In July we talked about using the Summer Triangle asterism to locate Messier 57, the Ring Nebula.  If you were able to make it to our August Star Party at Pronghorn Park in Prescott Valley, you most likely were able to view it and the planets Saturn and Jupiter shining bright at opposition.  M57 however is just one of the heavenly surprises hiding within the Summer Triangle.

One of the three points of the Summer Triangle is Deneb, the brightest star in the constellation Cygnus, the Swan.  The main stars of the Swan make up the Northern Cross, making it easily identifiable to the naked eye just after sunset.  Move down from Deneb to about midway between Vega and Altair, and the main body of the Northern Cross is formed with Deneb at the top and Albireo at the bottom.  Inversely, the Swan is viewed as diving down, with Deneb at the Tail and Albireo as the head.  Albireo appears as one bright star until a look through your binoculars or telescope reveal it to be a fun double star, with Albireo A being the brighter yellow star and Albireo B a smaller blue star.  It is believed that these two stars are not actually a binary system and orbiting each other, as Albireo B is most likely 300 light years further past Albireo B, and just appears to be a neighbor as viewed from Earth.

Another fun object to view in the Summer Triangle is M27 – The Dumbbell Nebula.  The first planetary nebula to be discovered during Messier’s charting of non-comets, The Dumbbell nebula is much larger and closer than the Ring Nebula and has a higher reflectivity.  This makes it much easier to find with binoculars, and higher magnification with a telescope reveals a beautiful shape and some color.

The “Dog Days of Summer” is an expression often used to define a seasonal period of stagnation or inactivity, usually brought on by long days and extreme heat.  In the Arizona Central Highlands – similar to that experienced by our ancient predecessors in Greece and Rome – this time correlates with the beginning of the monsoon season, connected with heat and drought, but also sudden thunderstorms.  While we may feel like spending this time laying in a backyard kiddie pool with our dog, the term has absolutely nothing to do with terrestrial canines, and everything to do with astronomy.

The three stars of Orion’s belt point almost directly to the bright star Sirius which, in ancient times, returned to view in the Northern hemisphere at the hottest phase of summer, and just prior to the annual flooding of the Nile River valley.  Being not only the brightest star in the sky but also in its constellation Canis Major “The Greater Dog”, it was often referred to as the “Dog Star”.  It is from this reference that we still call this time of year the “Dog Days of Summer”.

This year, we can experience the opposition of both Saturn and Jupiter during this time, as we reach closest approach to these gas giants on August 2^nd and 19^th, respectively.  Just a few days on either side of the August 8^th New Moon, this is the best opportunity of the year to view details of these planets and their natural satellites.  With the Sun giving us the brightest illumination on these evenings, even small to medium sized telescopes can pick out the weather bands of Jupiter, ring divisions around Saturn, and a handful of moons around each.  Specifically with Jupiter, watch over consecutive nights and sketch the locations of the four Galilean moons you see, documenting how they change position during their orbits from evening to evening.

Join us the evening of August 7^th at Pronghorn Park in Prescott Valley for the opportunity to view these and other objects in the night sky!

If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at www.prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event. 

By Adam England, The Backyard Astronomer

The beginning of Summer in the Northern Hemisphere brings warmer nights to the backyard astronomer, a stark contrast from the oft freezing viewing sessions of the Winter constellations.  July offers longer days, but also some great stargazing for the moderate sized telescope.  The constellations Aquila the Eagle, Cygnus the Swan, and Lyra the Lyre converge directly overhead at solar midnight, with their three brightest stars forming the Summer Triangle.  Easily identifiable asterisms such as the Big Dipper, the Southern Cross, and the Summer Triangle have long been a way for the layperson to identify patterns of stars.

The Big Dipper is probably the first asterism kids in North America become familiar with.  Popularized as the “Drinking Gourd” from an African American folk song in the 1920’s, the end stars of the bowl form a line to the bright star Polaris, the star closest to Earth’s Celestial Northern Pole, which helped lead escaped slaves North to freedom.

