Astro Bob: Count 'em! — Four planets at dawn and more solar excitement on tap - Duluth News Tribune | News, weather, and sports from Duluth, Minnesota

Planets April 18.jpg — Jupiter is now departing the solar glare and joins Venus, Mars and Saturn at dawn. Connected together, the four planets create a "rising curve" of visual enjoyment. The numbers indicate the separation in degrees between each planet. One balled fist held at arm's length spans about 10° of sky.

By Bob King

April 17, 2022 02:33 PM

DULUTH — I tried to see the planets Sunday morning, April 17. The forecast looked perfect, but I awoke to clouds. You know the feeling. While I await the next clear morning, let me share the good news: Jupiter has returned!

Along with Venus, Mars and Saturn, we now have four planets lined up in a row 30° long across the southeastern sky at dawn. With the exception of Venus (an inner planet), each has popped out in succession at dawn over the past couple months. There's a reason for that — the sun has passed them by.

Solar motion — On April 17, 2022, the sun and Jupiter are separated by about 32°. Compare this view to a month from now.

The sun's apparent motion to the east outpaces the slower movement of the outer planets and leaves them behind. Remember that the sun's apparent motion is just that — apparent. It only appears to move because the Earth orbits it. After it passes each planet in conjunction, the two gradually separate. Post-conjunction, the planet rises before the sun. Over time, their separation increases — the planet rises earlier and earlier — until it's up at midnight and finally appears in the evening sky.

Venus is a little different because it orbits inside Earth's orbit. We see it swing from one side of the sun to the other, but it can never stray more than 47° to either side, the reason it's only visible at dusk or dawn.

Sun motion B — A month from now on May 17, the sun and Jupiter will be 55° apart, with Jupiter appearing in a dark sky before the start of dawn. The sun's eastward motion increases the separation between the two bodies. If you compare Jupiter to where it was last month, you'll see that it has also moved eastward (caused by its orbital motion around the sun), but too slow to outpace the sun.

While it's pretty cool to see all four planets strung out like tiki lamps at a pig roast, they're only the table dressing for several spectacular, upcoming conjunctions, including a super-tight pairing of Jupiter and Venus on April 30. More about that in an upcoming article.

Big sunspots return — I took this photo of the sun through a small, filtered telescope around 10 a.m. CDT on Sunday, April 11. Five sunspot groups are visible. The two new groups — regions 2993 and 2994 — each has a spot considerably larger than the Earth.

After a few days of relative quiet, the sun is bursting with fresh activity with the appearance of two large sunspot groups, regions 2993 and 2994. They both recently rotated onto the solar near side and are extremely easy to see in a small telescope equipped with a safe solar filter.

X flare — This photo from NASA's orbiting Solar Dynamics Observatory captures the spectacular X-class flare in Region 2994 in far ultraviolet light. The blast occurred around 10:30 p.m. CDT, April 16.

Region 2994 kicked out a serious X-1 class flare late on April 16 Central Time. While it wasn't directed toward the Earth, both groups seem ripe for more flares in the coming days that could set off auroras later this week or early next. I'll be in touch!

Astro Bob: Count 'em! — Four planets at dawn and more solar excitement on tap

Jupiter joins the morning planet crew, and two large, new sunspots mix it up.