Cross your fingers for clear skies during the early evening hours of December 21st. While the 21st is the winter solstice, we're focused on other planets in the solar system, rather than Earth's place in orbit.
About every 20 years, the two most massive planets in the solar system seem to align and pass each other from our vantage point here on Earth, but this year is quite unique.
According to NASA
, it's been around 400 years since the planets passed this
closely to each other and nearly 800 (1226) years since it occurred at night, allowing Earthlings to see the two bright dots appear as one. Since we have a favorable orbital position and it occurs in the evening, nearly everyone who has clear enough skies will be able to view the event. I might add, you probably will want to catch this one since the next "great" conjunction won't occur again until the year 2080.
This conjunction has been slowly occurring for some time and will be interesting to watch over several days so, even if skies are cloudy on the
night, you can still catch a glimpse of the planets pairing up during the evenings around the 21st.
The closest apparent alignment will last for several days, but on the 21st they will appear so close your smallest finger should be able to cover them both at arms length away from your body.
The word "apparent" or "appear" is being used frequently because, although they will seem to be together, the planets will remain hundreds of millions of miles apart.
How to Watch
If you live next on the northeastern side of a large hill or mountain, you'll likely want to find a new place to watch the conjunction. But, unlike viewing conditions for a meteor shower where you want the darkest skies possible, you can see both planets even with bright city lights around you.
The planets will appear in the southwestern sky shortly after sunset and will be fairly low on the horizon. You'll see Jupiter first since it has the greater brightness or magnitude.
If you're watching in the days leading up to the conjunction, Saturn will appear just to the south and slightly above Jupiter. On the 21st, the planets will appear as one to the unaided eye, but if you use binoculars or a telescope, you'll still be able to see both separate through the lens.
Be sure to go out during or shortly after sunset, the planets will dip below the western horizon about an hour after the sun goes down.
How to Photograph the Great Conjunction
You won't need a professional camera to capture the conjunction since their apparent magnitudes are both so high. For additional tips, check out this NASA article.
Using a cell phone:
- If you have a newer phone with the capability of capturing long exposures, that's great, but it isn't necessary for this event. Zooming in won't enhance details so, for your standard shot, try to frame something or someone in the foreground with the planets to make it more interesting.
- Using long exposure or night mode will help show more stars and will make the planets appear brighter in your photos, just be sure to bring a tripod or something sturdy to balance the phone one while the lens is open.
- Depending on your phone's camera, you may not be able to see the planets separately in your photos on the night of the 21st.
Using a DSLR camera:
- As with all night sky photography, set your focus to manual and infinity to make all of those far away celestial bodies appear as crisp as possible.
- Bring a tripod or have something to put the camera on if you're using a zoom lens or creating a long exposure.
- Don't push the shutter speed to longer than a few seconds if you want the planets to appear crisp. Earth's rotation will make them appear blurry if the lens is open any longer than that. This effect is exacerbated with a longer zoom.
- If you have a 200mm lens or longer, you should be able to capture a few of Jupiter's largest moons and possibly the rings of Saturn. Just be sure to up your ISO and keep exposures on the shorter side.
Most global models agree on the general pattern for the evening of the 21st, with storm systems around the nation's northern corners and high pressure building from the Southern Plains into the Southeast. This favors clearer conditions across the southern states, but forecast details with both systems will still need fine tuning.
Check back to this article later this weekend for an update on the cloud cover forecast and, of course, by watching our live streams and broadcasts.