Skywatcher's Guide: October and November 2018

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Stars and Constellations

In October, only a small portion of the spring sky is still visible at the beginning of the night.  The Big Dipper (Ursa Major) is low in the north-northwest.  As always, the last two stars in the bowl point to Polaris, our north star, in the Little Dipper (Ursa Minor).  You can also still follow the arc of the handle of the Big Dipper to Arcturus, the bright star in Boötes, now low in the west-northwest.  The summer constellations are also visible for a good portion of the night, starting the night in the middle of the sky.  The Summer Triangle is almost directly overhead, with Vega closest to the west-northwest, Deneb closest to the northeast, and Altair closest to the south.  The summer Milky Way is still prominently streaking across the sky, cutting from the northeast to the southwest.  Scorpius with the bright star Antares is now getting low in the southwest, and the nearby "teapot" of Sagittarius in the south-southwest.  The fall sky is now very prominent, taking up most of the eastern sky at the beginning of the night.  The "W" of Cassiopeia is easy to spot in the northeast, with Perseus just below.  The Great Square of Pegasus is up in the east, and Andromeda nearby in the east-northeast.  There is also a fairly bright star called Fomalhaut in the southeast, though its constellation Piscis Austrinus is not easy to distinguish.

In November, all but a few of the spring stars are now gone, and the summer constellations are starting to get lower in the west.  Deneb is the highest point of the Summer Triangle, with Vega below to the west, and Altair towards the southwest.  The brightest part of the summer Milky Way is now gone, but a good portion of it is still easy to distinguish.  Scorpius is now gone, but the "teapot" of Sagittarius is still above the horizon in the southwest.  The fall sky is now a little higher, but still in the eastern half of the sky.  We can now begin to see a few winter stars coming up along the eastern horizon, namely the bright Capella in the northeast and Aldebaran in the east-northeast.  Also look for the Pleiades (aka the Seven Sisters or Subaru) star cluster just above Aldebaran.

Interesting Stars Visible in October and November (during observatory hours)

Name / Designation Apparent Magnitude
(lower = brighter)
Distance
(light-years)
Notes
Arcturus -0.05 36.7  
Vega 0.03 25  
Capella 0.08 42  
Rigel 0.18 770  
Betelgeuse 0.45 427  
Altair 0.76 17  
Aldeberan 0.87 65  
Pollux 1.16 38  
Markab 1.25 140  
Deneb 1.25 3230  
Castor 1.58 52  
Polaris 1.97 431  
Alpheratz or Sirrah 2.07 97  
Mirach 2.07 199  
Algol 2.09 93 variable star
Enif 2.38 670  
Almak 2.1 / 5.0 & 6.3 355  triple star system w/ 64 yr orbit
Albireo 3.2 / 5.8 & 5.1 390 / 380  possibly a triple star system
Eta Cassiopeiae 3.5 / 7.4 19 480 yr orbit

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Solar System

Mercury will be visible in the evening sky from mid-October through mid-November.

Venus will be visible in the evening sky in early October, but passes between us and the sun later in the month.  By late November it will be visible again in the  morning sky.

Mars is prominent in the evening sky throughout October and November, moving through Capricornus and Aquarius.

Jupiter is visible in the early evening sky in October and early November, but will pass behind the sun in late November.

Saturn remains visible in the evening sky near Sagittarius and the Milky Way, but sets earlier each night.

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Calendar of Night Sky Events

Date Event
10/02/18 Last Quarter Moon.
10/08/18 Peak of Draconids meteor shower.
10/08/18 New Moon.
10/15/18 Appulse of Mercury and Venus. — Separated by 6.2°.
10/16/18 First Quarter Moon.
10/22/18 Peak of Orionids meteor shower.
10/23/18 Uranus at opposition. Best time to see this distant planet.
10/24/18 Full Moon.
10/26/18 Venus at inferior conjunction. — Between us and the sun.
10/28/18 Appulse of Mercury and Jupiter. — Separated by 3.1°.
10/31/18 Last Quarter Moon.
11/06/18 Mercury at greatest eastern elongation. — Visible after sunset.
11/07/18 New Moon.
11/15/18 First Quarter Moon.
11/17/18 Peak of Leonids meteor shower.
11/22/18 Full Moon.
11/25/18 Jupiter at conjunction. — Passing behind the Sun.
11/27/18 Mercury at inferior conjunction — Between us and the Sun.
11/27/18 Appulse of Mercury and Jupiter. — Separated by 0.4°.
11/29/18 Last Quarter Moon.

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Deep Sky

There are many deep sky objects we can see since the summer Milky Way is high in the sky.  There are many open star clusters that can be seen with only binoculars scanning this part of the sky.  For example we have the Butterfly Cluster (M6) and Ptolemy's Cluster (M7) near the tail of Scorpius.  Further north there is the Wild Duck Cluster (M11) in the faint constellation of Scutum between Sagittarius and Aquila.  There is also the asterism of the Coathanger between Aquila and Cygnus in the fainter constellation of Vulpecula.  Next, heading towards the west we can see the Coma Star Cluster in the constellation of Coma Berenices, which is even visible naked-eye.  The Pleiades (M45) will be visible later in the night, after midnight.

