Monthly Night Sky Report: December 2023

          Introduction

    The second half of November brought more cloudy skies and snow to Utah. The temperatures also declined slightly, making stargazing a little more unpleasant. Even under these conditions, I could see Jupiter and Saturn in the evening sky, with an 80% lit Moon between the pair on the 22nd. Venus and Orion were easily visible in the early morning sky before sunrise.   

       Aside from colder weather and more snow, December also brings the return of two meteor showers, the Geminids and the Ursids. No planets will reach opposition this month, but three asteroids will. However, a telescope and a star chart is recommended to see them. The winter solstice will also occur this month, marking the time when the daylight hours begin to lengthen and the hours of darkness grow shorter.

             

Mercury

    Mercury should be observed in early December. This tiny planet will reach its greatest eastern elongation on the 4th, giving an observer an extra few minutes to view. A thin crescent Moon will join Mercury in the sky on the 14th. Just over a week later, on the 22nd, Mercury will reach inferior conjunction with the Sun, becoming lost from view.    

  

Venus

    Venus can be found shining brightly above the eastern horizon before sunrise. The bright star, Spica, in Virgo, can be found less than 5° away at the beginning of the month. Venus will pass through Virgo by mid-month and spend the remainder of December in Libra. On the 9th, a thin crescent Moon will join Venus in the morning sky. 

    

Mars

    Mars will remain too close to the Sun to be safely viewed during December. 

Jupiter

Saturn

     

    The gas giants will remain great targets for binoculars and telescopes. Having recently reached opposition, Jupiter will be visible during most of the night throughout December. A pair of binoculars will easily reveal the four Galilean Moons, while a telescope can show observers the Great Red Spot, cloud bands, and transits of the Galilean Moons. On the 22nd, the Earth's own Moon can be found just 5° from Jupiter. A short distance away, the Pleiades can also be found.  

    Saturn can be found in Aquarius, high in the southwest sky, after sunset during December. Even in cold temperatures, the ringed planet is still worth a look. The Moon will pass just 2° from Saturn on the 17th.     

   

       

Neptune

Uranus

    

    The two ice giants can be viewed through binoculars but will look their best through a telescope. Uranus reached opposition during November, making this planet visible nearly all night throughout December. This ice giant can be found about halfway between Jupiter and the Pleiades. A nearly Full Moon will join this planet in the sky on the 23rd when the pair will be just 3° apart.

    Neptune can be found trailing Saturn in the planet trail. The most distant planet will be visible most of the night during December, but interested observers should view its blue disk before midnight to get the best views. The Moon joins Neptune in the sky on the 19th.

Meteor Showers and Asteroids

     December will offer plenty for interested observers to view. Unfortunately, most of these events occur later in the month when most individuals are busy with holiday plans. Nevertheless, the Geminid Meteor Shower will peak on the 14th under a Moon-free sky. Observers can expect approximately 150 meteors per hour radiating from the constellation Gemini. 

    The second meteor shower will peak on the 22nd but may be subpar due to a 74% lit Moon in the sky. The Ursids can produce up to 10 meteors per hour, but outbursts have occurred with rates of up to 25 meteors per hour. Look towards Ursa Major to view these meteors.

    Three main belt asteroids will reach opposition this month, beginning with Vesta. Each asteroid will require a pair of binoculars to view, but I highly recommend a telescope and a star chart (or phone app). Vesta can be found on the border of Orion and Gemini on the 21st, its date of opposition. Use Betelgeuse and Saiph (the star that represents the knee of Orion) to form a line towards Vesta. A star chart is helpful so that it can be compared to the field of view, so the observer knows which point of light is the asteroid.

    The next asteroid to reach opposition is Metis. This occurs on the 22nd. Follow the line formed with Saiph and Betelgeuse and continue through Vesta to reach Metis. Again, a star chart will be helpful to compare this region of the sky with the field of view through a telescope. The "extra" point of light will be Metis.  

    The final asteroid to reach opposition this month is Astraea. This opposition will occur on the 27th. On this date, an observer can form a line through Rigel and Betelgeuse and continue towards Gemini. On the border of these two constellations, the observer will notice a point of light that does not appear on star charts. This is the asteroid Astraea. An observer can also view the region of the sky where these asteroids are located and notice them move over different nights.          

 

Monthly Breakdown

December 04: Mercury reaches greatest eastern elongation
December 05: Last Quarter Moon🌗
December 09: Moon passes within 4° of Venus
December 12: New Moon 🌑
December 13: Moon passes within 4° of Mercury
December 13/14: Geminid Meteor Shower peaks 🌠
December 17: Moon passes within 2° of Saturn
December 19: Moon passes within 2° of Neptune
December 19: First Quarter Moon 🌓
December 21: Asteroid Vesta reaches opposition
December 21: Winter Solstice
December 21/22: Ursid Meteor Shower peaks 🌠
December 22: Asteroid Metis reaches opposition 
December 22: Moon passes within 3° of Jupiter
December 23: Moon passes within 3° of Uranus  
December 26: Full Moon 🌕
December 27: Asteroid Astraea reaches opposition

         

Now get outside and look up!