The Southern Cross is a series of 4 (sometimes 5) bright stars that is visible in the Southern Hemisphere nearly any time of year.  Used in a similar fashion to find Earth’s Southern Celestial Pole, everyone from ancient Pacific navigators to Argentine gauchos have used this grouping of stars to navigate vast tracts of land and desolate expanses of ocean.  Used in no less than 10 national, regional, or organizational flags, Crosby, Stills, Nash and Young spoke of it in their aptly named 1982 hit “Southern Cross”, positing, “When you see the Southern Cross for the first time, you understand now why you came this way.”

The Summer Triangle is formed by the three bright stars Altair, Deneb, and Vega, with Vega being the brightest of the three.  The second star (after our Sun) to be photographed and the first to have its spectrum recorded, Vega is relatively close at just 25 light years distant and is the second brightest star visible in the Northern Hemisphere.  Just below Vega, and directly on the leg of the Triangle formed with Altair, is The Ring Nebula, a small planetary nebula formed when a dying star ejects gas in all directions as it runs out of fuel required to maintain nuclear fusion.  Becoming visible with 3–4-inch telescopes, you can begin to resolve the rings of gas and eventually the central remaining white dwarf star with 8-inch scopes and higher magnification.

The scientific community has been intently focused on Mars for the past couple months.  Every 26 months, our planets align in a way that shortens the time from Earth to Mars down to about 9 months, and as more countries develop space programs, more robotic explorers are sent to the red planet during this window.  In 2021, the UAE orbiter Hope arrived on February 9^th, China’s Tianwen-1 entered orbit on February 10^th, and the NASA Perseverance rover touched down February 18^th.  Perseverance carried with it the Ingenuity helicopter, which has spent the last month proving the first powered flight on another world, and on May 14^th, Tianwen-1 released the Zhurong rover which became only the second country to successfully land a rover on the Martian surface.

Mars is easily identifiable with the naked eye, having a deep red hue due to high levels of oxidized iron in its crust – basically the whole planet has rusted over the last couple billion years.  The arrivals of the orbiters and landers in February signaled a (relatively) close approach of our two planets, as they have spent most of 2021 pulling further distant from one another, and lower and dimmer in our night sky.  Sinking closer to the setting sun, Mars enters the constellation Cancer on June 8^th.  As the moth wanes, you may be able to catch one last conjunction with Mars passing just 0.5 arcminutes from the Beehive Cluster M44 on June 23^rd, just minutes after sunset, low in the western sky.

The Beehive Cluster – or Messier 44 – is one of the nearest open clusters to Earth.  Ptolemy referred to it as the “nebulous mass in the breast of Cancer”, proving how easily identifiable it is with the naked eye.  Galileo resolved 40 stars within the cluster, though we now count at least 1000 stars across 39 light years, which are close enough to be gravitationally bound to each other.  At least 3 exoplanets are known to orbit stars within the Beehive Cluster.  If you are lucky enough to catch the conjunction of this open cluster and our neighboring planet, both should easily fit within the field of view of your telescope or binoculars.  With the right magnification, one can resolve some nebulosity from the Beehive Cluster and the polar ice cap of Mars.

In the early morning hours of Wednesday 26 May, the Western United States will be treated to an astronomical event not seen in nearly two and a half years – a total lunar eclipse.  The 3-hour and 40-minute event will reach totality over Central Yavapai County at 4:18 AM.  The culmination of totality is often referred to as a “Blood Moon” for the deep reddish hue often reflected off the surface of the Moon.  This is a result of the Sun’s direct rays being blocked by the Earth, with only a small amount of refracted light passing through Earth’s atmosphere, like light passing through a prism.

A lunar eclipse occurs when the Earth passes directly between the Moon and Sun, essentially forming a straight line, with the Earth’s shadow cast upon the surface of the Moon.  Since astronomers love to come up with cool names for astronomical events – usually based on ancient terms of a similar albeit generally terrestrial meaning – this type of alignment is called a syzygy, from the Ancient Greek suzugos meaning “yoked together”.  All three bodies gravitationally lined up in space, they are like three oxen abreast to pull a plough.  This alignment also means the moon is in its “Full” phase as viewed from Earth, so a lunar eclipse can only occur during a full moon.

