Night skies get shorter as the days get longer

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Astronomy column

Dr. Rolly Chiasson
 
Hi sky colleagues, It’s your sky guy. I’m back. I missed a month during the holiday season, but now it’s back to business – and sky pleasures.

Each month, I try to review what’s in the night sky for the coming month, and discuss some interesting astronomical topic.

Let’s look at the sky first. As I’m sure you’ve noted, the hours of light each day are increasing. The “day” is longer. But it’s not just increasing, it’s doing so by a greater amount each day so that by the first day of spring, the light or day hours are increasing by about four minutes each day. Then the amount of change begins to slow until the first day of summer – the “longest day”. Then the amount of daylight starts to decrease – faster and faster until by the first day of autumn, when it’s lessening by about four minutes a day. Then the decrease in hours of light starts to slow until we reach the first day of winter – “the shortest day”. Then the cycle repeats.

You will note that I’ve placed quotes around “longest” and “shortest”. In reality the 10 days before and after each one have just about the same amount of sunlight, although the sunrise and sunset times do change.

So what’s in our shortening night sky in February? Jupiter, as so often, is the king. As night falls, it is already well up in the southeast. As February begins, it’s highest around 10 p.m. and around 8 p.m. as February ends. While bright it’s beginning to get a little dimmer and slowly but surely, begins to set sooner.

At sunset Mercury is up in the west southwest and is so for the first few days of February. Then it begins to dim and fade into the sunset.

Mars – the Red Planet rises around 11 p.m. in the southeast and is high in the sky at dawn. By the month’s end it rises at about 9:30 p.m. Is it bright? Relatively, but you do need a current sky map (try Sky News magazine) to find it.

Saturn, as usual, rises in the southeast at about 1:30 a.m. and is well up by dawn. It’s not yet very spectacular, and of course you need a telescope to see its rings.

What’s left? Well, Venus  and it’s indeed dazzling. It is maximally bright in mid February but it only comes up or rises, two to two and a half hours before sunrise. If you want to get up, it’s beautiful and you can make a wish on it, just as when it’s the “evening star”.

Let’s try another subject for this month – the Zodiac. No, it’s not a military small boat! It is a circle of 12 30-degree divisions in the sky following the ecliptic. The ecliptic is the apparent path of the sun across our sky, over the course of one year. It’s not the path that the sun follows each day. For that matter, the planets and our moon follow roughly the same path.

While astronomy and astrology are very different topics, they both use the Zodiac. Historically, the 12 divisions are called Signs. The word Zodiac originally meant “Circle of Animals”, although certainly the Signs are not all animals – one being a sets of scales, one a maiden, one an archer, one a set of twins and one a water bearer.

While the Zodiac was originally named after constellations,

a)    The Signs were never the shape of the constellations

b)    While the Signs and positions originally lined up, over many centuries, the Signs and constellations no longer correspond to each other as to position.

Now, for astronomers, it’s a celestial co-ordinate system, while for astrologers, it helps them in their predictions of our fortunes or lives each day. Very different!

That’s it for another month. See you in 30 – or rather - 28.

 

Dr. Rolly Chiasson of Summerside is "Your Sky Guy."

 

Organizations: Sky News

Geographic location: Summerside

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