Archive for January, 2017

The Sky This Week, January 24 – 31, 2017 !

The Sky This Week, 2017 January 24 – 31

Other winter wonders.
Messier 38 and NGC 1907, star clusters in Auriga, imaged 2016 December 31
with a 102mm f/6.6 Explore Scientific AR-102 refractor
and a Canon EOS Rebel T2i DSLR from Mollusk, Virginia

The Moon starts the week as a waning crescent in the pre-dawn sky and ends the week as a waxing crescent in the evening sky. In between we’ll have New Moon, which occurs on the 27th at 7:07 pm Eastern Standard Time. You’ll have a great photo opportunity to catch the Moon, Venus, and Mars together in the early evening sky on the 31st, forming a nice grouping spanning about five degrees of the sky.

You can continue contributing your observations to the Globe at Night program through the evening of the 28th. As we mentioned last week, this is a citizen-science program designed to map the distribution of artificial light in our night sky. The focus for this month is the constellation of Orion, the Hunter, one of the most recognized star patterns in the entire sky.

The winter sky offers other bright constellations in addition to Orion, and there are plenty of interesting things to see in these other star patterns. One of the most prominent is Auriga, the Charioteer, which lies directly overhead in temperate northern latitudes at around 9:30 pm local time. Auriga is led by a beautiful yellow-tinted star, Capella, which is the sixth-brightest star in the sky. Capella is a very close double-binary star system consisting of two bright yellow giant stars and two very faint red dwarf companions. Close by Capella you’ll find a small triangle of stars known as “The Kids”. In mythology they were associated with Capella, which represented the she-goat that suckled the infant Zeus. The rest of the constellation resembles a pentagon in shape, and its second-brightest star El Nath also marks the tip of the northern “horn” of Taurus, the Bull. From a dark location you’ll see the faint glow of the winter Milky Way coursing through the middle of Auriga, and you can spend quite a bit of time sweeping the constellation with binoculars or a low-power telescope. Charles Messier identified three bright star clusters in Auriga in the 18th Century from his rooftop observatory in Paris, and these are some of the finest examples of their kind in the entire sky. My favorite views of them are through my 4-inch wide-field refractor telescope, which also reveals many other luminous clumps of unresolved clusters among the Milky Way star clouds.

The early evening sky finds Venus and Mars high in the southwest as evening twilight fades to darkness. Venus has been pursuing the red planet for several weeks, and this week she gets about as close to Mars as she’s going to get. They are separated by just over five degrees for the duration of the week, and they will remain close to each other for the next two weeks. During the second half of February they will begin to separate as mars slogs eastward along the ecliptic and Venus begins her precipitous drop toward the Sun. The two planets will get a close visit from the Moon on the evening of the 31st.

Jupiter is still best seen in the pre-dawn sky, but the giant planet is making inroads into the evening sky. He begins to rise just before midnight after the 19th. You’ll find him just over three degrees north of the bright star Spica as morning twilight begins to brighten the horizon.

Saturn can be found low in the southeast as morning twilight gathers. He is now slowly drifting eastward through the starfields of the summer Milky Way just east of the constellation Sagittarius.

Take a few minutes this week to remember some pioneers in the America space program. Fifty years ago on the 27th Virgil “Gus” Grissom, Edward White, and Roger Chaffee perished in a ground test of the first crewed Apollo mission, and 31 years ago on the 28th the Space Shuttle Challenger exploded 72 seconds after launch with its crew of seven astronauts.


The Sky This Week, January 17 – 24, 2017 !

The Sky This Week, 2017 January 17 – 24

Count stars in Orion for science!
Messier 42, the Great Orion Nebula, imaged 2016 December 31
with a 102mm f/6.6 Explore Scientific AR-102 refractor
and a Canon EOS Rebel T2i DSLR from Mollusk, Virginia

The Moon wanes in the morning sky this week, starting the week among the springtime constellations, then moving into the first rising stars of the summer sky. Last Quarter occurs on the 19th at 5:13 pm Eastern Standard Time. Early risers have a couple of good photo opportunities in the pre-dawn hours as Luna passes just north of the planet Jupiter and the bright star Spica on the morning of the 19th. She stands close to Saturn in the southeastern sky as twilight gathers on the morning of the 24th.

