Hey, Vega, Nice To See Ya’

A linear band of cloud (not a contrail) bisects last night’s full moon shortly after moonrise. Bob King

Every moonrise is different. Last night’s Full Flower Moon rose squat and orange like you’d expect. But about 2 minutes later it ascended through a pencil-like layer of cloud. To the naked eye it looked exactly as if someone had taken a black magic marker and neatly drew a straight line across the moon’s face. No two snowflakes match, and I’d argue the same for every moonrise. Is anything really identical to anything else except at the molecular level?

Vega pokes out from behind a spruce tree during a display of northern lights. Bob King

Pretty as it is get ready to bid the moon farewell. It’s moving south in the sky toward its low point in Sagittarius. For mid-northern latitudes that means it rises more than an hour later each night. Tonight’s less-than-full moon returns near the end of evening twilight. By Saturday we’ll have an hour of dark skies before the next moonrise. Use that time to get reacquainted with one of the brightest stars of the late spring and summer sky — Vega.

I’ve been watching it “leave the nest” and rise ever higher in the northeastern sky over the past couple weeks. Vega is nicely placed for viewing starting around 9:30 – 10 o’clock local time. Just face to the east-northeast, hold you balled (vertical) fist at arm’s length and measure about two fists up from the horizon. The singular, bright, white star you’ll see is Vega, pronounced  as either VAY-guh or VEE-guh. It’s the 5th brightest star in the sky and the head luminary of the faint but distinctive constellation Lyra the harp.

Watch for shiny, white Vega in the northeastern sky after the end of evening twilight. It’s about 20° or two fists high around 10 p.m. Two easy asterisms — the Lozenge and Keystone — are found a fist and half to the upper left and upper right of the star, respectively. Stellarium

Located just 25 light years from the Earth Vega is also one of the closest bright stars. When you see it tonight the light that excites your retinal cells left the star in 1995 when the world seemed a more innocent place. Vega is similar to the sun in that it fuses hydrogen atoms in its core to create energy, but it’s hotter, more luminous (36 times as bright as our star) and 2.3 times as massive … and only 400 millions years old. 10 times younger the the sun — ah, youth!

Vega is about 400 million years old and hotter and larger than the sun. It also rotates so rapidly it’s oval shaped. From our point of view on Earth, we stare straight down over one of the star’s poles. R.J. Hall

Curiously, we view Vega pole-on. That is, it’s pole points almost directly toward the Earth. Vega spins incredibly fast — about 972,000 miles per hour (270 km/sec) or 219 times the speed of the sun at its equator. Because gases flex and flow Vega’s rapid spin has shaped it into an egg.

Four stars below Vega and one to its left form an imaginary harp, the reason why Vega is also known as the Harp Star. Once you spot Vega you can use it to locate two easy asterisms called the Lozenge and the Keystone. Asterisms are bright patterns of stars within a constellation that have a distinctive shape and are easy to find. The Lozenge belongs to Draco the dragon and the Keystone to Hercules. When learning new constellations it’s most helpful to start with a bright star, then an asterism and finally the constellation itself. We’ll explore both Hercules and Draco in the coming weeks.

7 Responses

  1. BCstargazer

    Vega, Deneb and Altair, the summer triangle were a great clear pre-dawn
    sky sight as I waited for the ISS to pass overhead. ALSO Jupiter and Saturn finally appearing above the mountain ridge to the south east will make a great target once Luna wanes a little
    Thank you Bob
    🙂

  2. Edward M Boll

    Always nice to see the bright stars emerge. Arcturus, Orion, the Pleaides and the Big Dipper have a reference mentioned of them in biblical writings more than 4000 years ago. Regarding Swan, I’m now ready to take a glance. At mag 5.5, I hope that it brightens some yet.

  3. Edward M Boll

    I don’t like to report bad news and I hope that this is premature but the most recent sightings of Swan have put it near magnitude 6.

  4. Edward M Boll

    Bob, this is almost laughable. These comets keep surprising is. As Comet Swan seems now to be fading. Terry Lovejoy said that there has been a notable brightening in Y4 the last 4 nights.

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