Over the next 10 days, from August 13th to the 23rd, the Moon will move eastward, as it always does, following the ecliptic and interacting with planets and stars near the ecliptic.
click on any graphic below to view each of the graphics full sized.
Monday evening August 13th the thin 2.5-day young waxing crescent Moon will be about 10o from the inner planet Venus, and about 8o from the Dwarf Planet Ceres. However at 8th magnitude Ceres will be not be naked-eye visible, but Venus at a -4.6 apparent magnitude will be hard to miss!
And spread out from west to east are the planets Jupiter, Saturn, and Mars.
Before sunrise on Saturday August 11th, Sunday August 12th, and Monday August 13th look toward the east and southeast for ‘shooting stars’, or meteors. The short-lived streaks of light are radiating outward from the area of the constellation Perseus the Hero. These are the annual Perseids – one of the best meteor showers each year. And these three days are centered more or less on the peak.
The Perseid Meteor Shower is named for the constellation from where the meteors radiate outward. This is the same for all meteor showers, and the ‘spot’ in the sky is known as the radiant. The Perseid radiant, as shown in the graphic, is within the Perseus constellation, and under ideal viewing conditions (dark and moonless skies) an average of about 60-80 meteors per hour could possibly be seen. This year without the interference of moonlight will increase the chances of seeing the meteors.
The peak for this year’s Perseids is Monday September 13th at 1 UT (8 pm CDT) however Perseus and the radiant rise at around 11 pm local time. A couple of hours later should be high enough over the horizon to become visible. I always look for a triangle made from using the Pleiades open star cluster, the bright star Capella in the constellation Auriga, and a not as bright star, Mirfak in Perseus. The radiant is up to the left from Mirfak as the graphic shows.
Best viewing times for seeing the Perseids are early morning a few hours before sunrise after Perseus has risen. This is an ideal time as the part of Earth you are viewing from is rotating toward the east, in the direction the Earth is revolving around the Sun. This means you will be seeing metaors ‘head-on’ as the enter the atmosphere.
Meteor showers result from the Earth’s orbital path intersecting areas of comet debris. Comets, as they orbit the Sun, leave behind pieces of their icy, dirty, selves. If these debris clouds happen to be along the Earth’s orbital path then the Earth will regularly pass through the comet debris cloud. As this happens the small comet pieces hit our outer atmosphere and vaporize from the friction generated heat. We then see these as the shooting stars that make up meteor showers.
Friday August 10th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Cancer the Crab and into the constellation of Leo the Lion. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.
Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
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.
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Friday August 3rd all of the planets, except for Mercury, and some of the Dwarf Planets will be over the horizon during the hours before sunrise and the hours before sunset. The dwarf planets Pluto (14.2), Haumea (17.2), Makemake (16.7), and Eris(18.5) with low apparent magnitudes are too distant to be visible other than with larger aperture telescopes. However Dwarf Planet Ceres, at 8th magnitude could be visible with smaller telescopes and certainly with long exposure time imaging.
Our Moon reaches apogee, (greatest distance from Earth), on Friday July 27nd. At that time the Moon will more or less be at a distance of 31.84 Earth diameters (406,223 km or 252,415. miles) from the Earth.
Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*
*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)
Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”
Friday July 27th the full Moon will be crossing 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.
Total Lunar Eclipse
When the Moon crosses the ecliptic, a node crossing, and the Moon is either at full or new phase there will be an eclipse. The length of the eclipse and whether or not it will be partial or total depends upon the timing. The closer the two events are to each other the greater the eclipse. This total lunar eclipse will be a long one at nearly 2 hours for totality. However the eclipse will not be visible from North America.
Get eclipse information from the Hermit Eclipse web site.
Watch the Lunar Eclipse live. Webcast hosted by the Bareket Observatory in Israel. Webcast starts at 18:30 UTC (1:30 pm CDT).
According to the pseudoscience of astrology, Sunday July 22nd the sun will be entering the constellation of Leo the Lion. In fact the Sun is still within the boundaries of the constellation Cancer the Crab, having just entered that region one day 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.
The Science of Astronomy has its roots in astrology with the origins of astrology beginning several millennia ago possibly by the Babylonians. Regardless of its origins the basis for at least Sun astrology, the popularized version printed in newspapers, is the position of the Sun relative to stars in the background. 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 slideshow below shows the sun’s position within Cancer on July 22nd 2016 AD, and then shifts to show the sun in Leo 4,000 years ago on 22 July 2016 BC. Precession has shifted the sun’s position one constellation to the west.