Good morning, Orion! – Sky & Telescope

August 14, 2019 - Comment

An August jaunt at daybreak reacquaints us with the harbinger of winter. Orion mounts the southeastern sky at daybreak on an early September morning. Bob King If Orion’s rising and also you’re watching it in shirtsleeves, life is nice. Mercury, the Perseids, and the lure of morning comets tugged at me to remain awake till


An August jaunt at daybreak reacquaints us with the harbinger of winter.

First light

Orion mounts the southeastern sky at daybreak on an early September morning.
Bob King

If Orion’s rising and also you’re watching it in shirtsleeves, life is nice. Mercury, the Perseids, and the lure of morning comets tugged at me to remain awake till daybreak this previous week to see the Hunter attain a leg over the jap horizon. Orion, a constellation usually related to chattering enamel and biting winds for Northern Hemisphere skywatchers, returns to view throughout the canine days of summer season after we want it most.

Orion’s wintertime associations imbue its arrival with a “cooling impact” after weeks of warmth and humidity. I laughed once I stepped out the door at three o’clock the opposite morning, regarded up, and noticed that Cassiopeia may additionally play that recreation. It lastly hit me that W is the primary letter within the phrase winter. In fact.

Dawn struggle

Orion, the Hunter, climbs from the horizon haze over Lake Superior in Duluth, Minnesota, throughout morning twilight on August eight, 2019.
Bob King

I drove to a seaside on Lake Superior and sprawled out on a mattress of pebbles, the rounded stays of 1.1 billion-year-old magma that erupted lengthy earlier than the celebs of Orion had even organized right into a constellation. One after the other the Hunter’s patterned stars rose from the horizon haze because the Earth turned. First his defend, then by-and-by, Bellatrix, Betelgeuse, the Belt, and Rigel in that order. Bellatrix briefly outshone brighter Betelgeuse by dint of upper altitude and lessened atmospheric extinction, the dimming of a star attributable to low altitude haze. Not 10 minutes later the purple supergiant had regained the higher hand.

Through the years I have been requested why sure constellations are solely seen throughout sure seasons. A typical query is why we will not see Orion within the summertime.

Seasonal swing

In December and the winter months, Orion and Earth are on the identical facet of the Solar. Like a planet at opposition, Orion rises shortly after sundown and shines all evening lengthy. Six months later in June, our line of sight (arrow) to Orion additionally contains the Solar, so the constellation is misplaced within the glare of the daytime sky.
Bob King

Drawing circles within the air, we clarify that Earth’s orbital movement makes the Solar seem to maneuver throughout the sky day-to-day, week-to-week, and month-to-month. Each August the Solar slides eastward from the constellation Most cancers into Leo, the Lion. No matter constellation the Solar is close to is invisible — misplaced within the glare of daylight. Orion was misplaced in that glare throughout Might, June, and July as a result of the Solar shone from Taurus and Gemini, constellations not removed from the Hunter.

Move over, sun

(Left): In June the Solar shines from the identical a part of the sky as Orion so we are able to’t see the constellation. Proper: As soon as the Solar has moved away — attributable to Earth’s yearly orbital movement — Orion turns into seen at daybreak in August.
Stellarium

Earth has since moved alongside its orbit, shifting the Solar into Most cancers, the Crab, far sufficient away from winter’s signature constellation that it might roam free once more within the pale darkish of daybreak. Because the Solar continues to maneuver eastward and out of the best way, Orion will climb larger and better till it is seen in complete darkness earlier than daybreak (September) after which evenings (November).

I like seeing Orion whereas listening to the stridulations of katydids and lap of the waves earlier than the sting of frozen fingers. The soonest I’ve sighted its return was this previous July 30th when two-thirds of the well-known determine rose from the chilliness waters of Lake Superior in a brightening sky. The Belt, pitched nearly vertically, recalled a rope with frequently spaced knots for climbing. Binoculars gave one of the best view.

Cutting Orion with a polar knife

Orion loses its belt on the North Pole as a result of all three of its stars are under the celestial equator, which on the pole, defines the 360° of horizon. On the South Pole Orion retains his belt — barely — however loses his head!
Stellarium

From my 47° N latitude the Belt tilts westward on rising, however from ~35° N latitude (Albuquerque, Oklahoma Metropolis) it ascends vertically in relation to the horizon. Curiously, the Belt is invisible from the North Pole, its northernmost star, Mintaka, with a declination of –zero° 18′, stays simply out of attain, about ¼° under the horizon. In the meantime, observers on the South Pole can see the well-known asterism for months on finish very near the northern horizon throughout polar winter. It might appear apparent however north is the one course you may look from the pole. East and west are meaningless. Irrespective of which “course” you face you are all the time wanting north. Equally, all is south from the North Pole. No star rises, no star units. The paths of all celestial objects are parallel to the horizon.

It will get weirder. Journey only a brief distance from both pole and east and west all of a sudden materialize. The rising, end result, and setting of the celebs provides course to all factors alongside the horizon.

Humorous how the thoughts drifts whereas watching Orion rise star by star. That is among the best issues about being a skywatcher — you are all the time alongside for the journey.



Supply hyperlink

Comments

Comments are disabled for this post.