A Case Of Conjunction-Itis / Mars Dust Storm Global But Weakening

The moon approaches and then passes Jupiter over the next two nights. Jupiter is still near Libra’s brightest star Zubenelgenubi. Stellarium

Over the next week, the waxing and then waning moon will pass three bright planets — Jupiter, Saturn and Mars. First to get a visit will be Jupiter both tonight and tomorrow night (June 23). Saturn follows on June 27 and Mars on the 30th. The moon moves faster across the sky because it’s so much closer to Earth. That’s why it repeatedly laps the planets month after month. The close approaches are called conjunctions, and we’re grateful for them not only for their beauty but also because the moon helps us find these objects with ease.

Saturn accompanies June’s Flower Moon later this month in the constellation Sagittarius. Stellarium

Of the three only one will be a close conjunction.  On Wednesday the 27th, the Full Flower Moon will pass just 1° (two full moon diameters) above the planet. What a sweet sight that will be — watching the full moon rise with a planetary companion. That’s also the same night Saturn reaches opposition, rising at sunset and staying in view the entire night. The ringed planet will also be closest to the Earth that night. Time to get out that scope you as a gift and enjoy the planet’s stunning rings.

Mars and the cavort in Capricornus on the 30th. Stellarium

The Mars conjunction happens three days after full moon, so you’ll have to stay up a little later to see it. It’s so easy to see these beautiful pairings because it’s summer, and many of us are outside later than usual. Mars is in the news again because its dustier than a dirt road in mid-summer.

But recent photos taken by Australian amateur Anthony Wesley indicate that the dust may be starting to clear. His image from June 21 still shows plenty of suspended dust, but the dark albedo features Syrtis Major and Sinus Meridiani are beginning to show through the haze. There’s also a prominent dark collar along the northern border of the south polar cap.

Some of Mars’ better known features are beginning to show through the dust in this photo taken on June 21.8 UT. The prominent dark “thumb” is Syrtis Major. Anthony Wesley

I finally got a good view of Mars on June 21 at 4:30 a.m. Central Time through a 10-inch telescope and saw parts of two dark markings, Mare Sirenum and Mare Cimmerium. The polar cap, which would normally be distinct, appeared pale-white and patchy using a magnification of 254x. You could see it was there but the outline was unclear. There’s plenty of time for potentially great views with opposition still more than a month away.

Two images from the NASA’s Curiosity rover show the change in the color of light illuminating the Martian surface since the dust storm engulfed Gale Crater. The left image shows the “Duluth” drill site on May 21; the right image is from June 17. The cherry red color in the post-storm photo is due to is due to a couple of factors: the exposure time for the right image is nine times longer than the one on the left because of low-lighting conditions brought on by the dust. But the primary reason for the color change is that the dust filters out most of the green and all of the blue light from the Sun. Right now, the light resembles that when heavy forest fire smoke fills the air. NASA / JPL-Caltech / MSSS

NASA attempts to contact the Opportunity rover every day, but there’s still no reply. Meanwhile, the Curiosity rover on the other hemisphere of Mars has been recording thickening dust conditions. In other news, the storm is officially a “planet-encircling” or global dust event, according to Bruce Cantor of Malin Space Science Systems, San Diego, who is deputy principal investigator of the Mars Color Imager camera on board NASA’s Mars Reconnaissance Orbiter. This storm’s more patchy compared to the big global storms of 1971-72 and 2001 which totally obscured the surface.

A self-portrait taken by NASA’s Curiosity rover taken on Sol 2082 (June 15, 2018) at  the “Duluth” drilling site. (center). A Martian dust storm has reduced sunlight and visibility at the rover’s location. NASA/JPL-Caltech/MSSS

6 Responses

    1. astrobob

      Hi Carol,

      Astronomers are still trying to work out why some go global and others don’t. No definitive answer yet. The lack of water on the surface may be a factor. It’s pretty much desert everywhere.

        1. astrobob

          Hi Carol,
          I’m not sure about the pressure — that certainly makes 60 mph Martian winds not much more than a breeze. But I do know that gravity is a factor — it’s considerably less on Mars, so it’s easy to get particles aloft and keep them there longer than on Earth, where gravity is stronger.

  1. kevan Hubbard

    Spotted Mars last night, or technically this morning, at about 00:30 hrs..very low but very bright.my big Russian 20×60 binoculars resolved it into a round disk bigger than Jupiter I should say.if it was higher I reckon even at 20x you might get a few surface details like ice caps such was its size but too much atmosphere(earths)thickness where it is now.5 planets in the one night see;earth,Venus, Jupiter,Saturn and Mars.spotted some nocculant clouds too.

    1. astrobob

      Hi Kevan,

      Cool that you saw a disk. Mars however is only 19 arc seconds across and Jupiter is 42 arc seconds or more than twice as large. I wish you could see surface details at 20x but unfortunately Mars is so small you’ll need at least 50x. Even that’s barely enough to see anything at the moment because of the dust storm. It’s the best however that all five planets are out at once!

Comments are closed.