Watching the skies

The night sky always fills me with wonder, contemplating the distances involved, considering the journey each photon makes, from a hydrogen fusion reaction on a star light years away to my retina.

Screenshot, Stellarium

Screenshot, Stellarium

The weather doesn’t always cooperate and sometimes the light pollution makes it difficult to pick out feint objects, so a few years ago I started using Stellarium. Unlike other star charts, Stellarium is personalized to your exact position.  And perhaps the most incredible part is, it’s free.

Once you download the software, you input your location. This can be as simple as your town, or as precise as your latitude and longitude. Input your elevation and the default view (North, East etc.) and you will be shown the view as it exists. At one point, I matched the view on my screen to the view through my window, so I could look back and forth and identify objects.

The chart is in real time, so as the stars move in the sky they move on your screen. You can fast forward, reverse, and stop, allowing you to find any point in time. Know Jupiter is supposed to be visible tonight, and you’ll be looking around 2130? Fast forward to 2130 and find Jupiter, and you’ll know right where to look. You can also see satellite paths, so if you’re using binoculars you can plot when and where to look.

The features are incredible, allowing you to overlay constellation lines or pictures (A bear for Ursa Major and Minor) making it a nice teaching tool for family stargazing. Navigation is easy, you drag the view to turn or look at a different angle, zoom in and out with the scroll on your mouse. Click on an object for its name and info. One thing that takes a little getting used to is it is in real time, so when you zoom in to look at Messier 31, it will move across your screen, because the world is turning. Just click pause.

You can simulate light pollution to match whatever you’re dealing with, or you can look at a pristine sky to see whet you’re missing. I use it a lot on nights when it is cloudy or too cold to go out, or when there’s an alignment that will be happening when I’d rather be asleep. You can also change the location to get a feel for events that are not visible from where you are, or to match your location when you travel.

Did I mention that it’s free?

Another nice application, also free, is available from NASA. “Spot the Station” sends you an email (or text) with the coordinates for the next flyover of the International Space Station. A typical email reads “Time: Sun Jan 12 5:31 AM, Visible: 3 min, Max Height: 63 degrees, Appears: NNE, Disappears: NE”, in this case the next morning at 0531, the station was visible for three minutes as it passed on a short arc reaching an altitude of 63° (straight up is 90º) traveling from North Northeast to Northeast. I’ve seen arcs that were anywhere from one to six minutes, typically pre-dawn or late evening. I usually get a preview on Stellarium to give myself a feel for which stars to orient with.

The International Space Station is about 260 miles from Earth. The average distance to Mars is 140 million miles, with the closest approach being 33.9 million miles. Jupiter gets as close as 390 million miles. The closest star (other than the Sun), Alpha Centauri, is 4.2 light years (24.6 trillion miles) away, but that can only be seen from the Southern hemisphere. Barnard’s star, the closest visible (with a telescope, it’s a red dwarf) star in the Northern hemisphere, is 5.9 light years away. That’s over 34 trillion miles, or more precisely 34,683,890,693,365 miles, or 133,399,579,589 times as far away as the International Space Station.

Some people look at the sky and see pretty lights. I see the universe, and the perspective of our place within the universe. One pretty light among billions.


2 comments on “Watching the skies

  1. MIke R says:

    I’ve not tried Stellarium on my computer but I use it on my iPhone. It is far to polluted in the Central Valley of California to see the sky much but when I am in the Sierra Mountains it helps me orient to what I am looking at, right away. When I think of how I struggled as a boy scout to understand the stars, with nothing but a book and a compass . . . .


  2. I loved this!! Star gazing is one of my favourite things to do!!


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