It’s the Time of the Season

A Martian Year

A Martian Year – at One Earth Month Intervals

   Today is the northern hemisphere spring equinox on the planet Mars as the planet transitions from winter to spring during its 684 Earth day orbit around the Sun. Seasons on Mars are marked by the planet’s heliocentric longitude coordinates using the position of Mars along its orbit around the Sun. Each seasonal start/ending point is 90 degrees apart, but because of its elliptical-shaped orbit each Martian season is of varying lengths. At the Martian spring equinox Mars is at 0 degrees longitude.
   I’m not exactly sure why this particular date is used but by international agreement astronomers have selected 11 April, 1955 as 0 degrees for year 1 of this Martian calendar. What this means is that today, 31 July Earth time, is the start of a ‘new year’, the first day of spring for year 32 using the aforementioned calendar system.

Year 32
0 degrees — Spring Equinox — Jul 31 2013
90 degrees — Summer solstice — Feb 15 2014
180 degrees — Fall Equinox — Aug 17 2014
270 degrees — Winter Solstice — Jan 11 2015
Year 33
0 degrees — Spring Equinox — Jun 18 2015

Learn a little (or a lot) more about Mars at the NASA/JPL Mars Curiosity mission web site.

Here is approximately 3 minutes worth of Mars from the Orbit performance.

Error
This video doesn’t exist

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Mercury Goes to Extremes

   mercury-aniToday the innermost planet Mercury reaches a point along its orbit around the Sun where it is more or less at a right angle from the Earth and the Sun, as the banner graphic at the top of the page shows. As viewed from above Mercury is to the right from the Sun, while from the backyard view on the Earth’s surface Mercury is also to the right from the Sun, or on its west side. This puts Mercury in the morning skies rising before the Sun rises and leading the Sun across the sky from east to west as the Earth rotates from west to east.

Earth, Inner Planets, and the Ecliptic

Earth, Inner Planets, and the Ecliptic

   From our backyard perspective we view the planets at more or less the same level because the 8 planets orbit the Sun on or close to the plane of the ecliptic, the Earth’s orbit extended outward from the Sun. So from this perspective the two inner planets appear to move back and forth, left to right to left, as they orbit the Sun. Today Mercury is at the ‘turning point’ on the right side of the Sun, which places Mercury at its greatest western elongation, or at its maximum angular separation from the Sun as seen from Earth. Today Mercury is approximately 20 degrees from the Sun. Due to its closeness to the Sun Mercury never gets more than around 30 or so degrees from the Sun which means that Mercury never rises or sets more than about 2 hours from the Sun. (The Earth rotates approximately 15 degrees every hour)

Click here to learn a little (or a lot) about the innermost planet Mercury from two MESSENGER web sites.

30 July - 5:30 am CDT

30 July – 5:30 am CDT

   While out observing Mercury look a little higher to the right for the planets Mars and Jupiter, plus some of the stars of the northern hemisphere winter season. While these two outer planets are also to the west from the Sun they do not have an elongation position as outer planets orbit the Sun beyond the Earth’s orbit rather than between the Earth and the Sun. Outer planets do reach a 90 degree angle relative to the Earth and the Sun but it is known as either east or west quadrature.

30 seconds worth of Mercury from the Orbit performance.

Error
This video doesn’t exist

   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Saturn at East Quadrature

Click on this image for full size

Click on this image for full size

   Today the position of the planet Saturn with respect to the Earth and the Sun places this ringed planet at what is called eastern quadrature. Saturn is at a 90 degree angle from us as this graphic shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Saturn follows the Sun across the sky from east to west as the Earth is rotating, meaning that Saturn rises after the Sun and sets after the Sun.
   Where is Saturn now? Click here to see a graphic showing Saturn and some of the brighter stars over the southwest horizon at 10 pm CDT.

Learn a little (or a lot) more about Saturn by visiting the Cassini at Saturn mission web site.
Click here to go to the Cassini Mission web site.
Click here to go to the Cassini Mission Flyby web page to see when the next Saturn satellite flyby will be.

   This is a short 5 minute video I made as part of a live musical performance called “Orbit” that I was part of in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Saturn and some of its moons as viewed from the Cassini spacecraft that month.

Error
This video doesn’t exist

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Preview August Issue of Qué tal

voki   As the subject line states, the August preview issue of Qué tal in the Current Skies is now online and available at this temporary web address: http://currentsky.com/2013/aug13/index.html
   It will be at its regular web address in a few days.

