The western sky just after sunset is exploding with beauty and it is well worth the time to spend a few minutes soaking it in. Right now there are three planets on display in the evening sky along with the fine winter constellations still visible as the glow of dusk fades. I have been watching this over successive evenings and am impressed with the variety of colors and patterns visible after sunset. This week the sun drops below the horizon around 8:00 PM pacific daylight time and the sky is reasonably dark by 8:30, but by 9:00 the best viewing emerges.
First up is the fast-moving planet Mercury which will spend the next few weeks making a strong showing in the western sky. Because it is so close to the sun it never moves far above the horizon, but we will be seeing it at one of the best views of the year. This diagram shows Mercury in a close encounter with the Pleiades on May 1st, but it will continue to hover in the west through mid-month. It is bright enough to be seen in the glare of the dusk sky and you will see it best if you have a clear western horizon.
Next is Mars which continues to share the limelight with the twin stars of Gemini, Castor and Pollux. Mars is distinctive in comparison to the Twins because of its deep orange color. It is slowly diminishing in brightness but is still bright enough to be easy to find.
Saturn is the highlight of the planetary lineup, high in the sky after sunset in the constellation of Leo. More on Saturn can be found in my last post.
The bright constellation Orion is now setting in the glare of sunset, slowly fading from view as the constellations of summer arrive in the east and begin their reign. Nonetheless, a very bright grouping is still visible in the western sky featuring three stars from three different constellations. A distinctive grouping of stars from different constellations is known as an "asterism" and the Winter Triangle is one of the more distinctive asterisms in the sky. It contains Sirius, the brightest star in the sky which is in the constellation Canis Major, Procyon, the brightest star in Canis Minor, and Betelgeuse, which is in the constellation Orion. This diagram provides a helpful guide to this pattern. Each of these stars have distinctive colors, with Betelgeuse an orange-red (it is a red giant star), Sirius whitish-blue, and Procyon in-between the two as a plain white star. Enjoy the sky this spring - it's full of remarkable things to see.
09 April 2008
It's Spring: See Saturn and Mars
This Spring there are two bright planets in the evening sky that you should stop and see when the weather permits. The first is Saturn, the second is Mars.
Saturn is well placed for viewing in the evening and is high in the sky after sunset. Saturn is currently spending several months in the constellation Leo and Saturn itself is near the bright bluish star Regulus which is the brightest star in Leo. They are nearly directly overhead in the evening, slightly to the south. Saturn and its famous ring system are very large compared to all the other planets and therefore reflect a lot of sunlight back to Earth. Saturn is a fairly colorless planet despite what you see in photographs which are often color enhanced. In natural light, Saturn is a blend of off-white, yellow and grey hues and therefore from our point of view looks like a medium-bright yellow-white star.
As Saturn travels in its 29 year path around the Sun, the ring system is more tilted toward Earth for a period of time and then less tilted toward Earth at other times. Sometimes we see the ring system edge-on and because it is so thin, it is very difficult to see the rings at all. For this reason, Saturn is sometime brighter and sometimes dimmer. Right now it is going through a brighter phase and with binoculars stands out as something other than a star. Find a comfortable spot (or lie on a blanket) and spend a few moments looking up near the highest point in the sky. In binoculars, Saturn looks like an oval, brighter than the surrounding stars and shaped differently than everything around it.
Mars is also well placed for viewing in the evening and is in the western sky after sunset. Mars is currently spending time in the constellation Gemini near the twin stars of Castor and Pollux. This diagram shows where to locate it later this week when the Moon passes near it on April 11th. Mars is one of the closest neighbors to Earth and when the alignment is right, can be quite bright. However, at this point it and the Earth are moving further apart and as such, it's brightness is fading from week to week. It still stands out among the stars, and of course it is a distinctive color of orange so it is easy to spot. But unless you know where to look, you might not realize it is a planet and instead think it is just another star. So use the Moon as your guide this week and take it in.
Happy viewing!
Saturn is well placed for viewing in the evening and is high in the sky after sunset. Saturn is currently spending several months in the constellation Leo and Saturn itself is near the bright bluish star Regulus which is the brightest star in Leo. They are nearly directly overhead in the evening, slightly to the south. Saturn and its famous ring system are very large compared to all the other planets and therefore reflect a lot of sunlight back to Earth. Saturn is a fairly colorless planet despite what you see in photographs which are often color enhanced. In natural light, Saturn is a blend of off-white, yellow and grey hues and therefore from our point of view looks like a medium-bright yellow-white star.
As Saturn travels in its 29 year path around the Sun, the ring system is more tilted toward Earth for a period of time and then less tilted toward Earth at other times. Sometimes we see the ring system edge-on and because it is so thin, it is very difficult to see the rings at all. For this reason, Saturn is sometime brighter and sometimes dimmer. Right now it is going through a brighter phase and with binoculars stands out as something other than a star. Find a comfortable spot (or lie on a blanket) and spend a few moments looking up near the highest point in the sky. In binoculars, Saturn looks like an oval, brighter than the surrounding stars and shaped differently than everything around it.
Mars is also well placed for viewing in the evening and is in the western sky after sunset. Mars is currently spending time in the constellation Gemini near the twin stars of Castor and Pollux. This diagram shows where to locate it later this week when the Moon passes near it on April 11th. Mars is one of the closest neighbors to Earth and when the alignment is right, can be quite bright. However, at this point it and the Earth are moving further apart and as such, it's brightness is fading from week to week. It still stands out among the stars, and of course it is a distinctive color of orange so it is easy to spot. But unless you know where to look, you might not realize it is a planet and instead think it is just another star. So use the Moon as your guide this week and take it in.
Happy viewing!
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