Skywatcher's Guide: February and March 2020
- Stars and Constellations
- Solar System
- Calendar of Night Sky Events
- Deep Sky
- Frequently Asked Questions
Stars and Constellations
In February, the center of the Milky Way is well below the horizon, but there is still a good portion of our galaxy we can see streaking high across the sky. The fall sky is still prominent in the west. The "W" of Cassiopeia is high in the northwest. In the absence of the Big Dipper (part of our spring sky) Cassiopeia can be used to locate the north star: The top (open side) of the "W" faces to the north, so in that direction look for a star about the same brightness as the main stars in Casssiopeia, and that will most likely be Polaris. The Big Dipper is beginning to come up again, but it is likely to be hidden behind trees and mountains along the horizon. Next, the Great Square of Pegasus is getting low in the west. Andromeda is just above that, with Perseus even higher, nearly in the middle of the sky. Finally, the winter sky is now getting very high in the east. Taurus the bull with the bright star Aldebaran is very high (near Perseus) along with the Pleiades (aka the seven sisters or Subaru) star cluster. Auriga the charioteer with the bright star Capella is very high as well, slightly more to the northeast. Gemini the twins is just below that in the east, and Canis Minor (the little dog) with the bright star Procyon is just below. Orion the hunter is up in the southeast, with his easily recognizable belt, and Canis Major (the big dog) is just below.
In March, the winter portion of the Milky Way continues to streak across the sky. The fall constellations are now getting low in the west, with Pegasus now partly below the horizon. The winter constellations are now in the middle of the sky, and some of the spring constellations are beginning to come up. Leo the lion is just above the horizon in the east, and the Big Dipper (Ursa Major) is now up in the northeast.
Interesting Stars Visible in February and March (during observatory hours)
|Name / Designation||Apparent Magnitude
(lower = brighter)
|Regulus||1.36||77||means "Little King"|
|Alpheratz or Sirrah||2.07||97|
|Almak||2.1 / 5.0 & 6.3||355||triple star system w/ 64 yr orbit|
|Eta Cassiopeiae||3.5 / 7.4||19||480 yr orbit|
Mercury is visible in the evening sky for the first half of February, but passes between us and the Sun by the end of the month. Then it will reappear in the morning sky in the second half of March.
Venus is still high in the evening sky after sunset, reaching its highest point at the end of March.
Mars is getting higher in the east each morning, moving from Ophiuchus, through Sagittarius, and into Capricornus.
Jupiter rises earlier and earlier each morning near the handle of the teapot in Sagittarius.
Saturn is now visible in the morning before sunrise, rising earlier each day between the constellations of Sagittarius and Capricornus.
|02/01/20||First Quarter Moon.|
|02/10/20||Mercury at greatest eastern elongation. — Visible in the evening after sunset.|
|02/15/20||Appulse of Mercury and Neptune. — Separated by 5.8°.|
|02/15/20||Last Quarter Moon.|
|02/18/20||Moon occults Mars. — The red planet is hidden for about an hour.|
|02/25/20||Mercury at inferior conjunction. — Between us and the Sun.|
|03/02/20||First Quarter Moon.|
|03/08/20||Neptune at conjunction. — Passing behind the sun.|
|03/08/20||Appulse of Venus and Uranus. — Separated by 2.2°.|
|03/16/20||Last Quarter Moon.|
|03/19/20||Earth at northward equinox. — Beginning of our Spring.|
|03/20/20||Appulse of Mars and Jupiter. — Separated by 0.7°.|
|03/21/20||Appulse of Mars and Pluto. — Separated by 0.01°.|
|03/23/20||Mercury at greatest western elongation. — Visible in the morning before sunrise.|
|03/24/20||Venus at greatest eastern elongation. — Visible in the evening after sunset.|
|03/31/20||Appulse of Mars and Saturn. — Separated by 0.9°.|
The winter Milky Way is now prominent in the sky. There are many spectacular deep sky objects we can see now. Starting with open clusters, we first have the Pleiades (Seven Sisters, M45) nearly in the middle of the sky. Next to that, the Hyades cluster (C41) makes up the face of Taurus the bull. Also nearby, the constellation of Auriga contains M36, M37, and M38, which are visible with binoculars. We also have Perseus's Double Cluster (C14) still fairly high in the northwest, and the Beehive (Praesepe, M44) up in the east.