There are a several globular clusters we can see as well, as the center of our galaxy is the highest it gets for the year.  Near the bright star Antares in Scorpius lies the globular cluster M4.  In Sagittarius we also have the Teapot Cluster (M22).  Of course we have the famous Hercules globular (M13) high in the east.  Also, M15 is visible in the east near the head of Pegasus.

For nebulae, we have several in the plane of the galaxy, one of which is the Swan Nebula (M17) in Sagittarius, also known as the Omega Nebula.  There is also the Lagoon Nebula (M8) nearby and the North America Nebula (C20) further north in Cygnus.  For planetary nebulae we have the Ring Nebula (M57) in Lyra, the Dumbell Nebula (M27) in Vulpecula, and the Blue Snowball (C22) in Andromeda.

And now the galaxies:  Although the Big Dipper is getting lower in the sky, you may still be able to find some of the galaxies in this part of the sky.  We have the Whirlpool Galaxy (M51) and the Pinwheel Galaxy (M101) near the handle, and the Cigar Galaxy (M82) and Bode's Galaxy (M81) near the bowl.  The spectacular Andromeda Galaxy (M31) is now coming up in the northeast, along with the nearby Triangulum Galaxy (M33).

Interesting Deep Sky Objects to Observe during October and November (during observatory hours)

Designation Name Apparent Magnitude Apparent Size Distance
(light-years)
Type
Messier 45 Pleiades 1.6 110' 440 open cluster
Messier 31 Andromeda Galaxy 3.4 3° x 1° 2,900,000 spiral galaxy
Messier 42 Orion Nebula 4 85' x 60' 1400-1600 diffuse nebula
Messier 33 Triangulum Galaxy 5.7 67' x 42' 3,000,000 spiral galaxy
NGC 7293 Helix Nebula 7.3 16' 450 planetary nebula
Messier 27 Dumbbell Nebula 7.4 8' × 6' 1,250 planetary nebula
NGC 7009 Saturn Nebula 8 36" 2,400 planetary nebula
Messier 81 Bode's Galaxy 8.5 21' 1,200,000 spiral galaxy
Messier 57 Ring Nebula 8.8 1' 2,300 planetary nebula
Messier 82 Cigar Galaxy 9.5 14' 1,200,000 galaxy

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Frequently Asked Questions

What's the deal with this Planet 9 I keep hearing about?

For this story we need to go back a couple centuries to the year 1781.  This was the year that the planet Uranus was discovered.  The planets up to Saturn had been known since ancient times, since they are all visible to the naked eye.  But Uranus is right at the limits of human vision and so wasn't noticed until William Herschel pointed his telescope towards the ecliptic (the plane of our solar system) and found this tiny blue dot.  This made us wonder if there might be other planets out there waiting to be discovered.  20 years later, Ceres was discovered, followed by several other objects between Mars and Jupiter in what is now known as the asteroid belt.  By the 1840s it was realized that Uranus seemed to be moving not quite as predicted, which meant that there must be some other large unknown mass pulling on it.  Astronomers carefully calculated where this missing mass must be, and lo and behold when they pointed their telescopes there, they found Neptune.  Since this method worked so well, they thought they would try to do it again.

After many years and many attempts, Pluto was finally discovered in 1930.  But eventually they realized that Pluto was not big enough to have a noticeable effect on Neptune's motion, so the search continued.  There have since been many objects discovered past Neptune in what is now called the Kuiper Belt, but none turned out to have the large mass they were looking for.  The discovery of Eris in 2006, which is slightly more massive than Pluto, set off the debate about the definition of "planet", and brought our solar system back to 8 official planets.

Finally, in 2014, astronomers began to notice that some very distant objects, with orbits 10 or more times the size of Neptune's, showed some similarities.  Instead of being randomly distributed, they all seemed to have their perihelia aligned in the same direction.  Other objects discovered since then also seem to exhibit this pattern.  This clustering has been interpreted to mean that there is likely a large undiscovered planet lurking in the dark outer regions of our solar system.  Our estimation is that it is roughly Neptune-sized, but roughly 20-25 times farther away from the Sun.  That means it would be hundreds of times fainter than Neptune, so only our largest telescopes today would be able to observe it.  It may take several years, but astronomers are persistent, and we may soon find out if these predictions are true.

If you have any questions you'd like me to answer in the next issue of SWG, please let me know.  I'm also happy to take suggestions or comments, and also pictures if you'd like to send them.  Happy viewing!

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Bibliography

  • Cornelius, Geoffrey. The Starlore Handbook: an Essential Guide to the Night Sky. San Francisco, CA: Chronicle, 1997. Print.
  • Ottewell, Guy. Astronomical Calendar 2012. Raynham, Mass: Universal Workshop, 2011. Print.
  • Ottewell, Guy. Astronomical Calendar 2013. Raynham, Mass: Universal Workshop, 2012. Print.
  • Ottewell, Guy. The Astronomical Companion. 2nd ed. Raynham, Mass: Universal Workshop, 2010. Print.
  • Astronomy Magazine. February 2013. Volume 41, No 2.
  • Astronomy Magazine. February 2013. Volume 41, No 3.
  • Sky & Telescope. February 2013. Volume 125, No 2.
  • Sky & Telescope. March 2013. Volume 125, No 3.

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Date of publication:
2018