Wednesday, July 31, 2019

Monthly Night Sky Report: August 2019

July turned out to be a spectacular month of stargazing for me in Utah.  I was able to go out to my favorite new dark sky site a couple of times as well as host a star party in honor of the 50th anniversary of Apollo 11 and the Moon landing.  At the star party, we were able to view Jupiter, the Great Red Spot, and its 4 moons.  We also looked at Saturn and its rings, a few star clusters including M7 (Ptolemy's Star Cluster), M13 (Hercules Globular Cluster), NGC 869 and NGC 884 (The Double Cluster), M92 (Globular Cluster similar to M13), and M57 (The Ring Nebula).  Thank you to everyone who was able to attend this star party and making it a great experience for me and everyone that was there!  I plan to do future star parties so be prepared to cancel all of your plans so you can attend!

August nights will continue to be warm making stargazing easier for those that don't enjoy the cold.  This month will bring the return of Mercury to the morning sky, the Perseid meteor shower, as well as the continued reign of Jupiter and Saturn throughout the night.

Mercury


Mercury will return to our morning sky this month, if only for a short time.  Mercury will rise about 45 minutes before the Sun on the 9th.  At this time, Mercury will shine at 0.0 magnitude, which is brighter than the nearest stars (Castor and Pollux), making it easier to spot.  As the month progresses, Mercury will sink closer to the Sun but will increase in magnitude.  By the 17th, Mercury will glow at -0.9 magnitude.  While waiting for Mercury to rise in the east before the Sun, you may notice the familiar stars of Orion.  For northern hemisphere stargazers, Orion heralds in the coming days of fall and winter.  By the end of the month, Mercury will once again be lost from our earthly view.   

Venus

Venus will be lost from our view during August, but will return in October just before sunset.

Mars

Like Venus, Mars will be lost from view throughout August but will return to view in October in our morning sky.

Jupiter

Jupiter will again be visible throughout most of the night during August.  It will shine brightly in the southeast and make its trek westward as each night marches on.  Jupiter will be found on the edge of the Milky Way band.  If you are lucky enough to have skies dark enough where you live or if you go to a dark sky site, use this giant planet as a guide to detect the faint band.  Be sure to check out the Galilean Moons of Jupiter which can easily be seen with a pair of binoculars and any size of telescope.  If you have a larger telescope, you can view the bands of Jupiter and even the Great Red Spot as well as the shadow of one of the moons as it transits this gas giant.  The crescent Moon will join Jupiter on the evening of the 9th this month.

Saturn

Saturn reached opposition in early July and will continue to be a great target for telescopes.  After viewing Jupiter for an hour or so, move over to the next largest planet in our solar system and get lost in the splendor of its rings.  Recall that Saturn will mark the other edge opposite of Jupiter of the Milky Way band that can be visible from a light polluted free sky.  The crescent Moon will join the ringed planet on the evening of the 11th.

Uranus
Neptune











The outer two planets can be best viewed through a telescope but can still be seen through a pair of binoculars.  Uranus should clear our Utah mountains around 1 in the morning Mountain Time.  It's best to view this planet slightly before dawn paints the sky, that way it will be high enough in the sky to focus on a little easier with your binoculars or telescope.  Uranus will rise slightly earlier with each passing night.

Neptune will clear the Utah mountains around 11 at night, but it's best to wait a few hours for this most distant planet to climb high in the sky before viewing.  Neptune will rise earlier with each passing night as the month ticks on.
 

Meteor Shower


This month brings the return of the Perseid meteor shower, one of the best meteor showers of the year.  Unfortunately, this year the Full Moon will be just two days after the peak date, washing out all but the brightest meteors.  The Perseid meteor shower produces more fireballs than any other meteor shower, so keep your eyes open for them!  The peak date is August 13th, but you can still try to catch this shower a day or two before the peak when the Moon will set earlier in the night.  To increase the number of meteors you see, get away from city lights and other forms of light pollution.  These meteors will appear to radiate from the constellation of Perseus which rises in the northeast around 1:30 in the morning Mountain Time.  This constellation can be found to the upper left of the Pleiades. 

Spot Me....🕵️  


So far, I've had you try and spot M44 - Beehive Cluster, M13 - Hercules Cluster, M19 - Globular Cluster, and the Galilean moons of Jupiter as well as some surface details of this giant planet.  Last month I had you look at the rings of Saturn and a comet.  I hope that you have been able to view at least one of these awesome sights.  If not, please try to do so!

