Jan 31

What’s Up in the Sky

What’s Up in the Sky – February, 2021

What’s Up With Betelgeuse?

Last month we focused on one of the most prominent and popular constellations, Orion. Now, as if bright nebulae, stars of all sizes and colors, and a sword and belt recognizable by all weren’t enough, Orion’s brightest and most famous (they named a movie after it) star, Betelgeuse, is once again in the news.

Most readers are familiar with Betelgeuse and its position as Orion’s right shoulder as well as its reddish color (hence the designation, “red giant”). Some might even be aware that the star’s brightness varies periodically over a span of 420 days and this is what made some headlines in January and February of 2020. During that time the drop in brightness was 50% greater than the previous year, making the star appear noticeably dimmer. And astronomers both amateur and professional did take notice. In fact, amateurs are the main source of variable star data and they were astonished as well as being jolted into action.

Since the first observations, scientists have been collecting a plethora of data of all types in order to understand the causes of the star’s dimming. The two main theories are: a rapid increase in new dust in the star’s outer shell, or a rare drop in the temperature of its surface. There were some questions about the possibility of the star going supernova and astronomers aren’t certain about that. Chances are pretty good that it won’t be in our lifetimes.

One thing that is certain this month is that some of the best stars and constellations for observing will be visible, assuming clear skies, and Orion is right in the middle of it all. Find Orion’s belt and follow it down and to the left where you will spot Sirius, the most brilliant star in our sky. Known as the Dog Star, it lies in the constellation Canis Major, the Big Dog. Above and to the left of Sirius is the star Procyon (PRO-see-on) in the constellation Canis Minor, the Little Dog. Procyon and Sirius are known as Orion’s hunting dogs. You’ll notice that Canis Minor consists of only two visible stars. Think of them as the dog’s tail. Procyon, Sirius, and Betelgeuse form the Winter Triangle, which needs no further explanation.

This area is also the home of the Winter Hexagon formed by the stars Sirius, Procyon, Castor and Pollux, Capella, Aldebaran, Rigel and back to Sirius. It also contains nine of the 15 brightest stars visible from our latitude north. Observe the Winter Triangle from a dark location and you will see that the Winter Milky Way flows between Sirius and Procyon and just above Betelgeuse.

So whether you use your naked eye, binoculars or a small telescope, there’s much to enjoy up in the sky.

This month in history:

Feb 1: Shuttle Columbia breaks apart during reentry killing all 7 astronauts – 2003
Feb 7: First untethered spacewalk made by Bruce McCandless – 1984
Feb 14: Voyager 1 looks back to take photo of solar system – 1990
Feb 18: Pluto discovered – 1930
Feb 20: John Glenn is first American to orbit Earth – 1962
Feb 23: Light from supernova 1987a reaches Earth – 1987
Feb 24: Detection of first pulsar (by Jocelyn Bell in 1967) is announced – 1968

Jan 03

What’s Up in the Sky

What’s Up in the Sky – January, 2021

Welcome Back Winter Constellations

Most people probably don’t consider January to be a time for going out and enjoying the wintry sky. After all, it’s usually cold and cloudy and often snowing. But on those rare occasions when the sky is clear, it is definitely worth the effort to step outside and enjoy the sights that the sky has to offer.

Part of the reason is because some of the year’s most beautiful and interesting constellations and stars are in view, conveniently located, and out at convenient times. Let’s start with Orion, the Hunter, one of the most easily recognizable patterns in the sky. As with most sky observing, timing is important, but not critical. If you go out tonight right after dark, it will be a challenge because Orion will just be rising low near the eastern horizon, and won’t be easily visible until about nine o’clock. As the month progresses though, it rises earlier until, by the end of the month, not only Orion, but also his friends will be dominating the southern sky.

Two patterns of stars stand out when viewing the Hunter – the four bright stars that form his torso and the three stars lined up to form his belt. Take this opportunity to scan the belt and sword with binoculars. See if you can tell which of the sword “stars” is not really a star at all, and which one appears to be a double star.

The two most famous and easily recognizable stars in Orion are Betelgeuse and Rigel, upper left and lower right of the four that make up his body. Betelgeuse is a red giant star that, if located where our Sun is, would extend out beyond Earth’s orbit. Rigel is a white giant 50 times bigger than the Sun. It will likely cool and expand and after tens of thousands of years until it too becomes a red giant.

Closer examination of the sword reveals that the middle “star” is actually the Great Orion Nebula, a complex and fascinating region of young, forming stars and glowing clouds of gas 20,000 times larger than our entire solar system. Embedded in the heart of the Great Nebula is the beautiful multiple star system known as the Trapezium, consisting of four hot young stars in a tight trapezoid-shaped cluster. Although the nebula itself is visible to the naked eye, you will need binoculars or a small telescope to see the Trapezium.

