Stargazing in the January Sky

by Cam Wipper, CFHT remote observer

What You Need: Just your eyes! Everything in this guide can be seen with nothing more than your very own eyes. No special equipment required.

Where To Go: We here on the Big Island are blessed with some of the greatest night skies on Earth. You can find many of the targets listed here from your own backyard. Of course, if you live in Waimea, Hilo or Kailua, the lights of your town can make fainter objects more difficult to see. The best locations are those far from light sources. Some of my favourite locations are Pu’u Huluhulu off of Saddle Road (across from the Maunakea Access Road), along Chain of Craters Road in Hawai’i Volcanoes National Park (remember: there is no entrance fee after 8pm— perfect for stargazers) and along Mana Road on the slopes of Maunakea.

Surprisingly, the summit of Maunakea, though unbeatable for telescopes, is not the best site for human observers. Due to the thinness of the air, and resultant dearth of oxygen, at the altitude of the summit, human night vision becomes far less efficient than at altitudes closer to sea level. For this reason, it is best to stargaze no higher than 10,000 feet (3000 m). The Maunakea Visitor Information Station is an example of a site located near this elevation.

What To Look For: The new year starts off with a bang as, in the first week, we have the Quadrantids Meteor Shower. Also at their best this month are the planets of Venus and Mercury along with our staggering winter sky.

Sunrise and sunset times for Waimea
Sunrise and sunset times for Waimea

Barely after the fireworks marking the arrival of 2017 begin to fade, we’ll find the celestial type starting up. The Quadrantids Meteor Shower runs from January 1st to 5th, with the peak on the night of January 3rd/4th. On this night the hourly rate of meteors will top out around 40 per hour. With moonset around midnight, the best time to watch for these meteors will be between midnight and sunrise.  While the peak of the shower has passed, some stray meteorites may be visible into early next week.

Interestingly, this shower is one of the few prominent showers not named for a modern constellation. Rather, it is named for the now-obsolete constellation Quadrans Muralis, which was eliminated from the sky in 1922 when the International Astronomical Union divided the sky into the 88 modern constellations we know today. Most of Quadrans Muralis is now part of Boötes, the Herdsman, and as such, the Quadrantids Meteor Shower is described as emanating from the constellation Boötes.

As mentioned at the top of the article, we also have great views of Mercury and Venus this month. We’ll start with the easiest of the two to find: Venus. It’s likely that you’ve been admiring Venus for weeks now as it can be found high in the western sky after sunset. As the third brightest object in the sky—after the Sun and Moon, respectively—it is always the very first object to appear after sunset. On January 12th, it will reach a position known as Greatest Eastern Elongation. This is, in terms of angular distance, Venus’s greatest separation from the Sun. On this evening Venus will be 47.1° away the Sun and at its highest point above the horizon at sunset.

About a week after Venus, we can then look for Mercury. Mercury will be at its Greatest Western Elongation, which as you might have guessed is the opposite of Venus’s Greatest Eastern Elongation. As a result, Mercury will not be visible in the evening, but in the morning. On the morning on January 19th, Mercury will be 24.1° from the Sun. Look for it low in the eastern sky just before

Mercury and Saturn in the sky just before dawn from Maunakea
Mercury and Saturn in the sky just before dawn from Maunakea

sunrise.

Venus and Mercury are not our only planets visible this month. Located above Venus in the Red Planet, Mars. With each passing day, Earth’s two next door neighbors are growing closer and closer together. Look for them both in the evening sky all month.  If you’re up early looking for Mercury—the smallest planet in the Solar System—you can also find the largest: Jupiter. Jupiter appears around 02:00am early in the month, before rising as early as midnight at the end. As the second brightest planet after Venus, it will be easy to spot in the morning sky.

Lastly, joining Mercury in the early morning sky is our ringed planet Saturn. Both are fairly faint—Mercury due to it’s size and Saturn due to it’s distance—and appear shortly before sunset. Saturn rises around 05:00am and Mercury at 05:30am on January 19th, on the morning of Mercury’s Greatest Western Elongation. Additionally, on the morning of January 24th, Saturn is joined by the waning crescent Moon for a beautiful pairing in the approaching twilight.

