Skywatcher's Guide: June and July 2018

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Stars and Constellations

In June, the spring sky is now prominent overhead, along with the familiar Big Dipper.  The Big Dipper is high in the north, 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. Then Hercules is just below towards the east.  Next, Leo the lion is very high in the west, with the constellation Virgo nearby to the south.  A few winter constellations are still visible, now vert low in the west.  Castor and Pollux, the heads of Gemini the twins, are the most prominent, to the west-northwest.  The summer sky is now just starting to come up at the beginning of the night.  The bright star Vega in the constellation Lyra the harp is towards the east-northeast.  In the southeast we have the constellation Scorpius the scorpion, with the bright star Antares.  Further to the south we can also see the constellations of Centaurus and Lupus the wolf right along the horizon.

In July, the last of the winter constellations are now gone, and the spring constellations are beginning to head to the west.  The summer constellations are now mostly up in the east.  We can easily see all three stars in the Summer Triangle, Vega being the highest in the east-northeast, Deneb a little lower to the northeast, and Altair to the east.  To the southeast we can see the Teapot of Sagittarius near the tail of Scorpius.  Also, to the north-northeast we can see the W of Cassiopeia the queen.

Interesting Stars Visible in June and July (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  
Procyon 0.4 11  
Altair 0.76 17  
Spica 0.98 262  
Pollux 1.16 38  
Markab 1.25 140  
Deneb 1.25 3230  
Regulus 1.36 77 means "Little King"
Castor 1.58 52  
Polaris 1.97 431  
Alpheratz or Sirrah 2.07 97  
Denebola 2.14 36.2  
Enif 2.38 670  
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 passing behind the sun in the beginning of June, but will become visible again later in the month.  It will be highest in the sky after sunset in mid-July, but will quickly descend again by the end of the month.

Venus continues getting higher and higher after sunset throughout June and July.

Mars comes up earlier and earlier, eventually rising at sunset by late July.

Jupiter remains prominent throughout June and July but will be setting earlier each morning.

Saturn is rising earlier each night, and by late June will be visible right after sunset.

Jupiter Great Red Spot Transits during June and July (when the Flandrau dome is open)

Note: The GRS is visible on the disk of Jupiter for 50 minutes before and after meridian transit time.

Date Meridian Transit Time
06/08/18 07:05 PM
06/15/18 07:51 PM
06/22/18 08:37 PM
06/29/18 09:24 PM
07/21/18 07:37 PM
07/28/18 08:25 PM

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Calendar of Night Sky Events

Date Event
06/05/18 Mercury at superior conjunction. — Hidden behind the sun.
06/06/18 Last Quarter Moon.
06/07/18 Peak of Daytime Arietids meteor shower.
06/13/18 New Moon.
06/20/18 First Quarter Moon.
06/21/18 Earth at northern solstice. — Beginning of our Summer.
06/27/18 Saturn at opposition. — Best time to see this ringed planet.
06/27/18 Full Moon.
07/06/18 Last Quarter Moon.
07/06/18 Earth at aphelion. — Our farthest distance from the Sun.
07/11/18 Mercury at greatest eastern elongation. — Visible in the evening after sunset.
07/12/18 Pluto at opposition. — Best time to look for this dwarf planet.
07/12/18 New Moon.
07/19/18 First Quarter Moon.
07/26/18 Mars at opposition. — Best time to see the red planet.
07/27/18 Full Moon.

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Deep Sky

There are several open star clusters we can see this time of year. First, Coma Berenices (Bernice's Hair) is high in the west near the tail of Leo. Next, there is the Ptolemy cluster (M7) and the Butterfly (M6) in the southeast near the tail of Scorpius. Also nearby is the Wild Duck (M11) in the constellation of Scutum.

Now that the Milky Way is coming up, there are several globular clusters we can see. M3 is high in the west, in the constellation Boötes. Nearby, the famous Hercules Globular (M13) is high in the east. We also have M5 high in the south in the constellation of Serpens. Finally, for those with a clear horizon, the amazing Omega Centauri (C80) is visible low to the south.

For nebulae, we can see the Swan (M17), the Lagoon (M8), and the Trifid (M20) to the southeast in the constellation Sagittarius. The Eagle (M16) is nearby in the constellation of Serpens. The North America nebula is also in the northeast in Cygnus. For planetary nebulae, we have the Owl (M97) in Ursa Major high in the northwest. We also have the Dumbbell (M27) in the west-northwest in the constellation of Vulpecula and the Ring (M57) nearby in Lyra.

And now the galaxies: In Ursa Major to the northwest 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 Southern Pinwheel (M83) is to the southwest in the constellation Hydra. The Sombrero Galaxy (M104) is nearby in the constellation Virgo.

Interesting Deep Sky Objects to Observe during June and July (during observatory hours)

Designation Name Apparent Magnitude Apparent Size Distance
(light-years)
Type
Messier 44 Beehive Cluster 3.7 95' 577 open cluster
Messier 3 (in Canes Venatici) 6.2 18' 34,000 globular cluster
NGC 7009 Saturn Nebula 8 36" 2,400 planetary nebula
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

How many objects have we explored in our solar system?

I'm sure you've seen images from Mars, Jupiter, or Saturn, and maybe a moon or an asteroid or two.  But just how many objects have we actually visited?  Well, humans have only been to the Earth (obviously) and our moon, so these are the only places we've experienced first hand.  Our spacecraft have acted as robotic ambassadors, sending pictures and other data back from far away places that humans may not visit for many generations to come.

Space exploration began in 1957 with the launch of Sputnik 1, which orbited the Earth giving us our first data on the Earth's upper atmosphere.  Less than two years later, Luna 1 flew past the moon, discovering that it did not have a magnetic field.  In 1961, Venera 1 became the first spacecraft to fly by Venus, although it failed to return any data.  Mariner 2 a year later was the first successful Venus mission.  Mars 1, the first spacecraft to fly past Mars in 1963, also failed to return data, so it was Mariner 4 in 1965 that gave us our first closeup view of the red planet.  Next we visited Jupiter with Pioneer 10 in 1973.  Mariner 10 followed with a flyby of Mercury in 1974. Helios-A was our first spacecraft to study the sun (though still from about the distance of Mercury) in 1975. Then we visited Saturn with Pioneer 11 in 1979.  Voyager 2 visited the two remaining planets - Uranus in 1986 and Neptune in 1989.

Our first cometary encounter came in 1985 when ICE flew through the tail of Giacobini-Zinner.  And our first flyby of an asteroid was when Galileo passed Gaspra in 1991.  Ceres was the first dwarf planet we visited with the Dawn spacecraft in 2015.  New Horizons passed Pluto later in 2015, making it the farthest object visited so far by our spacecraft, although New Horizons is scheduled to visit another small Kuiper Belt object in 2019 before heading to interstellar space.

In summary, we have visited the sun, all eight planets, two dwarf planets, 11 asteroids, 8 comets, and (by my count) 54 moons, which brings our total to 84 objects.  But there are thousands or even millions more out there waiting to be explored.

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