Just below the easternmost belt star lies a dark cloud of gas and dust silhouetted against a brighter region of glowing interstellar gas heated by the surrounding stars. Known as the Horsehead Nebula (it takes its name from its shape), its enormous size is almost beyond comprehension – you could fit a billion solar systems inside it. And the Horsehead is a tiny part of an even larger cloud that is only visible with the aid of large, specialized equipment. It is best seen by Googling online images.

So spend some time scanning Orion with binoculars and familiarizing yourself with this region of the sky. Next month I will guide you around Orion’s neighbors and visit nearby sights up in the sky.

This month in history:
Jan 1: Asteroid Ceres discovered by Giuseppe Piazzi – 1801
Jan 4: NASA cancels further production of Saturn V rockets – 1970
Jan 13: Galileo discovers Ganymede, moon of Jupiter – 1610
Jan 19: New Horizons spacecraft launched on its journey to Pluto – 2006
Jan 27: Apollo 1 astronauts Chaffee, White and Grissom die in fire in capsule – 1967
Jan 28: Seven astronauts killed when Space Shuttle Challenger explodes during launch – 1986

Dec 03

What’s Up in the Sky

What’s Up in the Sky – December, 2020

Planets Put on a Great Show
Although I often write about things that end up being hidden by clouds, this month offers a very good chance to witness a very rare sight.

If your gaze has drifted toward the southwestern evening sky lately, you have hopefully noticed the scene I described at the end of last month’s column, Jupiter shining brightly with faint Saturn to its upper left. Since Jupiter is the brightest thing in the sky that’s not the Moon, you may have missed Saturn, which appears only one tenth as bright. Hold two fingers at arm’s length. That’s how far apart the two planets appear to be.

And that’s the key, their separation. They look pretty close now, but by December 21, they will be so close together that a pencil at arm’s length won’t fit between them. Their pairing is the closest since 1623 and until another in 2080. Unfortunately, no one saw the 1623 event because the Sun was in the way and in 2080 you’ll have to get up before sunrise to see them.

That’s another reason to make an effort to observe the two giants, you will probably never have another chance, although teenagers stand a chance of being able to say they saw it twice sixty years from now. So again, each clear day at six o’clock, check out the southwestern sky for the “stars” of the show.

For those with a small telescope or binoculars (preferably on a tripod) be sure to observe the planets as close to December 21 as possible. When the planets are at their closest, they should both be visible together in a single field of view in such devices. For those with a smart phone, zoom in on the scene to view it in real time. Take it all in and enjoy it because you probably will never have another opportunity.

In addition to that celestial show, this month also has a meteor shower to offer. The night of Sunday, December 13th could be called the night of the shooting stars for on that night you’ll have an opportunity to witness the most reliable, prolific, and brightest annual meteor shower, the Geminids (showers are named after the constellation from which they appear to streak).

Not long ago, August’s Perseids were considered the top shower. But over the past few decades, the Geminids have intensified and are now in first place. Their popularity is hampered by the lousy weather that usually accompanies them.

But if the 13th does turn out to be clear, find a dark spot facing east, bundle up more than you think is necessary, break out the summer recliner, take along a thermos and an extra blanket or insulated sleeping bag and enjoy what’s up in the sky.

This month in history:
Dec 3: Pioneer 10 spacecraft makes closest approach to Jupiter – 1973
Dec 4: Mars Pathfinder is launched – 1996
Dec 11: Annie Jump Cannon is born – 1863
Dec 14: Gene Cernan, Apollo 17 astronaut, is last human to walk on Moon – 1972
Dec 16: Last two Saturn V moon rockets donated to museums – 1976
Dec 24: Apollo 8 astronauts give us inspirational moment from lunar orbit – 1968
Dec 25: Isaac Newton born – 1642

Nov 05

What’s Up in the Sky

What’s Up in the Sky – November, 2020

Spacecraft in the News and Planets in the Sky

I want to begin this month’s column with a brain teaser: What did OSIRIS-REx say after orbiting Bennu for a couple of years? Before you answer, you may need a little background.

OSIRIS-REx is a spacecraft that was launched by NASA in 2016 and has been in orbit around the asteroid Bennu since 2018, where it will remain until 2023. The actual name represented by the spacecraft’s initials is too long for this column, but it is basically a sample return mission. OSIRIS-REx has been studying the asteroid for two years and recently touched down briefly to collect some asteroid stuff before returning to orbit. It will remain in orbit around Bennu until 2023 at which time it will bring its asteroid sample back to Earth for us to study and enjoy.