This is not a good time of year to see globular clusters, as most of them are concentrated in the summer sky. The brightest one we can see now is M79 below Orion in Lepus the hare, but it is nearly 8th magnitude.
For nebulae, we have the spectacular Orion Nebula (M42) now prominent in the south. This is the closest star-forming region to our solar system. We also have some good planetary nebulae, which come from dying stars. The Blue Snowball (C22) in Andromeda is towards the west, the Eskimo (C39) in Gemini is high in the east, and the Owl (M97) in Ursa Major is low in the northeast.
And now the galaxies: Our neighbor the Andromeda Galaxy (M31) is now heading towards the west and is visible on dark nights with the naked eye. Also nearby is the Triangulum Galaxy (M33), visible with binoculars. In Ursa Major to the northeast we have Bode's Galaxy (M81) and the Cigar Galaxy (M82), close enough to be seen together in a low-power telescope.
Interesting Deep Sky Objects to Observe during February and March (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 44||Beehive Cluster||3.7||95'||577||open cluster|
|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|
|Messier 81||Bode's Galaxy||8.5||21'||1,200,000||spiral galaxy|
|NGC 3242||Ghost of Jupiter||8.6||25"||1400||planetary nebula|
|Messier 82||Cigar Galaxy||9.5||14'||1,200,000||galaxy|
What are some cool facts about the Moon?
Humans have been fascinated with our Moon since before the dawn of civilization. We keep track of its phases and create art inspired by it. But besides being a beautiful sight in our sky, there is a lot of cool science we have learned and continue to learn about our celestial companion.
First, its size. Out of the hundreds of moons in our solar system, our Moon ranks fifth (after Ganymede, Titan, Callisto, and Io). Relative to the size of its parent planet, though, it is the largest, at 1/4 the diameter of Earth. (The next is Triton at only 1/18 the diameter of Neptune.) And viewed from the surface of its parent planet, our Moon has the second largest angular size, at about 32 arcminutes (after Io at about 35 arcminutes). (Please note I am not including the dwarf planets or any asteroids in this comparison.)
Our Moon also appears the brightest of any Moon as viewed from its parent planet. Even though Io has a higher albedo, its distance from the Sun means there is less sunlight to reflect. However, what many people don't realize is that our Moon only reflects about 12-13% of the sunlight that hits it, which would be comparable to worn asphalt. It just appears so bright to us because of its proximity and the contrast with the surrounding blackness of space. (Notice it doesn't look so bright when you can see it in the daytime.)
Our Moon is locked in synchronous rotation as it goes around the Earth, meaning it always keeps the same face towards us. This is not uncommon in our solar system; it happens due to tidal forces slowing the moons down over time. However, that lock is not perfect. Because the Moon's orbit is slightly elliptical and not aligned with our equator, the Moon appears to wobble in our sky. This is called libration, and it allows us to see about 59% of the Moon's surface throughout the month.
The Moon is the farthest that humans have travelled to in space (so far). 24 people have flown to the Moon, and 12 actually set foot on the surface. But besides humans, we have also sent our robotic spacecraft up there, and it now holds more manmade material than any other celestial body other than Earth. In total there are over 200 tons of material that we have left on the Moon. Conversely, we have brought back about 800 pounds of Moon rocks, which is by far the most material we have returned from anywhere in the solar system.
It is interesting that Moon rocks have very similar composition to rocks we find on the Earth. It is believed that the Moon actually formed when a Mars-sized planet named Theia collided with the early Earth as our solar system was forming. This sent a lot of debris into orbit which eventually coalesced due to gravity.
While the Moon's formation was likely very violent, we are fortunate to have this celestial companion. It helps to stabilize the Earth's axis so that our seasons don't fluctuate very much over time. And plus it is a key component to many animal life cycles, guiding them in great migrations and providing light for hunting at night. The Moon will continue to be an exciting place to learn about and potentially even visit in the future.
These are some of the facts about the Moon that I find cool or interesting, but if you have any others, please feel free to send them to me via email!
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!
- 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.