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Keeping it
Curious

The GRPM Blog

Winter Stargazing!

Date

December 17, 2020

Category

Orion Nebula

The Stars are Coming to Life in West Michigan.

Winter offers some of the most exciting sights for a stargazer in West Michigan. For astronomers in the area, winter stargazing is often much more rewarding than summer. Of course, you have to be willing to bundle up and spend time outside in winter in the middle of the night, but if you are curious and the weather cooperates, an adventure awaits! 

The Greatest Conjunction.

In astronomy, a conjunction is when two planets appear close together in the sky. A conjunction of Jupiter and Saturn only occurs every 19.6 years, and the next conjunction will take place on December 21 this year.  This will be the closest Great Conjunction since 1623 when Galileo, the first person to point a telescope at the sky, was still alive.

Stargazers who are fortunate enough to see this year’s event, will be a part of a historically important time for astronomy. If you are stargazing in West Michigan, Jupiter and Saturn will be too low to our horizon to easily see the conjunction, but stargazers located at lower latitudes will have the best chance to view.

However, you can still go outside until December 21 to watch the progress of Jupiter and Saturn. Every night, Jupiter and Saturn will inch closer and closer together. In fact, it will be possible to see both planets and their moons in the same telescope field of view! 

Spectacular Winter Stars.

Now let’s explore the Winter Circle, a collection of constellations currently visible to the southeast after sunset.

The constellation Orion the Hunter is the key to the Winter Circle. Orion is one of the most recognizable constellations consisting of bright stars in an instantly recognizable pattern. If you can find three stars in a row, that is Orion’s belt. On one side of the belt is the bright red supergiant Betelguese (beetle-guys), and on the other side, the bright blue supergiant Rigel.

Just below the belt is a cluster of faint, blurry stars. The blurriness, which astronomers call “nebulosity” is the Great Orion Nebula. The Orion Nebula is best viewed through a telescope where one can see a vast cloud of gas illuminated by the stars within it.

A novice stargazer can use Orion’s belt to direct them toward other constellations. To roughly follow the belt to the east we can find Sirius in Canis Major. It doesn’t line up exactly, but it is easy to find because Sirius is the brightest star in our night sky. To follow the belt to the east, we can spot the bright red star Aldeberan, another red supergiant. Aldeberan is the eye of Taurus the Bull. In the shoulder of the bull, you have the Pleiades star cluster. The Pleiades cluster is best viewed through binoculars that allow you to see the close group of bright blue stars.

Over the head of Orion, you can find a circular constellation Auriga the Charioteer with the bright star Capella. Nearby is the constellation Gemini which looks like two stick figures holding hands. In Gemini, you can find the twin stars Pollux and Castor. Canis Minor isn’t very recognizable as a dog, but the bright star Procyon (pro-sion) is easy to spot.

Winter Constellations
Source: Stellarium, 12/16/20 at 7:00pm. Jupiter and Saturn are already very low to the southwest. Also in the screenshot, you can see the Summer Triangle which will set earlier in the west each night.

Why Winter?

The winter sky offers some of the most rewarding sights for a backyard stargazer for two main reasons:

The air is less humid in the winter time, making the stars appear brighter than in the summer. Cold air holds less moisture than warm air, which is why you can find dew on the grass after a cool fall night. The water molecules in humid air absorbs and scatters light — especially red light — making the stars dimmer. Humidity in the Earth’s atmosphere is a nightmare for astronomers and West Michigan is a fairly humid place. Even if you have a night without cloud cover, humidity can cause problems for astronomers.

Many of the most impressive astronomical sights are visible in the evening sky during the winter because of where our solar system is located in relation to other stars in our galaxy. At the GRPM’s Chaffee Planetarium, the staff often share how the Earth’s yearly movement around the sun points Earth in different directions of space. During winter in the northern hemisphere, western Michigan is pointed at an area of space which, by chance, has bright astronomical objects which are relatively close to the Earth.

These impressive sights include the most visible nebula – the Great Orion Nebula, the brightest star in the sky – Sirius, and the Pleiades star cluster – the most visible of its kind.

The winter sky also includes a few more bright stars which are close to us, including the brightest star in the night sky, Sirius. Only 8.6 light years away, Sirius is one of the closest stars to our Sun, while also being a large main sequence star (about twice the size of our Sun and 25 times more luminous). An interesting side note, Sirius will approach closer to our Sun over the next 60,000 years, making it even brighter for a patient astronomer.

In the same direction, we will see Procyon, also a bright and close star at about 12 light years away. There is also the Orion Nebula which is further away at 1,500 light years but that is still the closest large region of star formation. In fact, the Orion Nebula is faintly visible to the naked eye.

If you have ever looked up at the winter stars and thought they seemed somehow brighter or more magical, you were right. Winter in West Michigan offers a view of some of the most dynamic sights astronomy can offer. By learning the constellations of the Winter Circle, you can explore these sights for years to come.

Happy stargazing!

By: Jack Daleske, the GRPM’s Planetarium Manager

Cover image source: NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team

Carousel Update.

The Spillman Carousel is currently closed while we are undergoing riverfront construction. The Carousel will re-open Spring of 2025.

Carousel Update.

The Spillman Carousel is currently closed while we are undergoing riverfront construction. The Carousel will re-open Spring of 2025.

Carousel Update

The 1928 Spillman Carousel is closed while we undergo riverfront construction. The carousel will re-open in the Spring of 2025.