Skywatcher's Guide: April and May 2020

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Stars and Constellations

In April, the spring sky is now prominent in the east, along with the familiar Big Dipper.  The Big Dipper is high in the northeast, and the two stars at the end of the bowl can be used to find Polaris, our north star.  Also, the handle can be used to "arc to Arcturus", a bright star in the constellation Boötes. Next, Leo the lion is very high in the east, approaching the middle of the sky now, with the constellation Virgo just below.  The winter constellations are also visible, now in the west.  Taurus the bull is getting lower in the west, near Orion the hunter to the west-southwest.  Canis Major (the big dog), along with the bright star Sirius, is also getting low in the southwest.  Gemini the twins is a little higher in the west, along with Auriga the charioteer in the west-northwest and Canis Minor (the little dog) in the southwest.  The winter Milky Way is now getting lower in the west as well.  Far to the south we can see some constellations making up part of Jason's Argo Navis, which we only get to see briefly since it is so far south.  Finally, there is still a small portion of the fall sky still visible just for the first hour or so of the night.  Cassiopeia the queen is in the north-northwest, and Perseus the hero is in the northwest.

In May, the winter constellations are lower in the west, and Orion, Taurus, and Canis Major are already in the process of setting at the beginning of the night, along with Cassiopeia and Perseus to the northwest.  The spring constellations are higher now, and we can see the rest that weren't up this time last month.  Hercules is below Boötes in the east-northeast.  Some of the summer constellations are also getting ready to come up and will be visible a few hours after sunset.

Interesting Stars Visible in April and May (during observatory hours)

Name / Designation Apparent Magnitude
(lower = brighter)
Distance
(light-years)
Notes
Sirius -1.44 8.6  
Arcturus -0.05 36.7  
Vega 0.03 25  
Capella 0.08 42  
Rigel 0.18 770  
Procyon 0.4 11  
Betelgeuse 0.45 427  
Aldebaran 0.87 65  
Spica 0.98 262  
Pollux 1.16 38  
Deneb 1.25 3230  
Regulus 1.36 77 means "Little King"
Castor 1.58 52  
Polaris 1.97 431  
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
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 before sunrise during early April, will pass behind the Sun in early May, and then be visible after sunset in late May.

Venus is now getting lower in the western sky after sunset and will be lost in the glare of the Sun by the end of May.

Mars is getting higher in the morning sky before sunrise, moving through Capricornus and Aquarius.

Jupiter is in Sagittarius, rising earlier and earlier, eventually coming up before midnight in mid-May.

Saturn is in Capricornus, coming up shortly after Jupiter throughout April and May.

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Calendar of Night Sky Events

Date Event
04/01/20 First Quarter Moon.
04/03/20 Appulse of Mercury and Neptune. — Separated by 1.3°.
04/03/20 Appulse of Jupiter and Pluto. — Separated by 0.7°.
04/07/20 Full Moon.
04/14/20 Last Quarter Moon.
04/22/20 Peak of Lyrids meteor shower.
04/22/20 New Moon.
04/26/20 Uranus at conjunction. — Passing behind the Sun.
04/30/20 First Quarter Moon.
04/30/20 Appulse of Mercury and Uranus. — Separated by 0.3°.
05/04/20 Mercury at superior conjunction. — Directly behind Sun (anti-transit).
05/06/20 Peak of Eta Aquariids meteor shower.
05/07/20 Full Moon.
05/14/20 Last Quarter Moon.
05/17/20 Appulse of Jupiter and Saturn. — Separated by 4.7°.
05/22/20 Appulse of Mercury and Venus. — Separated by 0.9°.
05/22/20 New Moon.
05/29/20 First Quarter Moon.
05/30/20 Comet ATLAS at brightest (predicted). — In Taurus.

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Deep Sky

The winter Milky Way is now getting low in the west, but there are still several interesting objects we can see here.  The Pleiades (Seven Sisters, M45) is close to the west-northwest horizon right next to the Hyades (C41), which makes the face of Taurus the bull.  The constellation Auriga is a little bit higher, where we can see M36, M37, and M38, which are visible with binoculars.  The Double Cluster (C14) in Perseus is low in the north-northwest.  Higher in the sky we have the Beehive (Praesepe, M44) in Cancer the crab and Coma Berenices (Bernice's Hair) near the tail of Leo.

We are now beginning to see some globular clusters coming up in the east.  M3 is towards the east, in the constellation Boötes.  Nearby, the famous Hercules Globular (M13) is low to the east-northeast.