Being the brightest full moon was the one to darken, nearly disappear, and then turn a deep red color, ancient cultures often associated the lunar eclipse event as a bad omen.  Across continents and millennia, both the Inca and Chinese would attempt to scare away this demonic or evil power by throwing rocks and spears or yelling and the ringing of bells.  The Mesopotamians believed seven demons were attacking the sky, followed by the land, and specifically the King.  Using a stand-in dressed as the king to fool the would-be usurpers, the eclipse always ended without the predicted celestial battle, and the substitute king was made to disappear – often by poisoning.  However, viewing an eclipse as a harbinger of doom is not relegated to the ancient past, as fundamentalist pastors of the last decade predicted a tetrad or set of three eclipses in 2014-15 coinciding with the celebrations of Passover and Sukkot would bring about the rapture.

The Super Blood Moon Eclipse of May 2021 begins Wednesday morning at 1:47 AM when the edge of the Earth’s shadow intercepts the visible surface of the moon, peaking at 4:18 AM, and ends at 5:27 AM.  Unlike a solar eclipse, this event lasts much longer and is completely safe to observe with the naked eye.  This will also be a “Super Moon”, which may appear larger in the sky as it will be passing through perigee – the point when it is at or near its closest to Earth.

If you normally stay up late, or get up early, or just want to set your alarm, take a few minutes to get out and look up.

The Backyard Astronomer

by Adam England

The second brightest object in the night sky (after the Moon) is the planet Venus.  Records going back at least 5,000 years show human societies acknowledging that the “morning Star” and “Evening Star” were one and the same, traveling across the horizons as it circled the Sun.  The Sumerians associated Venus with the goddess Inanna, who was unique in that she was the only deity who could traverse from the netherworld and back to the heavens.  The Mayan calendar focuses on the movements of what the considered the three most important celestial bodies- The Sun, Moon, and Venus.  Many eastern cultures refer to Venus by their respective literal translations of “Metal Star”, referencing the importance they placed on it as one of the Five elements.

With advancements in visual astronomy, we learned that Venus was a terrestrial planet, with thick cloud clover, rendering landscape observations impossible.  While the early space race saw America aim for the Moon and Mars, the Soviet Union focused on the inner solar system, successfully exploring the planet with dozens of each flybys, orbiters, landers, and even the first off-earth balloons.  All of this data, as well as continuing missions and discoveries, told us that Venus was very similar to Earth in many ways, and drastically different in others.

At about 90% the size of Earth, it is the closest in size of any planet or exo-planet we have yet discovered.  Venus orbits the sun at about ¾ the distance Earth does, but rotates very slowly, completing a revolution once every 243 days.  Due to a run-away greenhouse effect, Venus also has the densest atmosphere of the rocky planets.  The air pressure on the surface is equivalent to 92 times sea level pressure on Earth, or about the same as 3000ft underwater.  Clouds of sulfuric-acid hold in the Sun’s heat, with average temperatures above 867 °F.  By all considerations, Venus is desolate, inhospitable landscape of volcanic activity, an example of what Earth could be like in a few million or billion years.

Recently, scientist used extremely powerful telescopes on Earth to analyze the Venusian atmosphere, detecting the chemical phosphine at 20 parts per billion.  While phosphine can occur naturally in nature, it is only known to be produced in such quantities by organic processes.  Without diving into a deep chemistry lesson, it suffices to say that we have no explanation as to how the phosphine would be there, except as having been produced by active anaerobic ecosystems, such as is the case with fermentation and deep sea organisms on Earth.

To catch a glimpse of our cosmic neighbor/twin during the month of October, look to the east in the hours before sunrise for the bright “Morning Star”.

If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at www.prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event.