Steve’s Virtual Planet

Stellarium planetarium software

Over the last decade or so, the internet has brought forth many great resources for the hobby of astronomy. Amongst the many pieces of free software I have found, one of the most useful is Stellarium, a downloadable “planetarium” program. Stellarium runs on Windows, Mac and even Linux and gives you a view of the sky that easy to configure and use. Sometimes, just the basic features are all you need and version 10 of Stellarium is perfect for use in the field for astronomy outreach or just showing a simple view of the sky to your friends.

Well, as with many things, the best gets even better. Stellarium version 11 is out and a new stable version has just been announced this month. You start at the Stellarium website and download the program, then install it. The new version still has the same look and feel to version 10, however, its worth working through the list of features on their web site.

I am not going to be able to do a full review of the program in this article, but I still highly recommend the program. The interface is not what you may typically find in Windows programs, but this tool is more universal than what our GUI friends might call “standard”. Nevertheless, take the time to explore the screen once you’ve installed it. And dig into the help feature to see what the mouse and keyboard shortcuts are. Admittedly, this program is a bit of a challenge to get used to but it’s not a very complex interface.

The help screen now has hyperlinks that take you to the documentation wiki, where you can get the full user’s guide. The documentation was there before, but now it’s much easier to get to it from the program. You just have to have a live internet connection when you use it.

Stellarium is a great example of how people get together in hyperspace and create and support a great product. Consider downloading and using this resource for your astronomy outreach and even your personal enjoyment.

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SVC Tip #4 - Going in circles with the Big Dipper

The northern sky has several memorable asterisms and the favorite one is probably the Big Dipper. It’s actually only part of Ursa Major, the Great Bear. It’s easy to spot when it swings into view in the early evening this time of year. And the further you are to the north when observing, the better the view will be.

The Big Dipper will contain stars which will be visible at some time on most nights. As those stars move counterclockwise around the northern polar star Polaris, they are said to be “circumpolar”. In other words, if we are at a certain minimum latitude (around 41 degrees), a specific star in the dipper will make a great circle in the sky and never go below the horizon.

Of course, around the suburbs you might be dealing with the tree line but not to worry. You can plan for this using Sky View Cafe (SVC) and on of its options on the Sky tab - the Horizon to Zenith view. Look for the list of options over on the right hand side when using the Sky tab. The first option is probably set to a full sky view, but click the don arrow to list the others and choose Horizon to Zenith. Then, look for the “Select a direction …” button near the Insolation tab and change it to N, for north.

Now you’re looking at a full slice of the northern sky from the horizon to the zenith. By adjusting the time and date values up in the time field, you can preview what your view of the dippers will be. If you also mark the names of the stars for the constellations, you can refer to the chart made in the previous blog on the dippers. And remember, you can print from Sky View Cafe and get a simple chart to use in the field for the exact time and date you’ve selected.

Have a great time with SVC and check out the other tips here SVC Tip #1 & SVC Tip #2 & SVC Tip #3.

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Gauging the sky with the Great Dippers

This time of year is a great time to reconnect with The Big Dipper in Ursa Major and it’s cousin the Little Dipper, in Ursa Minor. Even though Daylight Savings Time is going push dusk well into the evening, you will still be able to follow these great asterisms into early night as they climb over the trees.

As twilight progresses after sunset, the individual stars of the celestial bears gradually come into view. The brighter stars appear first of course, but the main stars in the Big Dipper are within a fairly small range of magnitude - about 1.8 down to about 2.4. In order of magnitude, you have Dubhe, Alioth, Alkaid, Mizor, Merak, Phecda. Megrez, where the handle connects to the bowl is 3.3 magnitude, but still bright enough to catch in suburban skies.

If you can see all of the Big Dipper, then you should be able to easily see Polaris at the end of the Little Dipper. It’s the brightest star in the constellation. You will also be able to see the end of the bowl of the dipper and the next brightest stars Kochab and Pherkad. The remaining stars are dimmer than 4.3 magnitude so they are much dimmer than most suburban nights will allow. But you never know your luck!

If you create a chart with these two constellations and write in the magnitudes, you will have a very useful reference to use to gauge the sky. Wikipedia has good information on all the constellations and the Celestial Bears are no exception. Follow the links below to get a lists of these stars with their magnitudes and charts that you can print to make a field reference - Big Dipper & Little Dipper. As with all the Wikipedia constellations pages, there’s also a lot of detail on the mythology and star lore of the heavens.

