tripod , you can shoot without worrying about camera shake . Jupiter is the brightest star at 19 o ’ clock in the western sky in December , so it is quite easy to find Jupiter . Although Saturn is fainter than Jupiter , Saturn is as bright as 1st magnitude star . The sky gets darker and darker after sunset . In late December , Jupiter and Saturn appear in the low sky in the west . They fall soon , and you can enjoy observing these planets during short time in the evening .
COURTESY OF Software Stellarium
These are simulations of the position of Jupiter and Saturn in the night sky on December 21 in the Southern Hemisphere ( above ) and the Northern Hemisphere ( below ).
Let ’ s share your experience If you see or take pictures of Jupiter and Saturn , let ’ s share them online . Please report whether Jupiter and Saturn were seen as two or one with the naked eye from the website of “ Night Vision Experiment ( tentative title )”. If you are happy to see it , let ’ s share the impression on SNS etc . If you can shoot , let ’ s share it on SNS . Astronomers Without Borders provides a website to enjoy the close encounter of Jupiter and Saturn all over the world and share their impressions and records . Please post them . Even if you don ’ t have a telescope at home , there may be a viewing party nearby . Search for information , such as on the Astronomers Without Borders website . There are also observatories that will live broadcast Jupiter and Saturn online with a telescope . Jupiter and Saturn can only be seen for a short time in the evening . When you cannot see them , they can be seen in other countries or regions . Share emotions and photos and connect with others around the world .
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