Planet images were taken by NASA.

Andrew vs. the Cosmos image was taken by Jeff Greenland.

The Milky Way and Trees image was taken by Andrew Greenland.

Orion, Taurus, and Pleiades image was taken by Andrew Greenland.

    

Midmonth Check-In: November 2023 and Venus

     

Introduction and Monthly Reminders   

    The cooler temperatures are definitely settling in over Utah. We experienced a couple of stormy days with the mountains receiving snow. Even with the cooler weather and stormy days, I could view Jupiter as it reached opposition on the 3rd. I could also view Venus and Jupiter in the early morning sky and Orion the Hunter with his two hunting dogs, Canis Major and Canis Minor. Uranus also reached opposition during the first half of the month and a close encounter between the Moon and Antares on the 14th. I wanted to travel down to Richfield, Utah, again during the first half of November to attempt an astrophotography timelapse, but unfortunately, the weather intervened. 

    Observers can still view the Leonid Meteor Shower on the evening of the 17th and early morning hours of the 18th. There will also be many close approaches between the Moon and the outer planets of the solar system. Mercury will pass close to Antares on the 16th, while Venus will pass close to Spica on the 28th.    

    

Venus

     Last month, I discussed Mercury's formation, traits, and missions. This month, the solar system tour will continue with the second closest planet to the Sun, Venus. The second planet out from the Sun formed at the same time as the rest of the solar system, approximately 4.6 billion years ago. It can be found about 0.72 AU (67 million miles), on average, from the Sun, where the Earth is 1 AU (93 million miles). Venus is the third brightest object in the sky, trailing only behind the Sun and the Moon. Venus is so bright that it can even be seen during the day if the air is free of pollution. Venus is named after the Roman goddess of love and beauty and is the only planet named after a female god. 

     The interior of Venus closely resembles that of the Earth. It is theorized that if the Earth and Venus were cut in half and placed next to each other, an observer could not tell the two apart. Venus is also similar in size to Earth, being only 405 miles smaller across than the Earth. These similarities have earned Venus the nickname "Sister Planet" to the Earth. Unfortunately, this is where the similarities end. 

     Venus is a planet of extremes. If Earth and Venus were twins, the Earth would be the even-tempered twin while Venus would be the extraordinarily aggressive and hot-tempered sibling. The surface of Venus is estimated to have over 1600 major volcanoes and thousands more smaller ones, a majority of which are active. These active volcanoes aid in constantly resurfacing the planet, allowing very few impact craters to be seen, similar to Earth. The surface of Venus can reach lead-melting temperatures of 870° Fahrenheit, the hottest surface temperature of any other planet in the solar system. These extreme temperatures are caused by Venus' closeness to the Sun and its thick carbon dioxide atmosphere that traps heat. Venus also has mountains and valleys like the Earth, but of course, it does not have any liquid water since water turns to steam at temperatures above 212 degrees Fahrenheit.    

    While the Earth and Venus both have an iron core encased by a mantle and a thin rocky exterior, our Sister Planet does not have a magnetosphere of its own. Venus instead gets its weak magnetic field from the Sun's magnetic field interacting with the planet's atmosphere. As mentioned, the atmosphere of Venus is mostly made up of carbon dioxide, the same gas that is behind the greenhouse effect on Earth. Instead of having clouds made up of water vapor like the Earth, Venus has clouds composed of sulfuric acid. Higher in the planet's atmosphere, the temperatures ease a bit with a range of 86 degrees to 158 degrees Fahrenheit. In this region of the atmosphere, Venus experiences wind speeds up to 224 miles per hour, about the same speed as hurricane-force winds on Earth. The thick atmosphere of Venus also contributes to its high albedo, or reflective properties, causing the planet to appear bright in our sky. Venus has an albedo of approximately 0.7 which means nearly 70% of the Sun's light is reflected. Recall that the albedo of Mercury was only 0.14, and the Moon has an albedo of 0.1.  

    Since Venus is on the inside track around the Sun, compared to the Earth, observers can view the planet go through phases, like the Moon. A pair of binoculars can reveal these phases, although personally, I have had better luck with a telescope. Unlike the Moon and other planets in the solar system, Venus (and Mercury) can never have a "full" phase since when they are opposite of the Sun from our Earthly perspective, they will be behind our star. However, the inner planets can pass between the Sun and the Earth, creating a planetary transit. The last transit of Venus occurred in 2012 and won't happen again until 2117. I was able to capture a few blurry images during the 2012 transit. The best of which is included below.

Transit of Venus in 2012. Some sunspots were also visible. 

     The Earth's evil sister planet also has a much different spin than what humans are used to. Venus rotates about its axis in the opposite direction as the Earth, meaning the Sun rises in the west and sets in the east. Venus also spins extremely slow, with a day on the planet being longer than a year. Venus does not experience seasons like the Earth either, due to it only having a 3 degree tilt while our planet has about a 23 degree tilt. 

    There have been many missions to Venus, most of which have been Russian missions. There are currently three known missions in the works to return to Venus.`         

   

Spin

Day vs year length

missions

 

    

Now get outside and look up!