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Phases of Venus

The skies this winter are graced by the closest and yet perhaps the most enigmatic object beside our moon. Venus has been sparkling in the western sky now for weeks. Our nearest planet has a number of mysteries associated with it - it’s cloud cover and it’s sulfuric acid atmosphere and a surface corroded past any terrestrial warranty of any kind. But perhaps Venus’ most wondrous mystery is the characteristic of the bright planet right in front of our very eyes - it’s phases.

We marvel now at this jewel of the evening sky (sometimes in the morning). For centuries, people of planet Earth have worshiped Venus as a Goddess in her many guises.  But until 1610, when Galileo peered through his modest telescope, the entire human race was ignorant of her changing face as she drifts around the Sun. When we look closely at our sister planet, with a little bit of magnification, we get to see that Venus goes through phases, very much like our moon. This is what Galileo saw in 1610 and the result of his observations essentially clinched the argument for the Copernican Hiliocentric theory.

For us mere mortals, we can simply aim a small telescope up at Venus and enjoy it for ourselves. As of this writing, Venus is about 60 percent full or basically still a gibbous shape. Venus reaches half phase around March 28th. As the planet comes around in its orbit over the next few weeks, that shape will steadily work it’s way into a crescent shape that grows ever thinner. By late May, this crescent gets very thin and by early June, the planet is too close to the Sun for safe observation. Shortly after this time, she becomes the “morning star” once again, emerging ahead of the sun in the pre-dawn morning light.

Take some time to get to know our sister in the sky. Check these links below for more details on the phases of Venus. Wikipedia Venus & Wikipedia Galileo

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SVC Tip #3 - Planets and trees

This season, the planets are coming around into view again in the evening sky. But, what about trees in the title of this blog? Ahh, if you’re viewing from the suburbs, trees tend to get in the way of objects only a short angular distance from the horizon. The point is that your plans for planet watching need to take your neighborhood tress into account. The tree line will be a factor in determining when your best line of sight will give you access to any of the planets.

Here is a great reason to use one of several interactive planetarium tools to give you a view of the sky you can plan for. My favorite is Sky View Cafe (SVC). (see the other tips here SVC Tip #1 & SVC Tip #2). With Sky View Cafe, you can set your time and date and check in advance how the night’s sky will progress. You can move the time forward and backward to see where the planets will be. And by hovering the mouse pointer over the object, you will see the coordinates in the info band at the bottom. In the case of planets, right ascension and declination aren’t really useful since the planets are drifting across the background of stars. But the altitude and azimuth are very helpful because you can predict where to look for the planets in relation to the horizon and any trees in your viewing site.

Use the azimuth and altitude values of your target and compare with the height of the treeline in that part of the sky. Tweak the time settings to get your target planet in a portion of the sky that is easily viewable. You can even print a sky map from SVC and use that to make an observing plan. Then you can even go one step further and measure the height of the treeline in degrees altitude every 15 degrees of azimuth and make a plot on a circle the same size as the SVC printout. That becomes your reference to use when picking the best time for viewing any object.

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The Winter Hexagon

The shortened days of the winter months grant an extra chance to get out under the stars. Even with cold weather forcing star gazers to “rug up”, there are at least several objects that appear soon enough such that you don’t have to brave the chill for too long into the night. A great circle of stars known as the Winter Hexagon appears overhead in the early evening forming a ring connecting a grand collection of constellations.

Starting with Sirius, the brightest star in the heavens, we can work around counter clockwise to Rigel, Aldebaran, Capella, Pollux, and Procyon. The circuit takes in Canis Major, Orion, Taurus, Auriga, Gemini and Canis Minor.

These stars range in magnitude from -1.5 with Sirius down to Pollux at mag 1.1. So, they are peeping out early and high overhead this time of year. As the night deepens, one can easily make out the figure of Orion, easily spotted by it’s belt of three stars. The ring of Auriga is usually next to become clear, forming it’s own circle of stars. The triangle of the face of Taurus slowly takes shape as the great expanse of the Big Dog about Sirius moves up into the southern sky like a big meat cleaver.

All these objects shine through even moderate light pollution. So, whether you’re in the suburbs or the country, you can practice your geometry using these fine beacons of the winter night.

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More on Astronomy Outreach

Many of us in the Atlanta Astronomy Club have found a real calling in sharing our love of science and astronomy with the public. And at dozens of events through the year, we do what we can to enrich the lives of people through our love of this activity. A little over a year ago, I received the first and second level award for astronomy outreach from the Astronomical League, the Outreach and Stellar Outreach.