This is not the first mission to bring stuff from space back to Earth, but it will be returning with the biggest and best sample to date. And the method used to collect the sample is imagination at its finest. At 200 million miles distant, the spacecraft is too far for real time commands so the entire orbit, descent, and collection sequence had to be pre-programmed. The meticulous planning for the sample collection was impressive and included orbiting the asteroid for two years while mapping and studying potential sites. The spacecraft then touched down for about five seconds, allowing the sampling arm to release a burst of nitrogen gas which stirred up rocks and soil that were captured in the sampler head. The collection was a great success and can be watched on YouTube. So the answer to the brain teaser mentioned earlier is, “Tag, you’re it”.

So what’s the big deal about asteroid dirt that would motivate NASA to devote many years and resources to the mission? First, asteroids are believed to be leftover remnants of the formation of the solar system that, unlike planets, have remained unchanged over the past several billion years. Second, they are relatively close and easy to get to. Third, there are lots of them so we have many targets from which to choose. Asteroids have also been the center of speculation regarding the possibility of mining them for useful minerals.

This month also has some real time observing opportunities involving all the naked-eye planets. During your morning commute you have probably already noticed Venus as a bright beacon in the eastern sky. It will be joined by much fainter Mercury as the month progresses. After sunset, Jupiter and Saturn continue the show they have been performing for the past several months, drawing closer and closer low in the southwest as the days progress. Mars is also visible in the evening, though much fainter, high in the south near the Great Square of Pegasus.

I strongly encourage readers to take a look at Jupiter and Saturn at every opportunity this month and next, because in December the two will appear closer to each other than they have since 1623. Like me, you probably missed that one so you won’t want to miss this one, easily visible next month helping you enjoy what’s up in the sky.

This month in history:

Nov 6: Tycho Brahe records bright new star (supernova) in Cassiopeia – 1572
Nov 9: Carl Sagan born. – 1934
Nov 12: Great Leonid Meteor Shower – 1833
Nov 16: Interstellar message broadcast from Arecibo radio telescope – 1974
Nov 19: Second lunar landing made by Apollo 12 – 1969
Nov 20: Edwin Hubble born – 1889
Nov 27: First photograph of a meteor shower – 1885

Sep 10

What’s Up in the Sky

What’s Up in the Sky – September, 2020

Astronomy as an Art Form

There’s way more to astronomy than just “what’s up in the sky”. Sometimes the intersection of several branches of science or the combination of science and art can lead to some fascinating discoveries or the confirmation of existing theories.

Such is the case with the Dutch artist Johannes Vermeer’s 1696 masterpiece, View of Delft, the painting that has been hailed as Vermeer’s greatest work. Vincent van Gogh described it as “incredible”. French writer Marcel Proust thought it was “the most beautiful painting in the world”.

However, there has never been total agreement about the actual date the work was created. The appearance of the trees and boats and the various lighting effects created on the canvas led to all sorts of conclusions regarding the date and time of day depicted.

A recent article by Donald W. Olson and others in the September issue of Sky and Telescope magazine describes how astronomers answered the question of when the piece was actually painted. According to the authors, “The dark town wall and entrance gates make a dramatic contrast with brilliant sunlight that illuminates Delft’s tiled roofs and the tower of the Nieuwe Kerk (New Church).” This octagonal tower was crucial in determining the time of the painting.

First, the exact direction of the main face of the tower (which is still standing) was determined using Google Earth. Simple geometry then determines the orientation of all eight faces of the octagonal tower. The apparent size of the tower in the painting is another critical factor so the authors actually travelled to Delft and used their tape measures to find out for themselves.

Knowing the exact orientation and dimensions of the tower, the team was able to narrow down the date of the painting to two possibilities, one in April and one in September. The dates were based on the pattern of sunlight on the many facets and architectural features of the tower. Knowing the dimension and orientation of each detail, they were able to determine the exact location of the Sun in the sky. Factoring in the time of day from the image of a clock face in the painting enabled them to determine the two possible dates. Because the painting depicts trees in full foliage, the April date was rejected and it was determined that the piece was done at 8 a.m. on a date near September 3.

The exact year took a little more detective work. In 1660, a clock and bells were installed in the octagonal tower, but these are not shown in Vermeer’s painting. Therefore, the date of the work is thought to be September 3, 1659.

I found this to be a fascinating example of how our endeavors here on Earth are intrinsically linked to what’s up in the sky.

This month in history:
Sept 1 Pioneer 11 is first spacecraft to fly past Saturn – 1979
Sept 3 Last two Apollo Moon landings canceled by NASA – 1970
Sept 8 Voyager 1 launched – 1977
Sept 10 Surveyor 5 lands on Moon – 1967
Sept 23 Premier of “The Jetsons” – 1962
Sept 25 59 – day Skylab 3 mission ends – 1973

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