Skywatcher's Guide: February and March 2018

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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)
Distance
(light-years)
Notes
Sirius -1.44 8.6  
Arcturus -0.05 36.7  
Capella 0.08 42  
Rigel 0.18 770  
Procyon 0.4 11  
Betelgeuse 0.45 427  
Aldeberan 0.87 65  
Pollux 1.16 38  
Markab 1.25 140  
Regulus 1.36 77 means "Little King"
Castor 1.58 52  
Polaris 1.97 431  
Alpheratz or Sirrah 2.07 97  
Mirach 2.07 199  
Algol 2.09 93 variable star
Denebola 2.14 36.2  
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

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Solar System

Mercury is passing behind the sun in mid February, but during mid March it will be visible in the evening after sunset.

Venus is still lost in the glare of the sun during February, but my mid March it will be visible in the evening after sunset.

Mars rises earlier and earlier each morning, getting higher and higher in the southeast.

Jupiter rises earlier and earlier each morning within the constellation of Libra, eventually rising at midnight at the end of March.

Saturn rises earlier each morning in the constellation of Sagittarius.

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Calendar of Night Sky Events

Date Event
02/07/18 Last Quarter Moon.
02/15/18 New Moon and Partial Solar Eclipse. — Unfortunately not visible from North America.
02/17/18 Mercury at superior conjunction. — Passing behind the sun.
02/21/18 Appulse of Venus and Neptune. — Separated by 0.5°.
02/23/18 First Quarter Moon.
02/25/18 Appulse of Mercury and Neptune. — Separated by 0.4°.
03/01/18 Full Moon.
03/03/18 Appulse of Mercury and Venus. mdash; Separated by 1.1°.
03/04/18 Neptune at conjunction. — Passing behind the sun.
03/09/18 Last Quarter Moon.
03/15/18 Mercury at greatest eastern elongation. — Visible in the evening after sunset.
03/17/18 New Moon.
03/19/18 Appulse of Mercury and Venus. mdash; Separated by 3.8°.
03/20/18 Earth at northward equinox. — Beginning of our Spring.
03/24/18 First Quarter Moon.
03/28/18 Appulse of Venus and Uranus. mdash; Separated by 0.07°.
03/31/18 Full Moon.

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Deep Sky

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
(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 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

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Frequently Asked Questions

When is the best time to see meteors?

Meteors, also known as falling or shooting stars, are a fun thing to see when you are out at night.  They can happen randomly any time of night and any time of year.  But there are certain times and dates that you have a higher probability of seeing meteors.

First off, what is a meteor?  It is something usually very small, roughly the size of a grain of sand.  When it enters our atmosphere, it is heated by impacts with air molecules so that it glows brightly in the sky until it vaporizes and disappears.  Meteors are usually visible 30-75 miles above the ground.  Larger objects, several centimeters across (or larger), may not completely vaporize, leaving a fragment that impacts the ground.  Over the course of a year, a total of 15000 tonnes of space debris is estimated to fall to the earth.

Meteoroids, which is what these particles are called while they are still in space, can come from comet tails, asteroid collisions, or just primordial material left from the formation of our solar system.  These particles orbit the sun just like the planets and asteroids, but are much more easily perturbed in their orbits due to the gravity of any nearby larger objects.  There are certain locations where these particles tend to clump up, and if the earth goes into one of these areas, this is when we see a meteor shower.

The three biggest meteor showers we have every year are the Perseids in mid August, the Quadrantids in early January, and the Geminids in mid December.  Showers are named for the area of the sky they appear to be coming from, not where they become visible.  Meteors can appear anywhere in the sky, but they have a trajectory that can be usually be traced back to a particular constellation.

Finally, each meteor shower has a particular peak date and time when they are predicted to be the most visible around the earth.  But for a particular location, the apparent peak is always between midnight and 6am.  This is because of the direction of spin of the earth and the direction of our orbit around the sun.  I like to compare it to driving down the highway: you are more likely to see things hitting the front windshield than the back.  In the early morning the spin and the orbital motion are in the same direction, so you are more likely to see meteors at that time.  Meteors still hit us after sunrise, but would be lost in the glare of daylight.

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