Astronomical League Award 2009

The previous award was an accumulation of 60 hours logged in 2009. Most of these hours were from my observatory sessions at Fernbank Science Center. There were several outreach events with the Atlanta Astronomy Club as well. Well now, after an additional two years of volunteering at the Fernbank Observatory, I have accumulated an additional 250 hours of logged time. This should qualify me the Astronomical Leagues Master level Outreach Award for which I am submitting my application.

My hope is to update this post very soon with an update.

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Jupiter’s Back

This past couple of months have granted some great views of Jupiter. We’ve had better seeing than normal the preceding two months in the Atlanta area. I had two exceptional views of the GRS through the Fernbank 36 inch on December 1st and 8th.

When I drew a bead on Jupiter early that first night, I couldn’t believe the seeing had improved that much from the week before. I kept looking, looking, and sure enough, it was crisp, more detailed than most nights. In the suburbs already! Early on, the GRS was coming around the east and it was already looking distinct, if not fully visible. By 9:00, it was going to be right on the meridian. And boy was it ever there! Not very bold in color but a very distinct football shaped outline. The boundary of the oval was very crisp.

We had a fairly big crowd at the observatory that night, well over 120 people. I felt like a kid at Christmas announcing to the visitors, many of them students, that this was a treat! And the seeing just kept up. I couldn’t believe we had such a sustained steady sky that evening. That kind of view registers almost permanently and you just don’t forget it for a while. What a nice memory!

In any case, there are still plenty of days left to catch Jupiter this apparition. And you get some extra dark hours when daylight savings time kicks in on March 11. Jupiter will rise back up 15 degrees at the same time the next evening and give you a double bonus with Venus right next to it! Our largest planetary neighbor will hang around through most of March.

Have fun with Jupiter and good luck hunting the GRS!!

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Spring 2012 Class - Astronomy in the Suburbs

I am very pleased to announce that I have gotten the approval to teach an astronomy class again at Emory Center for Lifelong Learning this coming March. This is a four week, two hour each Tuesday evening session under the title “Astronomy in the Suburbs - An Introduction to Stargazing”.

The class ran this past October for the first time and I am very pleased with how it went the first time. My students also thought it was a very informative class. Class material was largely from my own experiences doing sidewalk astronomy and public viewings at Fernbank Science Center. But, I also poured in quite a few tips I’ve developed from my own private viewing and star parties with the Atlanta Astronomy Club.

I will be adding information to this site over the next two months related to the course. If you are interested in attending or know someone that may want to take such a class, visit Emory Center for Lifelong Learning. There is a charge for this class from Emory and I cannot provide any discounts. But I think it still good value as these classes go and you’ll be well prepared by the end!

Here’s the link to the class information and handy sign up button. If you wish to write me directly with questions about the class, send me an email.

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Winter targets sans planets

These last few weeks have seen the gradual westward track of Jupiter. In the evening hours, Venus has been working it’s way easterly. They are always fun to explore. But the evening are much longer now, so, why not work on finding nice objects to look at once the planets have been thoroughly checked out. Hmmm, what to do!?!?

Well, check the Messier list first. A few choices there. And maybe a planetary nebula or two. Check. Galaxies? not much right now. How ’bout stars with color. Yep. Several of those to enjoy. Of course, there’s always the standby - double stars! You never run out of them. So, here goes.

First, the Messier objects - M79, the only globular up right now; M81, one of the few galaxies you can catch in suburban skies; M36, M37, M38 in Auriga, good wide angle objects for binoculars or low power scopes; M45, The Pleiades and the Hyades too, great wide open clusters that look good even in 7 power binoculars; And don’t forget M42, The Orion Nebula.

There’s Caldwell 59 (or NGC3242), The Ghost of Jupiter, a nice planetary in Hydra, about 30 degress south of Regulus. For colorful objects, there Hind’s Crimson Star, a very red carbon variable star about 8 degrees below Rigel; there’s also Betelgeuse, obviously orange at just about any magnification.

Finally for doubles, there’s Castor, Rigel, Mintaka, Alcor/Mizar, Algieba. Since winter time brings longer nights, you might as well hop around and visit some of these charmers. Whether they are old favorites or your catching up for the first time, they are all easy enough to catch even with a small scope and in suburban skies.

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