Cosmic Pursuits

Basic astronomy and night sky information

Solar System Observing

Articles about how to understand, find and see solar system objects including planets, the Moon, the Sun, asteroids, meteors, and comets with binoculars, telescopes, and the naked eye.

New Image of Pluto and Charon from ‘New Horizons’

by Brian Ventrudo Filed Under: Solar System

3-opnav3_plutcen_noano-1041_0Just 11 weeks left to go until the closest flyby of New Horizons by Pluto. These images, released on April 29, 2015, show Pluto and its largest moon Charon, which is as large as Texas, revolving about their common center of mass. You can also see Pluto rotating about its own axis, ‘like a chicken on a BBQ spit’. Most amazingly, there are surface features visible on the surface of Pluto including a bright patch at one of the poles. NASA explained that these surface markings are remarkably visible compared to other planets given the distance and size of Pluto. These constitute the most detailed images ever captured of the ‘former planet’. The view will only get better from here.

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See the Eta Aquariid Meteor Shower

by Brian Ventrudo Filed Under: Solar System

An Eta Aquariid meteor over the Devil's Tower in Wyoming (credit: David Kingham)
An Eta Aquariid meteor over the Devil’s Tower in Wyoming (credit: David Kingham)

The usually reliable Eta Aquarid meteor shower peaks on the night of May 5-6 this year. The shower runs from April 21 – May 20, 2015, with many meteors still visible for several days on either side of the peak. It is perhaps the best meteor shower of the year for southern hemisphere stargazers.

The annual Eta Aquarids occur as Earth passes through an stream of icy and dusty debris from the famous Comet 1/P Halley, more commonly called Halley’s Comet. We pass through a second stream of the comet in late October. This results in the Orionid meteor shower. So if you missed the comet during its last apparition in 1986, you can at least see sand-grain-sized bits of the comet burn up in the atmosphere during these two meteor showers.

The Eta Aquarids gets its name from the 4th magnitude star Eta Aquarii in the constellation Aquarius. The star is 168 light years away and bears no physical relation to the meteor shower. But the meteors appear to trace their paths back to a point in the sky near this star as the Earth moves into the debris field.

Because Aquarius lies on the ecliptic well south of the celestial equator, this is a better meteor shower for observers in the southern hemisphere. Rates of 30-60 meteors per hour are typical. Northern stargazers can see perhaps half as many near peak, but it’s still an impressive event. The Eta Aquarids on average are quite speedy and enter the atmosphere at 66 km/s (148,000 mph).

As with most meteor showers, the hours before twilight dawn, as the Earth turns into the meteor stream, are the best time to see the Eta Aquarids. You don’t need to find the star Eta Aquarii to see the meteors. They can appear anywhere in the sky. You don’t need any optics… just lie back under dark sky and look up.

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Jupiter Shadow Transit with an iPhone

by Brian Ventrudo Filed Under: Astronomy Images and Video, Solar System

Enjoy this short four-image GIF of the transit of the shadow of Ganymede across the face of Jupiter on April 14, 2015. Taken by Andrew Symes of Ottawa, Canada with an iPhone 6 and a Celestron NexStar 8SE alt-az telescope, this image also shows several belts and zones in the atmosphere of Jupiter including the prominent north and south equatorial belts, along with the possibly perpetual anticyclone of the Great Red Spot.

 

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April 30 – A Big Day for Mercury

by Brian Ventrudo Filed Under: Solar System

A photo mosaic of Mercury's northern plains, taken from orbit by NASA's Messenger spacecraft. (Credit: NASA/Johns Hopkins University)
A photo mosaic of Mercury’s northern plains, taken from orbit by NASA’s Messenger spacecraft. (Credit: NASA/Johns Hopkins University)

Just as the planet Venus passed close to the Pleiades last week, the smaller and more elusive planet Mercury will also skim this star cluster on the evening of April 30. The planet and cluster will be low in the northwestern sky after sunset, about 10º above the horizon in the northern hemisphere. This is a golden opportunity to spot the little planet before it heads back towards the Sun. And more remarkably, on the same day, NASA’s MESSENGER spacecraft, which has been orbiting Mercury for four years, will crash into the planet at more than 8,000 mph and end its long mission.

[Read more…] about April 30 – A Big Day for Mercury

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Venus, the Hyades, and the Pleiades at Sunset

by Brian Ventrudo Filed Under: Deep Sky, Solar System

Venus-Pleiades-2

The brilliant planet Venus is just over 2° from the Pleiades star cluster, while the V-shaped Hyades star cluster, which makes up much of the constellation Taurus, is to the left of Venus in this image. The constellation Orion is at extreme left. This image taken after sunset over the Ottawa River on a pleasant spring night on April 12, 2015.

Shining at magnitude -4.1 for most of the month, Venus is easy to find high above the western horizon as the Sun goes down. It outshines every object in the sky except for the Sun and Moon. The planet moves a little higher each night until early June.

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