EDITOR’S NOTE: Ever wish for advance alert of an upcoming meteor shower/eclipse/etc. – and/or wonder “What’s that bright ‘star’ up there?” This should help. It’s our periodic feature by West Seattle’s own Solar System Ambassador Alice Enevoldsen, famed for her solstice/equinox sunset watches, among other things.
By Alice Enevoldsen
Special to West Seattle Blog
Happy summer, everyone! I, like many, did not enjoy our recent heat wave. I’m Seattleite to my bones, and temperatures outside 50-80°F send me searching desperately for relief. Lucky us, hot days make for comfortable stargazing nights. You’ll often hear me advocate for the winter skies, because they’re so pristine (whenever we can see the stars through the clouds), and the long nights give you lots of things to see. The benefit to summer skies is that you don’t have to bundle up, and you’re probably thrilled to spend an hour or two with an excuse to just relax in the cool night air, and we do (believe it or not) have more clear nights in summer.
Hey, what’s that?
Mars and Spica — This pair, a star and a planet, have been giving us quite a show every night in the West as soon as it begins to get dark, around 10 pm. If you’ve seen something in the sky and wondered what it was, I’m betting it is these two. Spica is a brilliant white, and Mars has a blush of a tan or salmon color to it.
You may be inexperienced at noticing the different colors of the stars, so this is a perfect chance to push yourself a little further. Go out tonight – if we get a break in the clouds – and look at this pairing. First, just try to decide if they appear to be the same color or different colors. Then, keep observing and start thinking about what you would name those two different colors. Try looking away at some other stars and then bringing your eyes back.
Another major difference to watch for in the pair is that Spica will twinkle, and Mars will not. Planets don’t twinkle (an easy way to remember this is that the song doesn’t go “Twinkle, twinkle little planet …”).
Twinkling is caused by the movement of air in the atmosphere — just like looking across a hot grill or warm pavement. Stars are so far away, they are just a pinpoint of light, and the moving air makes them seem to blink and change colors. Planets are closer, so although they look like just a pinpoint to your eye, they are in fact close enough to be a dot or a disc on the sky. Since we’re getting light from all sides of that disc, the moving air has much less effect.
I wish I had a photo of this conjunction here; maybe if you do, you can submit yours to WSB? You won’t need a very long exposure to catch the pairing, they’re bright and just after sunset so is the sky.
If I’m wrong, and you’re looking at something that isn’t a scintillating pair of objects, your “hey, what’s that?” may be the star Arcturus, a bit higher in the sky but still in the West, or the planet Saturn just about due Southwest. Over the course of the next month, Mars will travel across the sky away from Spica to make a beautiful pairing with Saturn in August.
Morning people? Venus is a brilliant morning “star” this month, rising shortly before the Sun in the East.
Looking for More
After you’ve noticed Mars, Spica, and Saturn, cast your gaze farther up, up, up for the Summer Triangle directly overhead. I know, I can hear you saying, “Alice, pick any three stars and you have a triangle, which one am I looking for?” Right, I know. These are three of the brightest stars in tonight’s sky, but they aren’t ones I’ve already mentioned: Vega, Deneb, and Altair.
Of the three, Altair is between South and East, about halfway up the sky. You’ll know you’ve found it because it is the middle star of a line of three, and it is the brightest of that line.
Vega is even higher in the sky in the same direction, and the brightest star in a tiny triangle.
Deneb will be the main challenge because although it is bright, it is the dimmest of the three and it’s right in the middle of the Milky Way. If you’re out camping, you can use Deneb and its constellation, Cygnus, as markers for the Milky Way itself. If you’re in West Seattle proper, it would probably take a widespread power-outage to be able to identify the Milky Way. These little power blips caused by birds short-circuiting the power lines aren’t large enough to dim the city glow enough to see a deep, dark sky.
August 11th — Perseid Meteor Shower pre-peak
August 12th — Perseid Meteor Shower true peak. You’ll be watching the Northeast between midnight and 3am.
August 17th — Autumn Equinox in Mars’s Northern Hemisphere! (Seasons are approximately twice as long on Mars)
Did I miss something? Please add it in the comments!
July 26, August 25, New Moon: the day of the new moon you won’t see the Moon at all, but in a few days before or after you might see a tiny sliver of a crescent Moon in the mid-day sky.
August 3, First Quarter: the first quarter moon is ideal for late afternoon and early evening observation.
August 10, Full Moon: The full moon rises at sunset, and sets at sunrise.
August 17, Last Quarter: the week around the last quarter moon, it is visible in the early morning sky.
Stellarium: Free planetarium software for your home computer. Bring up the sky for anywhere in the world – any time and date in history, or the future.
Clear Sky Chart: The astronomer’s forecast for the next couple days. Cloud cover, darkness, and “seeing” which is how nice it is to view the stars, all on one handy chart.
USNO: Dates and times of astronomical happenings.
Who is Alice?
Alice is many things and volunteers for a few different notable organizations, but the suggestions and opinions put forth in this article are her own and no one else’s. You can find more about astronomy at alicesastroinfo.com.