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  • Rapt in Awe

    My Journey through the Astronomical Year

    Think of this as a "companion text" to this, the main web site. Not required reading, butI hope you'll find it interesting and helpful.

Events July 2013 – Hey wave – you’re on Cassini Camera!

NASA art work show how Earth might look from Saturn on July 19, 2013.

NASA art work show how Earth might look from Saturn on July 19, 2013.

Hello Saturn! Hello Earth!

NASA will help put things in perspective when you view Saturn in the southern sky on July evenings in 2013 – the space agency will show you what it’s like for Saturn to look back and view Earth!

That’s right – NASA is promising us a view from Saturn of our home planet and that’s just the sort of thing that’s fun to try to get your mind wrapped around. I’m sure it will provide us with some perspective and you can enhance your experience by first being sure to find Saturn in Earth’s evening sky – an  especially easy task this month!

Simply go out an hour after sunset and look a bit west of south – there are two bright “stars”  about a third of the way up the sky and fairly close to one another. The one on the left is Saturn – the slightly dimmer (and bluer) one is one of our guidepost stars, Spica. Wait until July 15 and you’ll see  the first quarter Moon so close to Spica it may drown it out  making the star difficult to see, except with binoculars – and the next night a slightly brighter Moon will be beneath Saturn. But any night this month the chart below will serve as a general guide – just understand the Moon is only in the vicinity for a few days near the middle of the month.

Click chart for a larger view. (Prepared from Starry Nights Pro screen shot.)

Click chart for a larger view. (Prepared from Starry Nights Pro screen shot.)

To learn when to wave  and smile for Cassini’s camera, get all the details of this historic space picture here.

Saturn is the most eye-popping object you can turn a small telescope towards  – but to the naked eye and binoculars it  looks pretty much like any bright star. But any small telescope delivering 30X or more should reveal its rings, however.

Color me red, yellow and blue!

Meanwhile, you might pick a moonless night – or one earlier in the month when the Moon is not so bright and well over in the west – and this will be a great time to test your color vision as well. The three bright guidepost stars in the chart above are very different in color. Antares is quite red, Arcturus is orange/yellow, and Spica is one of the bluest stars you’ll ever hope to see. Look at them and compare the color – don’t expect it to jump out at you. Star colors are better described as tints in my opinion – but with these three examples I think most people will see them.

For a complete description of star color and a helpful color chart, go here. The spectral type of our three stars is: Arcturus, K1; Antares, M1; and Spica B1.

Venus a constant evening star

If you have a clear and unobstructed horizon Venus should pop into view about 30-45 minutes after sunset, a fist or less above the horizon. At that time you might spot the other named stars in our chart with binoculars.  (Ckick for larger image. Chart prepared from Starry Nights Pro screenshot.)

If you have a clear and unobstructed western horizon Venus should pop into view about 30-45 minutes after sunset, a fist or less above the horizon. At that time you might spot the other named stars in our chart with binoculars. The sun will have set to the north of Venus, roughly where you see Pollux on the chart.  (Ckick for larger image. Chart prepared from Starry Nights Pro screenshot.)

Venus is a constant “evening star” during July 2013, low on the western horizon about half an hour after sunset and shining at a pretty steady magnitude  -3.9 – brilliant when compared to other planets and stars, but a bit dim for Venus.

In the course of the month as the time of sunset changes and the stars appear to slide past it and vanish, Venus seems to stay put except for a slow southward drift. It starts the month about 18 degrees north of west – but south of  where the sun sets – and concludes the month nearly due west – well, two degrees north of it as seem from my latitude of 41° 31′ North.

On July 9, 10, and 11 a fairly large crescent Moon sneaks by to the south of Venus and on the July 22, 2013  it has a real close encounter with first magnitude Regulus. They should make an interesting double star in  binoculars, barely a degree apart.

It will also be interesting to see how easy it is to pick out Regulus which will be competing with the twilight glow, as well as the much brighter Venus. I’m sure it will be easy in binoculars – but with the naked eye? Well, wait and see.

Saturn (magnitude 0.59) and Kappa Virginis (magnitude 4.15) make a similar pair of kissing cousins staying within less than a degree of one another all month. Again, binoculars may  be needed to see the star since Saturn is so relatively bright. In both cases we have separation of  4-plus magnitudes and  a degree or less.

Compare this to the classic double Mizar and Alcor – the middle star in the handle of the big Dipper. Good eyesight can separate this “horse and rider” pair, but for me it takes binoculars. With those two the separation is much smaller – about 11 minutes of arc  – roughly one fifth of a degree – but the difference in magnitude is a bit less than 2.  Bottom line – I’m sure good eyes will be able to separate the two pair mentioned – I’m not at all sure my eyes will  – though I look forward to a nice view with binoculars 😉

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