The University of Arizona

Skywatcher's Guides

Flandrau’s Observatory is operated entirely by volunteers. Please call ahead to see if the observatory is open (generally Thurs-Sat 7pm – 10pm). Our astronomer volunteers will help you experience the 16-inch telescope as well as answer your questions about the night sky.

Written by: Lucas Snyder (Flandrau Planetarium Operator)
Images contributed by: Tim Van DevenderAlistair Symon (Flandrau Telescope Operators), Nine Planets, and Students for the Exploration and Development of Space (SEDS)

Navigationphoto by Tim Van Devender

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

 

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

 

Mirach

2.07

199

 

Denebola

2.14

36.2

 

Enif

2.38

670

 

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

 

Solar System

Mars is passing behind the sun and won't be visible.

 

Venus reaches its highest sunset altitude in early June and begins sinking back towards the sun.  It will be travelling through Cancer the Crab.

 

Jupiter starts off high in the west, but is slowly getting closer to the sun each night.  It is now between Cancer and Leo.

 

Saturn gets higher in the east each night. It is still hovering near the claws of Scorpius.

 

Mercury emerges from the glare of the sun in mid June and will be visible in the morning before sunrise. But by mid July it will be lost again as it heads behind the sun.

 

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

06/05/15

09:55 PM

06/20/15

07:25 PM

06/27/15

08:15 PM

07/02/15

07:25 PM

07/04/15

09:04 PM

07/09/15

08:14 PM

 

Calendar of Night Sky Events

 

06/02/15

Full Moon.

06/06/15

Venus at greatest eastern elongation. Highest sunset position.

06/07/15

Peak of Daytime Arietids meteor shower.

06/09/15

Last Quarter Moon.

06/14/15

Mars at conjunction. Behind the sun.

06/16/15

New Moon.

06/21/15

Earth at northern solstice. Beginning of summer.

06/24/15

First Quarter Moon.

06/24/15

Mercury at greatest western elongation. Visible in the morning before sunrise.

06/30/15

Venus and Jupiter in conjunction. Separated by only 0.3°.

07/01/15

Full Moon.

07/06/15

Pluto at opposition. Best time to look for this dwarf planet, although it is only 14th magnitude.

07/06/15

Earth at aphelion. Our farthest distance from the sun.

07/06/15

Comet Pan-STARRS at brightest. Will be close to the sun, but perhaps visible right after sunset with binoculars.

07/08/15

Last Quarter Moon.

07/15/15

New Moon.

07/15/15

Mercury and Mars in conjunction. Separated by only 0.1°.

07/23/15

Mercury at superior conjunction. Behind the sun.

07/23/15

First Quarter Moon.

07/25/15

Ceres at opposition. Best time to look for this dwarf planet.

07/31/15

Full Moon.

 

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

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 33

Triangulum Galaxy

5.7

67' x 42'

3,000,000

spiral galaxy

NGC 7009

Saturn Nebula

8

36"

2,400

planetary nebula

Messier 81

Bode's Galaxy

8.5

21'

1,200,000

spiral galaxy

Messier 82

Cigar Galaxy

9.5

14'

1,200,000

galaxy

 

Frequently Asked Questions – How do we measure distance in space?

Determining how far away something is in space is not as simple as using a (really big) ruler.  We need to find ways to calculate the distance using other measureable quantities.

 

For objects within our solar system, we can use radar to measure distance.  Radio waves bounce off objects, so by measuring the time it takes to reflect back to us, we can know their distance very exactly.  It would be great if we could use this for everything, but the problem is that the farther the object, the longer we have to wait.  Plus, the farther the radio signal travels the weaker it gets, so by the time it gets back we may not be able to detect it.

 

The next method we can use is called parallax.  This involves measuring how much something appears to move in the sky throughout the year.  You can demonstrate this for yourself by alternating blinking your right eye and then your left.  Objects far away from you seem to stay still, while objects close to you seem to jump back and forth.  Similiarly, as the earth goes around the sun, we are looking at objects from different positions, and the closer stars will appear to move back and forth compared to the farther ones.  This requires very accurate and precise measurements of positions throughout the year, since even the closest stars to us appear to move by less than one arcsecond in the sky.  It can also be complicated by the fact that stars are not necessarily stationary relative to our sun, so any relative motion would have to be subtracted out before parallax can be determined.  This method has its limits, too, since our instruments have only so much precision they are capable of.

 

Next, we can use something called a standard candle.  This is a particlar type of object for which we know how much light is being emitted.  Since we know the apparent brightness decreases with the square of the distance, by measuring how much light we receive, we can calculate the distance.  Certain types of variable stars and supernovae can be used as standard candles.  The limitation of this method is that there may not be a standard candle available to us in every object we want to study.

 

Finally, we can use redshift.  Since the 1920s we have known that the universe is expanding, and that the farther the object, the faster it appears to be moving away from us.  Just like how a train horn changes pitch as the train passes you, light from distant galaxies changes color depending on its speed relative to our Milky Way.  The faster it moves, the more red they appear as the lightwaves get stretched out.  So the redshift of a distant galaxy tells us the speed at which it is moving away from us, and indirectly the distance as well.  This method is the least accurate, so this would only be used if no other method is available.

 

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!

 

Table of Images (Click on an image to expand)

Sketches and Images - Image Credit (Tim Van Devender)

Mars

Mars

Saturn

Saturn

Jupiter

Jupiter

The Moon

The Moon

Jupiter and Io Moon Shadow

Jupiter and Io Moon Shadow

Messier 45 (Pleiades)

M45

NGC 884 and NGC 869 - Perseus Double Cluster

NGC 884 and NGC 869 - Perseus Double Cluster

NGC 2024 - The Horsehead and Flame Nebulae

NGC 2024 - The Horsehead and Flame Nebulae

NGC 2237 - The Rosette Nebula

NGC 2237 - The Rosette Nebula

NGC 2264

NGC 2264

Images from Alistair Symon
Messier 27 (Dumbbell Nebula)

M27

Mssier 31 (Andromeda Galaxy)

M31

Messier 33 (Triangulum Galaxy)

M33

Messier 45 (Pleiades)

M45

Messier 57 (Ring Nebula)

M57

Images from Nine Planets
Jupiter

Jupiter

The Moon

The Moon

Images from SEDS
Messier 13 (Hercules Globular Cluster)

M13

Messier 15

M15

Messier 27 (Dumbbell Nebula)

M27

Messier 31 (Andromeda Galaxy)

M31

Messier 33 (Triangulum Galaxy)

M33

Messier 44 (Beehive Cluster)

M44

Messier 45 (Pleiades)

M45

Messier 57 (Ring Nebula)

M57

NGC 7009 (The Saturn Nebula)

NGC 7009

NGC 7293 (The Helix Nebula)

NGC 7293

 

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.