For nebulae, we have the spectacular Orion Nebula (M42) now now getting low to the west-southwest. This is the closest star-forming region to our solar system.  We also have some good planetary nebulae, which come from dying stars.  The Eskimo (C39) in Gemini is high in the west, the Owl (M97) in Ursa Major is high in the northeast, and the Ghost of Jupiter (C59) is to the south in the constellation Hydra.

And now the galaxies:  In Ursa Major to the north we have Bode's Galaxy (M81) and the Cigar Galaxy (M82), close enough to be seen together in a low-power telescope.  Nearby in the constellation Canes Venatici we have the Whirlpool (M51), which is a pair of colliding galaxies.  The Pinwheel Galaxy (M101) is also nearby near the handle of the Big Dipper.  Then the Sombrero Galaxy (M104) is in the southeast in the constellation Virgo.

Interesting Deep Sky Objects to Observe during April and May (during observatory hours)

Designation Name Apparent Magnitude Apparent Size Distance
(light-years)
Type
Messier 45 Pleiades 1.6 110' 440 open cluster
Messier 44 Beehive Cluster 3.7 95' 577 open cluster
Messier 42 Orion Nebula 4 85' x 60' 1400-1600 diffuse nebula
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 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 kind of astronomy can I do from home?

With most if not all observatories currently closed to the public, you may think you are out of luck when it comes to seeing certain astronomical objects.  But even without a big telescope, there are plenty of things we can see from our own backyards.

Constellations — See how many constellations you can recognize in the night sky.  If necessary, you can find a printable star chart online to help you know what is out.  (You would just need to put in your location, time, and date to get an accurate chart.)  Start with the easy ones and work your way up to the more difficult ones.  If you can recognize the constellations, or at least know how to find them, that is a great launch pad to finding many other things in the sky.

Planets — There are a few planets you can see with the naked eye, but unlike the constellations, they wander through the sky over time.  If your star chart is specific to the current year, it may have the planets' positions marked out.  If not, you may see a line called the Ecliptic.  (The constellations along the Ecliptic are known as the zodiacs.)  Along this path is where you may find the planets in the sky.  That is because our solar system is very flat, so they always line up with each other.  If you see a bright object in this part of the sky, it very well may be a planet.  Another thing you can look for is twinkling.  Typically stars twinkle and planets don't.  If you own a small telescope, you can easily make out the shape of the planets as well as details like the rings of Saturn, the moons of Jupiter, or the phase of Venus.

Our Moon — The Moon is not hard to find in the sky, but many people don't spend a lot of time looking at it.  (The Moon also follows the ecliptic across the sky, so that might help you find the planets as well.)  The best time to observe the Moon is when it is a crescent or quarter phase.  First, it will be dimmer and easier on your eyes.  Second, there will be more shadows on the surface to bring out detail.  Naked eye you can easily make out large features called maria, which are dark, smooth lava basins created by ancient impacts.  If you have binoculars or a small telescope, you can start to make out individual craters and mountains on the lunar surface.

Deep Sky Objects — There are a handful of these that can be seen with the naked eye.  A good star chart will have them marked.  The darker the sky is at your location, the better.  An easy object to start with is the Pleiades, or Seven Sisters star cluster in Taurus.  Other easy clusters are the Beehive in Cancer, and Coma Berenices, which is big enough they made it its own constellation!  The Orion Nebula is also visible to the naked eye, just below the hunter's belt.  For better viewing of these objects, you need binoculars or a small telescope.  These gather more light than your eye can, which makes the objects easier to see and brings out more detail as well.  There are many more objects you can see with only a little bit of enhancement.  Use the table just above this section to give you some targets.

Meteors — We do have a couple showers this time of year, so you very well may see a meteor or two if you go out on a dark night.  For meteors it is best to look with just your naked eye because you cannot predict where they will appear in the sky.  Go to a place where you don't have a lot of trees or buildings blocking your view, and just look up!  Also known as shooting or falling stars, meteors look like short-lived streaks of light in the sky.  You are more likely to see meteors during a shower, which is when Earth passes through the debris trail of a comet.

Satellites — A regular sight in the early evening or late morning sky, there are hundreds of satellites that can be seen naked eye.  These appear as points of light that work their way across the sky in a matter of minutes.  The reason we see them is that, just like our Moon, they are reflecting sunlight.  If you want to see a particular satellite (like the International Space Station or the Hubble Space Telescope), you can use an online database such as Heavens-above to tell you when they will fly over.  You just need to put in your location to get an accurate prediction.

So as you can see, there are many things in the sky that can be seen from your own backyard.  Big telescopes are great, but not necessary for casual observing.  In fact, many telescopes are complicated to set up and may even hinder your observing experience if you are doing it on your own.  So I would just suggest to go outside, take some time to let your eyes adjust to the dark, and see what you can see.  You'll be amazed at what's up there!

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:
2020