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 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.
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
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.