Moving on the stars: Winter continues on Earth and we continue to be treated to our winter sky in the early evening.

Moon phases for Waimea
Moon phases for Waimea

We’ll start in the north with the Little Dipper. Visible all night, the Little Dipper, or Ursa Minor—the Little Bear—is rather dim. Far less obvious than it’s larger brother, the Big Dipper, the Little Dipper is nevertheless very important: it contains the star Polaris. Also known as the North Star, Polaris is the star at the very end of the Little Dipper’s handle. As this star is located just about at the Earth’s axis of rotation, Polaris never appears to move. The Little Dipper, and indeed the entire sky, simply spins around it. Polaris is also very important for navigation. Because of it’s location, one can use it to locate the direction North. Additionally, the latitude of one’s location on Earth can be determined by the North Star. This can be done by approximating the elevation of the North Star above the northern horizon. This elevation (in degrees) is the same as the latitude of your location! For example in Hawaii, the North Star is about 20 degrees above the horizon. Our islands are between 18 and 22 degrees North in latitude.

Staring in the east we have Taurus, the Bull, and it’s bright red star, Aldebaran, often called the “Eye of the Bull”.

Below Taurus, we have one of the most famous constellations in the sky: Orion. The famous Belt of Orion is one of the easiest night sky features to find. Look for a vertical row of three bright stars almost due east. To the north of them you will find Betelgeuse, a huge red supergiant star nearing the end of it’s life. To the south, you will see Rigel, a blue-white supergiant, estimated to be around 200,000 times more luminous than the Sun. These two stars are the ninth- and seventh-brightest stars in the night sky respectively.

Although, nearby in the sky, Taurus and Orion are not friends. Greek mythology describes Taurus and Orion as fighting in the sky, with Taurus defending the Seven Sisters from Orion’s rather lustful advances.

These sisters, in reality a stunning group of stars known as an Open Cluster, can be found as well. They are more commonly known as the Pleiades, and are positioned just above Taurus. A quick way to find them is to locate Betelgeuse. Then trace a line in the sky to connect Betelgeuse with Aldebaran. Finally continue that line past Aldebaran, and you will come to the Pleiades.

The Pleiades are well known across the Northern Hemisphere for their beauty and cultures around the world have their names for the group. In Hawaii, they are known as Makali’i, and they are mentioned several times in the Kumulipo, the Hawaiian Creation Chant, including on the fifth line of very first verse.
In Japan they are known as Subaru, a name which graces not only a successful automobile manufacturer (now you know my their logo are stars!), but also a telescope on Mauna Kea, which as you may guess, is owned by Japan.

Finally, in west we have the great legend of Perseus and Andromeda, playing out in the skies above our heads. The characters of this legend, the hero Perseus, the princess Andromeda, the king Cepheus, the queen Cassiopeia, the winged-horse Pegasus and the great monster Cetus can all be found in the sky tonight. The easiest of these characters to find are Pegasus and Cassiopeia. Pegasus most recognizable feature is the ‘Great Square’, as asterism of four stars which can be found in the east in the early evening, rising as the night goes on. Just to the north, we can see the characteristic ‘W’ shape of Cassiopeia.

Andromeda Galaxy and it's satellite M32 imaged by Megacam at CFHT  (note, it won't look like this with your eyes)
Andromeda Galaxy and it’s satellite M32 imaged by Megacam at CFHT
(note, it won’t look like this with your eyes)

Andromeda is a special constellation as it contains the most distant object visible to the human eye: the Andromeda Galaxy. This galaxy, likely at least twice the size of the Milky Way, is our galactic neighbor. It is so far away that the light reaching your eye from the stars in Andromeda has been traveling across space—at the speed of light—since before the human race even existed on the surface of the Earth.

Finally, we have our first glimpse of the famous Southern Cross. With Hawaii being the only state in the USA to have a view of this iconic southern constellation, it’s appearance is a real treat for visitors and kama’aina alike. Look for it in the early morning sky before sunrise low in the, you guessed, southern sky.

With that, I wish you clear skies and happy stargazing!
If you have any questions, comments or are new to stargazing and would like some tips on getting started, email me at wipper@cfht.hawaii.edu. Aloha!

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