February Moon at Descending Node and a Solar Eclipse

26feb-descending-node
   Sunday February 26th the new 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. The time for new Moon phase 14:59 UT while the time for the node crossing is 8 hours earlier at 6:40 UT. Given the close times for the two events means that there will be a solar eclipse. However the Moon, because of its elliptical shaped orbit, will be at a further distance from the Earth such that it will appear smaller in diameter than the Sun appears. This means that at mid-eclipse, or totality, the Moon will not completely cover the Sun, instead there will be a ring of sunlight around the Moon. The ring of sunlight is called the annulus and so this is an annular solar eclipse. The eclipse will be visible from parts of southern Argentina and western central Africa.
annular-eclipse-ani   On my birthday in 1994 I was ‘honored’ to not only have an annular solar eclipse on that day but the eclipse path, the path of annularity, crossed right over where I live southeast of Kansas City Missouri. This animation is of the May 10th annular solar eclipse.

   
   
   

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

Sun Enters Scorpius-2016

   Tuesday November 22nd the Sun, in its apparent eastward motion along the ecliptic, moves out of the constellation Libra the Scales and into the constellation of Scorpius the Scorpion. 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.

2016 September Equinox

   On Thursday September 22nd at 14:21 UT, (9:21 am CDT) the Sun will have reached the astronomical coordinates of 0 degrees declination and 12 hours of right ascension, or RA. This places the Sun within the boundaries of the constellation Virgo the Maiden, or as some would say, “the Sun is in Virgo.” This is the actual position of the Astronomical Sun as opposed to the pseudoscience of astrology which has the astrological Sun entering the constellation of Libra the Scales.
   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.
   Declination is the astronomical equivalent to latitude measuring from 0 degrees at the equator to 90 degrees at either pole. Right ascension, or RA, is like longitude except that there is only east RA. The globe is divided into 24 sections, and like meridians of longitude, these hour circles are 15 degrees wide at the celestial equator and taper to a ‘point’ at the north and south pole respectively. In RA the ‘hour’ circles are counted from 0 hours to 23 hours. The 0 hour circle is at the intersection of the ecliptic and the celestial equator in the constellation of Pisces the Fishes.
   In a class lesson about seasons today would be one of the two days during the year when the Sun would be described as being over the Earth’s equator. If you were at the Earth’s equator the Sun would have an altitude of 90 degrees, or straight up in your sky at your local time for midday. At that moment there would not be a shadow. However at any other latitude, north or south at midday, the Sun would be at an angle less than 90 degrees and there would be a midday shadow. (Midday is the local time when the Sun is halfway between local rising time and local setting time. At any midday the Sun is at its maximum altitude above the southern horizon in the northern hemisphere, or is at its maximum altitude above the northern horizon in the southern hemisphere.)
   What is often noted about an equinox day is the reminder that equinox means equal night as a reference to there being equal amounts of daylight, and night. Also on an equinox day the Sun would rise due east and set due west for virtually everywhere on the globe. The times for sunrise and sunset would be approximately 12 hours apart, and the rising time would be around 6 am local time, and the setting time would be around 6 pm local time.

Hola Moon doh

Hola ‘Moo’ndo! Think Globally.

   So why “September Equinox” instead of using the more familiar “Fall Equinox”. Primarily because the southern hemisphere is also changing seasons on this day however for the southern hemisphere this is the start of their spring season. Despite the opposite seasons it is somewhat of a northern hemisphere bias that traditionally we would call this day the “Autumnal or Fall Equinox”, and in March we would say the “Spring” or “Vernal Equinox”. I favor the use of the name of the month so that regardless of which hemisphere it is just simply the March equinox or the September equinox, and by extension we would also have the June solstice and the December solstice..
   
   This short video shows students at Colegio Menor San Francisco de Quito, a school in Quito Ecuador, measuring the altitude of the sun hourly on the day of the 2004 September Equinox. They were taking part in Project SunShIP, Sun Shadow Investigation Project. There are also some pictures showing a local midday shadow from other participating schools in the United States and U.K.

   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Seeing is Believing


   So I told my evening class that there was a sunspot so large it could be seen with the naked eye. The Sun was still more than an hour from setting when I set up my camera on the steps behind the Science building. As my students came outside I handed them each a pair of ‘eclipse glasses’, and they were all able to confirm that they were able to see the sunspot.

Some students from my evening Astronomy class

Some students from my evening Astronomy class

   I will repeat this tomorrow morning with my day class students. Stay tuned!

Some of the students in my morning astronomy class.

Some of the students in my morning astronomy class.

   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

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

M is for Monster Sunspot


   Today there is a very large sunspot that has been described as large enough to see with the naked eye at sunset or sunrise. I would not recommend looking at the Sun unless you have proper viewing equipment.
   This picture is one of a couple of quick shots of the Sun from earlier today. The large sunspot is rather distinct. The camera particulars are on the picture. I use a screw-in 58mm solar filter on my DSLR camera, a Canon Rebel T3i. The filter shows the Sun in visible light and comes from Thousand Oaks Optical and is reasonably priced. If you have never imaged the Sun before this is one path in that direction.

   Reminder: On a clear day you can see 92,955,807.26 miles (149,597,870.69 km)

   
   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Sun Enters Aquarius

feb-view from earth   Monday 16 February at 20 UT (2 pm CST), the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Capricornus the Sea Goat and into the constellation of Aquarius the Water Bearer. 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. Which will be Wednesday 18 February when the sun is not in Pisces according to astrology.

   
   
   
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Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Along the Ecliptic

   In the posting yesterday I described the shape, or eccentricity, or the Earth’s orbit as not being a factor in how we have seasons. As we all should have learned it is the tilt of the Earth’s rotational axis relative to the plane of the ecliptic. This tilt is approximately 23.5o and this combined with revolution around the Sun is as they say ‘the reasons for seasons.’
    But this is not the point of this posting, but rather it is the plane of the ecliptic and where planets, dwarf planets, and our Moon orbit relative to the plane of the ecliptic. This relationship is known as inclination and it is the angle, in degrees, above the plane of the ecliptic. What this means is that the Earth’s orbit the bright green line, which is in reality the ecliptic, is the reference plane from which the other Sun orbiting objects respective orbit is tilted from. If you follow this explanation, and perhaps have read or noticed that each month I have posted when the Moon reaches its ascending or descending node. This ascending and descending node also applies to the other planets and dwarf planets as well because the planets and dwarf planets, like our Moon, have orbital paths tilted away from the plane of the ecliptic as this graphic shows. The table below shows the inclination for the planets and one dwarf planet.

   What got me started on this was in part from what I wrote yesterday but also yesterday evening as I was attempting to get some pictures of the rising full Moon through some trees. This was despite the air temperature being near 0° F! Nonetheless as I was looking around enjoying the first really clear sky evening in a several weeks I couldn’t help but notice how Mercury, Venus and Mars were lined up from west to east along where I visualized in my mind the location of the ecliptic. Then using my ‘go to’ Astronomy simulator I set up a slideshow with the ecliptic, planets, a few dwarf planets, and our Moon displayed and set to 1-hour intervals starting with sunrise 7:30 am CST, my local time. You can see how the planets are very close to the ecliptic compared with the dwarf planets. The Moon is sometimes below, sometimes above, and sometimes right on the ecliptic – which if timed right gives us an eclipse.

Inclinations of 8 Planets and 1 Dwarf Planet
Name	Inclination
Mercury	7.01°
Venus	3.39°
Earth	0°	
Mars	1.85°	
Jupiter	1.31°
Saturn	2.49°
Uranus	0.77°
Neptune	1.77°
Pluto	17.15°

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Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.