Moon Flies By Mars, Space Station Flies At Dawn, Venus Flies Away

The first quarter moon along with Regulus and Mars light up the southwestern sky tonight. First quarter phase is one of the best times to see lunar craters in binoculars. Maps created with Stellarium

It feels like it’s been raining forever.  I have no hope of seeing the first quarter moon alongside Regulus and Mars tonight. That’s why I’m counting on you, fortunate sky watcher with clear skies, to be out there. Face southwest during late twilight and you’ll see the trio high up in the constellation Leo.

Remember how close Mars and Regulus were a month ago? They’ve since separated as the planet hurries eastward in its orbit.

Mars has faded, too. Look far to the left and high above the planet to see the similar-hued Arcturus.

Back in March, Mars outshone Arcturus. With its ever-increasing distance from Earth, the Red Planet has since shed more than a magnitude and now stands humbly in the great star’s shadow.

Mars on May 12. Credit: Damian Peach

Mars is very tiny even in a telescope with a disk only 8 arc seconds across (full moon is 3600 arc seconds). Determined amateurs may still be able to spot the shrinking north polar cap and larger dark markings like Syrtis Major. As the planet continues moving east, it will join Saturn and Spica in mid-August for a fine pair of conjunctions.

Summer’s been underway for the past two months in Mars’ northern hemisphere. Frozen carbon dioxide or dry ice vaporizes from the cap, causing it to shrink and develop dark rifts. As CO2 returns to the atmosphere, the world-wide pressure rises by 25% before the gas refreezes onto the south polar cap in southern winter.  On Earth, you could experience this spectacular rise in pressure by traveling from sea level to the top of a 9000 ft. mountain! Air pressure on our planet varies only a few percent as highs and lows come and go.

From the cupola on the space station, an astronaut photographed this Lyrid meteor burning up south of the Gulf Coast on April 22. Florida's at top and Cuba to the right. Credit: NASA

Now that the SpaceX Dragon cargo ship is docked to the International Space Station (ISS), we’ll have to wait until May 31, when the ship departs, for the next opportunity to spot the two together in the sky. Meanwhile you can still go out any morning in the coming week to see the ISS pass over your rooftop. Times below are for the Duluth, Minn. region. Click on Spaceweather’s satellite flyby site and enter your zip code or check out Heavens Above to find times for your location.  The station travels from west to east across the sky.

* Monday May 28 starting at 3:36 a.m. A high, brilliant pass in the northern sky.
* Tuesday May 29 at 2:44 a.m. Makes its first appearance high in the south. Very bright! Second pass at 4:17 a.m. in the northern sky.
* Wednesday May 30 at 3:24 a.m. in the north
* Thursday May 31 at 2:31 a.m. high in the north. Second pass at 4:06 a.m. in the north
* Friday June 1 at 3:12 a.m.  in the north
* Saturday June 2 at 2:19 a.m. and again at 3:54 a.m. in the north

Venus is low in the northwestern sky shortly after sunset this evening.

Seen Venus lately? It used to be so easy but now requires good planning. The bright planet is only about 5 degrees high in the western sky a half hour after sunset. You might even need to use binoculars to help you find it. Look to the northwest over the sunset point. Its crescent shape should be obvious using 7x magnification or higher. On June 5 it will pass directly in front of the sun in a rare event called a transit. I’ll provide a guide on how best to see it later this week.

8 Responses

  1. Tim Fleming

    Hi Bob,
    Here in St. Louis we haven’t had rain in about 3 weeks – I have to water like crazy to maintain the yard and garden. I have become familiar with Stellarium (through you) and I can now expand my knowledge of the night sky a lot more easily. I am about 20 miles west of the city and have pretty significant light pollution. A two hour drive southwest puts me in an area that is almost 0 light polluted. I use that area for meteor showers or when I need to really connect with the sky.

    Enjoy your holiday weekend.


    1. astrobob

      Hi Tim,
      Thanks for the good wishes. We did get some clearing at midnight Friday. I was pretty tired but figured what the heck and set up the scope. I’m nine miles from Duluth with significant light pollution in the southwest, but given a good night, the rest of the sky is very good. I hope you also have a great weekend.

      1. caralex

        Saw Mars and the moon last night – we’ve been having continuous sunshine in Hamilton for weeks now, and there’s no end in sight!

        On another note, not related to this post at all, but maybe you could give me a hint or two. I’m involved in a discussion on another site about the jaded old ‘we never went to the moon’ argument. (sigh!) I’ve put forward the LRO photos as evidence (pooh-poohed as photoshopped fakes), and another poster has mentioned the mirrors placed by the astronauts to measure lasers (sneered at as having been put there by unmanned probes).

        So Bob, what in your opinion, is the most water-tight argument you use to prove the astronauts went there? Is there absolutely anything you know of that can’t be countered by the nay-sayers?

        1. astrobob

          Nothing will work because it’s a set BELIEF not open to interpretation. For what it’s worth however, what about the 483 lbs. of moon rocks returned, thousands of pieces of which were investigated by scientists around the world? Or the thousands of people who built the rockets and launched them – are they all on it too? Neither of these of course will matter to the true believer of untruths.

          1. caralex

            Thanks, Bob. I’ll try those arguments. No doubt, though, the true believers in the hoax will find a reason to rubbish them!

  2. Eric

    Hey there astro bob,
    I’ve been reading about asteroid 2012 kp24 that is supposed to come close tomorrow. It seems there is little talk about this, but it worries me that it is only 0.1LD away. I also read that the distance has changed and it is now supposed to be closer. Any thoughts about this? Seems a little scary.

    1. astrobob

      0.1 LD or some 24,000 miles away or some 3 times our planet’s diameter. It’s a very small asteroid – about 75 feet – and will zip by us on its merry way. We know its orbit, it will miss Earth completely and doesn’t pose a threat in any way. Every couple months a small asteroid passes near Earth like this. Some come much closer, again without threat to the planet.

      1. Eric

        Thank you! Just trying to hear from someone who knows much more about space than myself. I guess I should stop reading articles from pseudoscience websites.

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