Towards the end of July, I was able to look at the double cluster NGC 869 and NGC 884.  With a wide enough eyepiece, you can see both of these in the field of view.  These can be found in the constellation of Perseus where the Perseid meteor shower appears to radiate from.  You can use the constellation of Cassiopeia to help find the area of sky that contains the double cluster.  Draw an imaginary line using the middle star (Navi) and the bright star next to it (Ruchbah) on the funny part of the "W" in this constellation.  Follow this line towards Perseus which will be rising in the north-northeast just after sunset.  If you reach the star Miram (magnitude 3.77 star in Perseus) then you have gone too far.  This double cluster is about 7500 light years away.  The double cluster can be seen by the unaided eye if you get away from city lights.  Any size of telescope will bring out the stars in each of these star clusters.

Since we are already using Cassiopeia to star hop to find the double cluster, let's continue to use this constellation to find our nearest neighboring galaxy, Andromeda (M31).  This galaxy is 2.5 million light years from Earth and is the furthest object that can be seen by the unaided eye.  You will have to be at a place free of light pollution to detect it, but you have to use inverted vision to see it.  This means that you can't look directly at its location but just off to the side.  It will appear as a fuzzy blob, like most deep sky objects.  Use the two stars in Cassiopeia that make up the funny part of the "W" and follow them towards the constellation of Andromeda, which is rising in the northeast just after sunset.  August is a prime time to try to catch a glimpse of this neighbor since it is still warm outside at night and most people are still out of school and wanting to enjoy the remaining summer.  Take a look at my picture at the end of this post; "Andrew vs. the Cosmos."  The brightest object in the sky is Andromeda! 

As always, let me know what you see!

Monthly Breakdown


August 07:  First Quarter Moon 🌓
August 09:  Moon and Jupiter pass within 2°
August 12:  Moon and Saturn pass within 0.5°
August 13:  Perseid Meteor Shower Peaks
August 15:  Full Moon 🌕
August 17:  Moon and Neptune pass within 4°
August 21:  Moon and Uranus pass within 5°
August 23:  Last Quarter Moon 🌗
August 30:  New Moon 🌑

Think About This....💡


Since August brings about one of the best meteor showers of the year, when not obscured by the moon's brightness, I thought I would talk about these meteor showers, why we have them, and how we can predict when they occur.  On a related topic, asteroids have been in the news more frequently when they have a "close encounter" with the Earth.  I will also discuss the reasons why these asteroids go undetected until after they zip by our planet.

While you are out stargazing, you have likely noticed a "shooting star" and have probably thought "Ohh, pretty!" or shout out to your friends, "There's one!" but you may have never wondered what they actually are, where they come from, or why on some nights you see more shooting stars than on other nights.  These "shooting stars" are actually small pieces of dust or dirt that are usually no bigger than a grain of sand burning up in the atmosphere.  Occasionally, a larger chunk of material will enter the atmosphere to burn up, creating a large fireball in the sky.  The Perseid meteor shower this month is famous for producing more of these fireballs than any other meteor shower.  There are many videos online of these fireballs such as this one, recorded over Australia earlier this year.

On a typical night, you can see an average of 5 to 10 meteors per hour.  This number increases, sometimes dramatically, during a meteor shower.  The Perseid meteor shower for example, has a maximum rate of 110 meteors per hour if the Moon does not interfere and you are able to get to a dark sky site.   As a comet travels towards the inner solar system, it heats up and begins to melt (it is a dirty snowball afterall), leaving a trail of dirt, rock, and dust.  This rate goes up because during a meteor shower, the Earth is traveling through the debris left behind from a comet.  The parent comet to the Perseid meteor shower this month is Swift-Tuttle.  Since it is known how the Earth travels around the Sun and where the debris from the comet tail resides in the orbit, each meteor shower can be predicted with ease.

NASA and other agencies are always on the lookout for comets, asteroids, and other objects close to Earth.  These are known as near Earth objects, or NEO's.  Detection of comets is much easier than the detection of asteroids.  As a comet moves closer to the Sun, it begins to heat up and melt, giving off gases which creates a tail that can be easily seen by telescopes.  Comets can also be seen by the unaided eye when they pass close enough to Earth, creating quite a spectacle to look at.

Asteroids on the other hand are much harder to detect.  Many times, they are detected as they fly by the Earth or even after it has passed us by.  Asteroids are typically smaller than comets, at least the ones that are classified as NEO's.  Since they are small, usually less than 20 meters in diameter, they have to be very close to the Earth to see.There are even times when the asteroid is on the daylight side of the Earth, making it impossible to see until it is too late.  The larger the asteroid is, the sooner it can be detected and the more advanced the warning can be.                   

Stay tuned for more exciting news and events!                      



Now get outside and look up!
Planet images taken by NASA.
Andrew vs. the Cosmos taken by Jeff Greenland.

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