Saturn, Spica and the moon late tonight in the southeastern sky. Created with Stellarium
Tonight the moon rises around 10:45 p.m. in the southeast, but if you wait until 11:30 or so, you’ll get to see it lined up “single file” under Spica and Saturn. The moon will be about 4 degrees below Spica and double that distance from Saturn. If you’ve been having difficulty finding Saturn, let the moon give you a hand this evening.
Another interesting if invisible series of lineups or conjunctions are happening near the sun today in the daytime sky. Mercury, Mars and Neptune are gathered together only a few degrees west of the sun.
Solar glare and the bright blue sky make this event impossible to see here on Earth, but from the Solar and Heliospheric Observatory (SOHO) in space, it’s a no-brainer.
This photo of the sun and planets was taken by the SOHO coronagraph on the 19th, when the planets were nearly lined up. I've drawn a circle indicating Neptune's location, since it's just a tad too faint to show. The short streaks are caused by cosmic rays striking the image sensor. Credit: NASA/ESA
SOHO studies the sun’s outer atmosphere, called the corona, using a coronagraph with an occulting disk that covers the sun and block its glare. That way it can get in close enough to study the movements of hot gases that compose the corona. The field of view of the coronagraph is large enough to include numerous background stars as well as the occasional comet or planet that wanders by.
If we could float above the plane of the solar system, we'd see that Mercury, Mars and Neptune are at vastly different distances from Earth. But from the point of view of an Earth-bound observer (black arrow), they appear to be lined up near one another in the sky. The numbers stand for the planets' distances from our planet in millions of miles. Solar system not to scale. Illustration: Bob King
Mercury, Mars and Neptune all lined up under one or another yesterday and today for a series of three conjunctions. Planetary alignments give us the opportunity to understand the layout of the solar system. They’re also are a reminder that our inability to perceive depth in the sky creates the illusion that celestial objects are close to each other when most of the time they’re not.
You can use this understanding when you go out to see the moon-Spica-Saturn lineup tonight. In that situation, the moon will be much closer to us than Saturn. Saturn in turn is much, much closer than Spica, which glimmers at a distance of 250 light years or some 1,500,000,000,000,000 miles. That’s 1.5 quadrillion miles. Yikes, I think we’ve gone far enough.
Nice and informative, as usual! That’s why they say in case of dealing with large sums of money they should invite an astronomer, only he’ll be able to manage the astronomical amounts! Speaking seriously, all these distances are quite hard to be imagined. By the way, I tried to catch Saturn lately, but failed to single it out…If this little line-up continues for just two days, I’ll have a perfect time and place to find Saturn at last!
Thank you Sunny. If I remember right, you’re at more southern latitude. Saturn and Spica are nearly equally bright and may look horizontal to each other unlike we see them in mid-northern latitudes. Look more toward the eastern sky rather than southeast around 11 or so.
Thanks, Bob, I’ll try!))