Skywatcher's Guide: October and November 2020
- Stars and Constellations
- Solar System
- Calendar of Night Sky Events
- Deep Sky
- Frequently Asked Questions
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)
|Alpheratz or Sirrah||2.07||97|
|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|
Mercury will be visible in the evening sky for the beginning of October. It will pass between us and the Sun later in the month, and then will be visible in the morning sky for most of November.
Venus continues to be visible in the morning sky before sunrise, gradually rising later and later.
Mars reaches opposition in mid-October, coming up right at sunset. As we get into November it will be rising before sunset.
Jupiter and Saturn are slowly getting closer together in Sagittarius. They will be directly south at sunset for the beginning of October, moving more towards the west each evening.
Note: The GRS is visible on the disk of Jupiter for 50 minutes before and after meridian transit time.
|Date||Meridian Transit Time|
|10/01/20||Mercury at greatest eastern elongation. — Visible in the evening after sunset.|
|10/08/20||Peak of Draconids meteor shower.|
|10/09/20||Last Quarter Moon.|
|10/13/20||Mars at opposition — Best time to see the red planet.|
|10/21/20||Peak of Orionids meteor shower.|
|10/23/20||First Quarter Moon.|
|10/25/20||Mercury at inferior conjunction. — Passing between us and the Sun.|
|10/31/20||Uranus at opposition. — Best time to see this gas giant.|
|11/08/20||Last Quarter Moon.|
|11/10/20||Mercury at greatest western elongation. — Visible in the morning before sunrise.|
|11/12/20||Appulse of Jupiter and Pluto. — Separated by 0.7°.|
|11/17/20||Peak of Leonids meteor shower.|
|11/21/20||First Quarter Moon.|
|11/30/20||Full Moon and Penumbral Lunar Eclipse.|
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
|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|
|Messier 3||(in Canes Venatici)||6.2||18'||34,000||globular cluster|
|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|
What's special about the OSIRIS-REx mission?
OSIRIS-REx is a mission that is currently orbiting asteroid Bennu and will be taking a sample of it here in October 2020 to bring back to the Earth. That alone is exciting in itself, but there are many other things worth noting about this mission. First, it is being run by the University of Arizona, with the principal investigator being professor Dante Lauretta from the Lunar and Planetary Lab right next door to Flandrau! So that is something to be proud of for us Wildcats. Next, Bennu is the smallest object so far to be orbited by a spacecraft. OSIRIS-REx had to perform some very delicate maneuvers to be able to achieve that. The orbital speed is only about 8 centimeters per second, in contrast to the International Space Station, which orbits the Earth at a speed of around 8 kilometers per second! Because Bennu is so small and the spacecraft is in such close proximity, it is able to get extremely detailed images of the surface. It has mapped the entire asteroid at a resolution of only 5 centimeters per pixel. Imagine using a spacecraft to help you find your keys!
Another exciting thing about this mission is that the sample that it will return is expected to be the largest sample return since the Apollo missions. The spacecraft will, without landing, reach out and grab between 60 grams and 2 kilograms of material from the surface. This will provide a treasure trove of data about the chemistry of the early solar system and possibly give hints about how life started on Earth. Bennu was chosen in part because it is known to be carbon-rich, and is though to have formed very early in our solar system's history. That era was extremely chaotic, with collisions happening much more frequently than they do today, and it is thought that perhaps asteroids such as Bennu may have delivered the chemicals necessary for life on our planet.
Missions like OSIRIS-REx are important not only for the science they perform in the moment, but they also help us practice for later missions that might use asteroids and comets for resources or for building an outpost for astronauts exploring our solar system. These activities sound a little sci-fi at the moment, but each step we take gets us closer to making that a reality.
The sample that OSIRIS-REx takes will be delivered to Earth in September 2023, after which it will be studied by scientists for decades to come. The spacecraft itself will remain in space, and could be sent on another mission yet to be determined. So there is still a lot to look forward to with this mission.
Connect with Flandrau on social media to stay up-to-date about the OSIRIS-REx mission and other space related topics. Specifically, look for our Science Snack series of videos, in which an episode all about OSIRIS-REx will be released in anticipation of the sample acquisition in late October.
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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- Sky & Telescope. March 2013. Volume 125, No 3.