The first citizen-science observing campaign for 2017’s Globe at Night program gets underway on the evening of the 19th and runs through the 28th. The goal of the program is to monitor the brightness of the night sky on a global scale to map out areas that can be considered “dark sky friendly” to amateur and professional astronomers alike. The web-based program invites anyone with an interest in the night sky to submit their observations of key constellations throughout the year. In 2016 over 14,000 people contributed observations, and this year they hope to surpass that number. This is a perfect time to get started, since the constellation that is the center of attention is Orion, perhaps the brightest and most recognized star pattern in the heavens. Located along the celestial equator, Orion is visible from every inhabited place on the planet and sports a variety of stars over a wide range of visible magnitudes. To participate in the program visit the Globe at Night website. There you’ll receive instructions and can view star maps with different magnitude cutoffs. If you have a smart phone you can download apps that will guide you through the process. You may submit as many observations as you wish, and I encourage everyone to do so, especially when vacationing away from city lights. Why should we do this? Dark skies are becoming harder to find; it is estimated that some 80% of the U.S. population has never seen the Milky Way! Artificial lighting not only robs us of a clear view of the sky, it also upsets biological cycles in many of the planet’s species, including humans. Fortunately controlling “light pollution” is easily done with today’s lighting technology, and it saves energy resources that can be applied to another purpose. Your participation is the key.

After you’ve counted stars in Orion, take a few minutes to sweep over the constellation with binoculars. This simple optical aid really enhances the colors of the Hunter’s stars and brings a host of fainter ones into view. One of my favorite areas to look at is the Hunter’s “Sword”, which dangles just below the left side of the famous “Belt” stars. With the naked eye you can see three faint clumps of stars, but the binoculars reveal much more. The top and bottom “stars” turn out to be clusters of blue luminaries, while the middle member shows stars embedded in a glowing mass of light. This is the famous Great Nebula, Messier 42, the site where most of the stars in the constellation formed. Often regarded as one of the telescopic showpieces of the sky, it is one of the largest stellar nurseries in the Galaxy.

Venus dominates the western sky in the early evening. There is no mistaking the dazzling planet; under a dark sky she is bright enough to cast shadows. She is now at her best placement in the evening sky and will remain a fixture until March, when she will undergo a precipitous drop toward the Sun.

Mars remains a few steps ahead of Venus as the two planets move into the dim constellation of Pisces. The two objects are just over six degrees apart by the week’s end. For the next few weeks they will stay in his configuration before Venus falls away from the red planet.

Jupiter crosses the meridian at around 6:00 am EST, placing him in an ideal spot for a telescopic view before starting your day. Old Jove is now just over three degrees from the bright star Spica, and he’ll spend the next few weeks near the star. The Moon pays a visit on the morning of the 19th.

You’ll find Saturn low on the southeast about 45 minutes before sunrise in the gathering morning twilight. The Moon is close to the ringed planet on the morning of the 24th.

The Sky This Week, January 10 – 17, 2017 !

The Sky This Week, 2017 January 10 – 17

Colors in the starry sky.
Orion over Paris, Virginia, 2014 March 27
imaged with a Canon EOS Rebel T2i DSLR

The Moon dominates the overnight hours this week, beaming brightly down from nearly overhead as she passes through the Full Moon phase on the 12th at 6:34 am Eastern Standard Time. January’s Full Moon is popularly known as the Wolf Moon, a name derived from Native American lore, or the Moon After Yule. Look for the waning gibbous Moon rising within a degree of the bright star Regulus late on the evening of the 14th. Shortly after midnight on the 17th the Moon will occult the second-magnitude star Porrima at 12:08 am EST.

Despite the best efforts of the Moon to wash out the winter sky, our evening hours now play host to the year’s best collection of bright stars. Nine of the 25 brightest stars in the sky can be found within the confines of Orion and the surrounding constellations. These stars also offer some of the most noticeable color variations that you can see with the unaided eye. One of the most striking examples of brightness and color can be found in the first-magnitude star Betelgeuse, which marks one of the “shoulders” of the familiar constellation of Orion, the Hunter. The ruddy tint of Betelgeuse stands in stark contrast to the blue-white colors of Orion’s other bright luminary, Rigel, and the distinctive stars of the Hunter’s Belt. Betelgeuse is classified as a red supergiant star that is in the later stages of its evolution. It has exhausted the hydrogen in its core and is now fusing hydrogen into helium in an ever-expanding shell surrounding the core. This has caused the star’s outer layers to swell to vast proportions; its radius is over 800 times that of the Sun. Its girth is so vast that if it occupied the Sun’s place in our solar system the Earth would be inside its outer layers! The mass of Betelgeuse is over 10 times that of Old Sol, and this large mass means that the star is now at a very unstable phase of its evolution. Of all the bright stars in the sky Betelgeuse is the most likely candidate to explode in a supernova, but we have no way of predicting when this might occur. It is well over 600 light-years away, so it could have blown up 300 years ago and we’ll still have to wait another 300 years to find out! In classical mythology Orion was killed by the sting of a lowly scorpion, and we still see this in the constellations today. The brightest star in Scorpius, Antares, is a very similar star to Betelgeuse, but you’ll never see them in the sky together. Throughout the ages Betelgeuse has set when Antares rises as the Hunter and the Scorpion perpetually chase each other across the heavens.

