Following the Arrows

   A few years ago one of my “Scope on the Skies” columns was about the Juno mission to Jupiter, but the focus was more or less about how the Juno spacecraft used solar power as far away as Jupiter, the Planetary Society and their Light Sail project, and a SciFi story by Isaac Asimov. However for me the most interesting part writing the column was learning about large concrete arrows scattered around our country. These turned out to be directional arrows used by pilots in the days of daytime flying and no radar for travel guidance. Arrows later had Beacons with lights, then radio signals were added. Eventually these were replaced with more advanced radios and radar.

   So we loaded the truck, gassed up, and drove from Lee’s Summit, MO southwest across Kansas to near the city of Haysville, KS to find the arrow near there. It was located along a dirt county road and nearly buried in grass and bushes. However the arrow was intact but whatever color it was painted had faded away.
      (37°32’04.7″N 97°25’11.9″W)

   Then we drove further south to near the Oklahoma, Kansas state line to the city of Anthony, KS. A couple of miles west from the city is the Anthony Airport and just off the road near the end of the runway is an Arrow and a Beacon.
      (37°09’06.8″N 98°04’37.0″W)

   Click here to download the ‘Scope’ column about the Arrows.

   
   
   
   
   
   


   
   
   

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July Moon at Descending Node

   Friday July 3rd the 11-day old waxing gibbous Moon crosses the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.

   On the date of the descending node the waxing gibbous Moon will be over the southern horizon around local time for sunset. Look for the Moon to be about 9-10o from the heart of Scorpius the Scorpion, the reddish star Antares.

   
   
   
   
   

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Thin Moon on the Move

   Sunday June 21st, on the other side of the Earth from the U.S.A., the new Moon will be passing between the Earth and the Sun giving that side of the world an annular solar eclipse.
   About 1/2-day later the just past new Moon, an 0.80-day young thin waxing crescent Moon may be seen just above the western horizon at sunset local time. If you see the Moon look closely for a star-like object just to the left from the Moon. This is the inner planet Mercury.
   If you miss the Moon and Mercury on Sunday evening wait until Monday evening June 22nd to see the still thin 1.85-days old waxing crescent Moon near one of the Gemini ‘Twin’ stars, Pollux.
   Not had enough? On Tuesday June 23rd the 2.80-days young waxing crescent Moon will be near M44, the Beehive Cluster.
   Any of these conjunctions will look great in binoculars.

   
   
   

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I Should’ve Gone to Mars!

   Let’s face it. I am a ‘closet geographer’! Can you say Geomorphology? That is my passion when not looking skyward. I am fascinated by landforms and how they came to looking the way they do now. What were the weathering and erosional process that were involved and how did the patterns of those process do what it did? And that leads into this blog, sort of a repeat of a previous blog about taking a road trip on Mars, and two more recent blogs about this trip. This time a road trip, or actually an air trip to my brother’s home in Sun City Arizona, a northwest suburb of Phoenix.
   So imagine the diverse landforms you could see along the way either from the ground in a car or by plane as I did traveling across the United States from my home in Lee’s Summit, Missouri to my brother’s place near Phoenix Arizona. From the wooded and hilly and green western Missouri southwest across the Great Plains of Kansas and Oklahoma to the Texas Panhandle where the terrain takes on a more brownish and rugged look. From the Panhandle the route takes you across New Mexico through Albuquerque then into eastern Arizona to Flagstaff and then south to Phoenix.

   So imagine using the same latitudes and longitudes on Earth, but this time put them on the surface of Mars. Assuming that something like this will become a reality in the future what types of terrain would you see along the way?
(Mars Geologic Map – source: USGS)

   
   
   

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3 Days – 3 Trails

   This past week I was in the Phoenix Arizona area enjoying some unusually cooler weather and the mountain and desert scenery. My goal was to hike as many days as possible until the weather got too hot – which was by Thursday. Morning temperatures were in the upper 60sF low 70sF but by around 9:00 am the temperature was in the upper 80sF heading for 100oF or higher.
   Nonetheless I got in two warm up morning hikes on Sunrise Mountain and Calderwood Butte. Both were typical of what I call City Mountains. They are largely igneous masses with considerable rocky rubble on most of the trails. Locally the trails are described as ‘ankle busters’ as it is easy to step incorrectly and injure yourself. What is neat about these ‘city mountains’ is that they are very easy to get to – many of which are parts of city park systems. Trails are fairly well marked although I use the AllTrails App to keep me on the right path.
   The 3rd day I spent several hours wandering around the Phoenix Mountain Preserve That morning I pushed it and completed 3 different but connected trails. Trail 1Trail 2Trail 3. This was an incredible area with trails every which way with many taking you away from the city sounds but nearly all required some uphill and downhill navigating. I encountered a few trails that going up or down were very steep but well worth the effort. Lots of interesting rock formations along the way.
   The geology of the area is a fantastic combination of igneous, metamorphic, and sedimentary rocks. Much of the level ground is outwash deposits from the surrounding mountains while the mountains are a mixture of igneous and metamorphic rocks. I saw what looked like either marble or chert, schist, and outcrops of slate among the types I recognized. There was a very obvious lean to many rock exposures and according to the geology of the area the rocks have a northeast strike.

