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.

NSTA @ Nashville


   I’m in Nashville Tennessee for the next several days at the NSTA national conference. Planets and stars will still be in the skies but not as easy to see from downtown Nashville as it is where I live. On the morning of April 1st the waning waning crescent Moon will be within a few degrees from Dwarf Planet Pluto. Too dim to be seen without a large telescope it is, nonetheless, a neat idea that when you look toward the Moon you are also looking in the direction of Pluto. It’s out there!
   And here is a sequence of graphics showing the pre-sunrise morning sky at 5:30 am EDT for each day during the conference, and one night view on April 1st showing Jupiter. Both Pluto and the Moon are located just above and to the left from the handle of the teapot asterism for Sagittarius the Archer.

   
   
   

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.

ISS This Morning

Screenshot_2016-03-25-06-42-20   This morning, despite the cold temperature there were exceptionally clear skies and so I had a great view of the International Space Station as it passed nearly directly overhead. It always amazes me how quickly the space station moves. In 10 minutes it traveled from over the North Pacific Ocean near the Aleutian Islands to my location in Missouri. Then about 40 minutes after passing over Missouri the ISS is south of Africa.
   As the ISS approached my location it rose up from the northwest horizon passing the bowl of the Big Dipper. Then as it set toward the southeast the ISS went right down one side of the Summer Triangle asterism passing the stars Vega in Lyra the Harp and Altair in Aquila the Eagle.
   The screen captures are from an App, ISS Onlive, on my cellphone. This App (Android and Apple) shows the current orbit of the ISS and also has options to show a look-down view of the Earth as the ISS orbits.
   The two pictures are a set of stacked pictures all taken with the same camera settings: 18mm; ISO 1600; F4.5; 4 sec.

   
   
   
   

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.

A Tale of Two Skies

distance   I had an interesting Skype chat last evening with a young man from Argentina who at the time is living in Quito Ecuador. We talked about many things celestial as well as geographical – both of which are passions we share. Pablo is from the city of Esquel in the Chubut Province of Argentina. Pictures of the area remind me of where my wife and I once lived in the mountains of west Texas, the Big Bend Country.
   However what has always intrigued me is the appearance of the sky from a different latitude. I live at approximately 39o North, and Esquel is approximately 43o South. For general observing purposes longitude is less important as it is simply the difference in the time when something becomes visible above the local horizon. Our respective Longitudes are different by about 20o while the time zone difference is 3 hours. My time zone, CST, is UTC-6 or 6 hours after the time in Greenwich England. Esquel and Argentina are UTC-3 or 3 hours after the time in Greenwich England.
   Below are two graphics I made to show the view an hour before sunrise local time. Both views face toward the Earth’s equator, the direction to typically look for the other planets and our Moon. However from the Northern Hemisphere one looks toward the southern horizon while from the Southern Hemisphere one looks toward the north for the planets and the Moon. At mid-day the Sun is at its highest above the horizon and is mid-way across the local sky between rising and setting. In the Northern Hemisphere the Sun at mid-day is above the southern horizon, and it is over the northern horizon from the Southern Hemisphere.

    An interesting way to compare these two cities, or those of your choice, is from viewing information generated at the Heavens Above web site.
    Here is a link to the Heavens Above web site set for Lee’s Summit, Missouri, USA.
    Here is a link to the Heavens Above web site set for Esquel, Chubut, Argentina.
   
   
   
   

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.

March 2015 Equinox and Solar Eclipse

   Friday March 20th is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’ (starts). For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At mid-day on the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

seasons-ani  Northern hemisphere spring officially (well at least astronomically) begins at 22:45 UT (4:45 pm CST) on the 20th when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. At this location the Sun is within the constellation of Pisces the Fishes and not just entering Aries the Ram as the pseudoscience of astrology would have you believe.

    To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   The time of this equinox is about 13 hours after a new Moon phase and a solar eclipse. This picture shows the shadow of the Moon cast on the Earth during a solar eclipse as seen from the International Space Station.

   Click here to see the online world sunlight map used to make the day/night graphic at the top of the page.

sun-earth   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

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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.

An EarthKam Mission

iss_flyover-ani   This coming week, the last one in January, is going to help make this month a more memorable month than I had previously thought.
How so?
Firstly January marks my 200th monthly column of Scope on the Skies for Science Scope Magazine, the NSTA‘s Professional Journal for Middle School Science Teachers. In that column I wrote about Earth viewing missions.”A New Year, A New Earth View”. take-pics   Secondly, and very coincidentally, earlier this month an opportunity came up to apply to take part in the next scheduled Sally Ride EarthKam Mission. I was accepted and so this week will be for requesting images on the orbits between Sunday and Friday.
“Doing this alone?” You ask.
I have teamed up with two Science Teachers at Summit Lakes Middle School here in Lee’s Summit Missouri, and starting Monday morning students will begin making their requests. Also my college Astronomy class students will be requesting images as part of a lab lesson on tools Astronomers and Earth Science (among others) use.
cover
Making requests is a simple 10 or so step process beginning with logging in to the web site. However the Teacher first needs to register at the mission website, and then register for the next mission. The teacher will receive a list of codewords a few days ahead of the actual mission dates. Each codeword may only be used once; one codeword = one picture request. I’ve prepared a guidebook of sorts using screen captures that steps through the process of logging in and making a request. A more detailed and useful guidebook is the one prepared by the Sally Ride EarthKam Mission folks. Some time ago I wrote a short blog about the EarthKam mission.
orbits-ani

Our week looks promising for getting pictures of the southern hemisphere according to the mission orbit plotter. That is weather permitting. By clicking on the desired orbit group the map will then display the paths for that group. Remember that red lines show where it will be daylight and only when pictures could be taken.
zoom-ani

Using Google Earth means that you are able to zoom in to better place your marker for a picture. There are limits to getting a ‘good’ picture, one taken from as directly overhead as possible. Specifically it is the distance from the ISS orbit path. The further away from the orbit path the lower the ISS will be relative to the horizon.

I’ll share the pictures sometime next week after we get them.

[centup]
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.

Tweets From ISS

iss-pic   If you have followed my postings you know that I am an avid fan of watching for the International Space Station passages over my part of the world. I especially enjoy capturing the ISS as it travels past celestial objects like the Moon.
iss-crop   In an interesting twist it is possible to take advantage of the ‘bird’s-eye’ view from the ISS and see what the ISS astronauts see as they orbit the Earth. Listed below are some of the web sites with pictures taken by ISS astronauts, however I wanted to call attention to this web site – ISS EXPS 40 & 41. This web site has a map of the world that links tweets from the astronauts to accompany the pictures they took of the Earth’s surface.
   Additionally the web site shows the position of the ISS updated every minute so you can track its current flight and position as you browse the pictures.
Click here to go to the ISS Exps 40 & 41 website.

Some ISS sighting web sites:

NASA Space Station Live
ISS Sightings
Heavens Above

Pictures from Astronauts on the ISS:

Gateway to Astronaut Photography of Earth
ISS Astronaut Pictures of Earth

   
   
   
[centup]
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.