Venus reaches her greatest elongation east of the Sun on the morning of the 12th. You should have no trouble finding Venus in the early evening sky as she moves eastward through the dim stars of Aquarius. For the next few weeks Venus will climb northward along the ecliptic before she begins her fall back toward the Sun in late February. Through the telescope she resembles the first quarter Moon, and over the next few weeks her phase will become more crescent-shaped as her apparent diameter grows ever larger.

Mars may also be found in Aquarius just to the northeast of Venus. Venus continues to close the gap with Mars, but the dazzling planet won’t be able to catch him before she starts her fall toward the horizon. Mars will continue his eastward slog and will remain visible in the evening sky until the late spring.

Jupiter now rises about half an hour after local midnight, which means that he now crosses the meridian at around 6:00 am EST. With sunrise still taking place at around 7:25 am this is a great opportunity to spend a little time looking at the giant planet before you start your days’ activities. Jupiter’s four large moons were first observed by the astronomer Galileo Galilei 407 years ago this week.

Saturn and Mercury can be spotted low in the southeast about half an hour before sunrise. Both planets are around zero magnitude and are located about 10 degrees above the horizon, separated by about six degrees as the week opens. By the week’s end the gap between them grows as Mercury moves east of Saturn and gradually brightens.

The Sky This Week, January 3 – 10, 2017 !

The Sky This Week, 2017 January 3 – 10

A great week to try out that new telescope.
Last Moon of the year, 2016 December 30
imaged from Mollusk, Virginia with a Canon EOS Rebel T2i DSLR

The Moon waxes in the evening sky this week, passing the First Quarter phase on the 5th at 2:47 pm Eastern Standard Time. Luna begins the week to the northeast of ruddy Mars, then embarks on a trek through the dim autumnal constellations. By the end of the week she passes the bright star Aldebaran.

The Earth reaches perihelion, its closest point to the Sun, on the 4th at 9:18 am EST. At this time the distance between the center of our planet and that of the Sun will be just over 147 million kilometers (91,404,000 miles). We’ll reach our most distant point from Old Sol on July 3rd.

The first lunation of the year provides an excellent target for those of you who may have received a telescope as a holiday gift. The Moon is the easiest object in the sky to observe, and it is also probably the most rewarding. Suddenly that object that you’ve grown accustomed to as a thing in the sky becomes an actual place, a world of countless topographic forms that present a different view on each successive night. This is a great time to get to know your telescope and its accessories. The Moon makes it easy to align the finder scope, and you can explore the different magnifying powers of the telescope’s different eyepieces. Start your lunar tour with the lowest power eyepiece, which will have the largest focal length (i.e. 25 mm) etched on its collar. Once you’ve become familiar with the general view and the tracking ability of your instrument, use shorter focal length eyepieces to increase the magnification. The amount of detail that you see will be dependent on your telescope’s aperture, but even small aperture telescopes will do quite well with Luna as a target. Once you are familiar with the Moon’s general appearance, download a lunar map or a lunar atlas app and get to know the more prominent features. With a little patience you’ll learn to find your way around our only natural satellite, and you’ll be able to spend many hours over the future years continually finding new features to explore. We often say that the Moon is “looked over, then overlooked” by amateur astronomers, but even after 50 years of viewing I have yet to grow tired of peering at Luna’s stark and beautiful landscapes.

Venus will probably be your next target. She is impossible to miss in the early evening sky, blazing away in the southwest in the deepening evening twilight. Through the telescope she presents a dazzling white disc that currently resembles a slightly gibbous Moon. Over the course of the next two months her apparent size will grow as her phase becomes more of a crescent shape.

Mars may be found a bit higher in the sky northeast of Venus and will be the brightest object in the southwest after the dazzling planet. The red planet is now moving through the dim constellation of Aquarius and can be easily identified by his colorful tint. Through the telescope Mars is a tiny pink-orange dot; don’t expect to see much detail, even in a large-aperture telescope.

Most of the planetary action takes place in the morning sky this week. Giant Jupiter rises at around 1:00 am EST, but he’s best placed for a telescopic view in the hours before sunrise. Jupiter and the four moons first recorded by Galileo are visible in any decent telescope, and the moons’ positions will change from night to night. Telescopes of four inches or more aperture will begin to reveal details on the planet itself.

You’ll find Saturn lurking about 10 degrees above the southeast horizon in the gathering morning twilight about 45 minutes before sunrise. You might catch a quick glimpse of him before the sky becomes too bright, but he’ll provide much more rewarding views during the summer months.