   Thank you for your support and encouragement.
   Clear Skies…
   Bob Riddle

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Sun Not In Leo Today

   On this date, according to the pseudoscience of astrology, the sun is entering the constellation of Leo the Lion. In fact, as the banner graphic at the top of the page shows, the Sun is still within the boundaries of the constellation Cancer the Crab, having just entered that region two days ago.
   The difference between the two locations of the Sun, the correct astronomical vs. the incorrect astrological, is due to the effects of precession, or more specifically, the precession of the Earth’s axis. The Earth wobbles on its axis like a spinning top does as the top slows down. So, in approximately 26,000 years the Earth will have spun, or wobbled one time. This is a repetitive cycle and over the course of one precession cycle the poles of the Earth trace out a circle against the background stars over their respective pole. any star on or nearest to this precession circle is the pole star. Currently the north pole of the Earth points toward Polaris and within this century, due to precession, will point the closest it will be, and then over time the Earth’s north pole will shift away.
   Another effect of precession has been to cause the celestial grid system to shift moving the original signs of the zodiac by at least one constellation to the west. In other words the Sun is more to the east which in effect means that whatever your zodiacal sign may be according to astrology, you are really the constellation to the west, or before it according to Astronomy.
   Click here to read a little more about precession from a previous blog.
   It is written elsewhere that astrology came into practice somewhere around 3000 BC as observational astronomy evolved from oral to written and graphic formats. So the basis for at least Sun astrology is the position of the Sun relative to stars in the background some 3,000 years ago. However we now know that due to the effects of precession the Sun’s position is no longer as it was during the beginnings of astrology. The two-part slideshow below shows the sun’s position today within Cancer, 22 July 2013 AD, and then shifts to show the sun in Leo 3,000 years ago on 22 July 1013 BC. Precession has shifted the sun’s position one constellation to the west.

   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Mars – Jupiter Conjunction

22 July - 5:30 am CDT

22 July – 5:30 am CDT

   Tomorrow morning, 22 July, the planets Mars and Jupiter will be less than 1 degree apart. Look toward the east-northeast horizon for the bright Jupiter and the dimmer Mars nearby. The banner graphic at the top of the page as well as this graphic are set for 5:30 am CDT. By that time the sky is fairly bright but it may still be dark enough to make out the stars of the open star cluster M-35, just above the two planets. All three objects will easily fit within the field of view of 7×50 binoculars.

   
   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Venus-Regulus Conjunction

Venus Meets Regulus

Click on image for full size

   This evening and tomorrow evening the inner planet Venus will be about 1 degree from the bright star Regulus in Leo the Lion. Venus is currently moving eastward along its orbital path out away from the Sun. This month and next month Venus will be the ‘bright’ object over the western horizon at sunset. However due to the low angle of the ecliptic Venus will not be very high above the western horizon as viewed from the northern hemisphere. Click here to see a graphic showing the ecliptic and Venus’s orbital path.
venus   As seen from a backyard perspective with a telescope Venus appears relatively small and in the gibbous phase.
   Click here for VR view of the sky – requires the Quicktime Player if the video file is downloaded.

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Sun Enters Cancer

The Sun 'is in' Cancer

The Sun ‘is in’ Cancer

   At 1 pm CDT today, 20 July, the Sun in its apparent eastward motion crosses the boundary between the zodiacal constellations of the Gemini Twins and Cancer the Crab.
   The Sun is said to be ‘in’ Cancer – a reference to the Sun being somewhere within the boundaries, or borders of a constellation.
   This also marks the Astronomical or true position of the Sun’s position along the ecliptic relative to the thirteen constellations of the Astronomical zodiac in the background.

   
   
   Click here to go to the Qué tal in the Current Skies web site for more observing information.

In the Scorpion’s Grip – Again

The Many Views of scorpius

The Many Views of Scorpius

   This evening, 18 July, the Moon is once again the claws of Scorpius the Scorpion. However unlike last month, the month before that one, or even the next months coming up the phase, age, and exact location of the Moon are different. This evening the waxing gibbous Moon will be 10.6 days old while in the scorpion’s grasp.
So where will the Moon be next month at about this phase? On 14 August the waxing gibbous Moon will be 7.96 days old and will be to the west of scorpion’s pincers. On 15 August the 9.08 day old Moon will be just east of the Scorpion’s pincers.
   The animated graphic to the right is set for 10 pm CDT, and cycles through an image of the scorpion, a star pattern by H.A. Rey; a zodiacal pattern; just the stars; and then just the stars with the heart of the Scorpion, the reddish star Antares labeled.
(H.A. Rey wrote the Curious George books, and also a book about constellations in which he drew the star patterns differently than the classical patterns – The Stars: A New Way to Know Them.)
Click
here to go to the H.A. Rey web site.
Click here to read what I wrote about the Moon phases and monthly position shift and how it happens in a blog from about ‘this time’ last month.

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

Martian Flight-Seeing

   The ESA, European Space Agency, recently released a short 5 minute video of a fly over of the Hebes Chasma, a canyon lying along the Martian equator near the Mariner Valley. This canyon is around 8000 m deep and is thought to have had water flowing through it in the past.
dexter   The video offers a fascinating look at the Martian surface features however there is no narration nor music. So… I added a favorite Mars themed song by Jazz artist Dexter Wansel to the video. The song, “Life on Mars” is on one of the albums in my record collection. The song was part of the audience walk-in music I used to play years ago when I worked in a Planetarium in Peoria Illinois. The walk-in music preceded the showing of a Planetarium show about Mars that was narrated by Carl Sagan. While the show was a good one it had what I thought was the most annoying musical soundtrack I had ever had to listen to.
   Watch the ESA produced video below. Also watch one of the early Mars fly over videos produced by NASA. This one takes you around the Mariner Valley system. That video was produced in the late 1980s and the difference in video technology and imaging capabilities is very obvious. And the soundtrack is rather familiar!

Click here to go to the ESA web site.
Click here to view the original video at the ESA web site.
Click here to go to the NASA Mars Reconnaissance Orbiter web site.

   The banner graphic at the top of the page is from a colored topographic map of Mars. Click here to download the map.

Click here to read my review about ‘The Martian’, a fictional account of a survivor on Mars.

Error
This video doesn’t exist
Error
This video doesn’t exist

   Click here to go to the Qué tal in the Current Skies web site for more observing information.