   The video below shows some of the geology I encountered on these hikes.

   
   
   

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A Trail of 2 Geologies

   The Desert Is Calling!
   All trails lead west, or south, or anywhere but here. I am heading to Arizona for some latitude adjustment. Hiking, bouldering, and enjoying the desert/mountain Geology of Arizona as compared to the Geology of west central Missouri. So the next several posts will be from a desert perspective, looking Earthward as well as skyward.

   This map was made using Google Earth and a Geologic map made for each state. They are prepared as a KMZ file which may be loaded into Google Earth. Download the files by state from the USGS Geologic maps of US states web site.

   Yeah I know it is very hot there but, like a Pizza oven, it’s a dry heat!

   
   
   
   
   
   
   

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Mars – Saturn Heliocentric Conjunction – 2020

   Monday June 1st two of the outer planets, Mars and Saturn, will be more or less at the same heliocentric longitude of about 280o, and would be in what is called a heliocentric conjunction. Heliocentric (Sun-centered) coordinates uses an overhead view of the solar system with planet location given as degrees of heliocentric longitude. The heliocentric longitude is based on a view from the Sun and is given as the angle between a planet and the vernal equinox. The vernal equinox, 0o, is located within the constellation of Pisces the Fishes, and is the intersection between the ecliptic and the celestial equator.
   As the Earth revolves around the Sun it ‘gives’ the Sun its apparent motion eastward along the ecliptic. When the Sun crosses the celestial equator at this intersection it is moving north. At the crossing northern hemisphere winter becomes spring – the opposite seasonal change for the southern hemisphere.

   Despite having the same heliocentric longitude, when viewed from the surface of the Earth, the two show an east to west difference of about 2 hours of right ascension.

   
   
   

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Two More Go Retro!

   Retrograde motion is an apparent motion of any Sun-orbiting object as viewed from one object to another object further from the Sun than the one the viewing is made from. Since we are based on the Earth our views of the planets and other objects orbiting the Sun come from that perspective. As I posted the other day, outer planets. for example, orbit the Sun more slowly than the Earth. So there are times when, as the Earth passes an outer planet, the outer planet appears to slow down and then move backward, to the west. After a period of time the planet resumes its regular eastward, or prograde, motion.
   The retrograde motion of an outer planet is easy to understand and even visualize, however the two inner planets also undergo retrograde motion. Half of each their respective orbit is eastward, prograde, but when they reach the opposite side of the Sun their orbit carries the inner planet around the Sun through inferior conjunction (between the Earth and Sun) toward the west, retrograde, for the other half of the orbit.
   For the record each ‘side’ of the orbit is known as an elongation. So at western elongation the inner planet is on the west side of the Sun and rises before the Sun rises – a morning planet. Half an orbit later the inner planet is at eastern elongation and rises and sets after the Sun – an evening planet.
   Venus is currently very prominent as an evening planet over the western horizon at sunset. The planet Mercury has recently passed through superior conjunction is gradually moving into the evening skies. Mercury is moving in prograde motion while Venus is moving in retrograde motion.


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Saturn Goes Retro!

   All Sun orbiting objects further from the Sun than the Earth will have orbital speeds slower than the Earth’s orbital speed. From our perspective on Earth orbital directions are toward the east.
   There will come a time when the faster moving Earth will overtake a slower mover and pass by that object much like a car passes a slower moving car on the highway.
   During the time that Earth is passing by an outer object there is an appearance that the outer object slows down and then orbits in the reverse direction, toward the west.
   This is known as retrograde motion. After a few weeks to a few months, depending on the outer object, the apparent westward motion slows to a stop and then the outer object resumes its regular motion toward the east known as prograde motion.
   Such is the situation for outer ringed planet Saturn. It begins retrograde motion this month and will resume its regular eastward, prograde, motion during September.

   Take a short tour of Saturn and some of its moons in this video clip from the longer Orbits video. These were part of a live performance by the group Dark Matter.

   
   
   

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Earth Day – 2020

   It is the annual Earth Day this year on Wednesday April 22nd.
   What exactly is Earth Day?

“It is a day of political action and civic participation. People march, sign petitions, meet with their elected officials, plant trees, clean up their towns and roads. Corporations and governments use it to make pledges and announce sustainability measures. Faith leaders, including Pope Francis, connect Earth Day with protecting God’s greatest creations, humans, biodiversity and the planet that we all live on.”(https://www.earthday.org/earth-day-2020/)


   The theme for Earth Day 2020 is Climate Action
   
   Download the 2019 edition of NASA’s photo book, Earth (PDF).
 
Go to NASA’s Earth Day Toolkit web site for ideas and activities for parents and educators (which by the way, are one and the same. “Parents are Teachers!”


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Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.


Also Follow me and other great resources at Feedspot.