Tag Archives: astronomy

Calendar: 2. Universal Time Coordinated (UTC) and Astronomical Dates

Iwaya-Iwakage of Kanayama Megaliths

UTC

UTC stands for Universal Time Coordinated, or Coordinated Universal Time. It is the standard used for standard time zones around the globe. It is also the standard used for astronomical events.

“Coordinated Universal Time or UTC is a standard, not a time zone. In other words, it is the base point for all other time zones in the world. They [other time zones] are determined by their difference to UTC. UTC [itself] is represented as UTC +0.

“Coordinated Universal Time is a 24-hour time standard that is used to synchronize world clocks. In order to keep Coordinated Universal Time as accurate as possible, two other time standards are used: International Atomic Time or TAI, and Universal Time also known as Solar Time.” https://www.worldtimeserver.com/time-zones/utc/. See also https://www.timeanddate.com/time/aboututc.html.

Translate UTC to your time zone

This is explained at EarthSky here. You must convert UTC to your own…

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Calendar: 1. Observing the Sun in the Sky

Iwaya-Iwakage of Kanayama Megaliths

Figure 1. A sunwatcher looking at the path of sun in the sky over the course of a year. Art by Shiho Tokuda (by permission).

An Ancient Global Solar Calendar

The Kanayama Megaliths of Central Japan were built around 5000 years ago during the Jomon Period. They are still in full operation, as we have been reporting on this site, as a super-accurate solar calendar. The Kanayama Solar calendar is aglobal calendar.This series of posts will show this. We begin with some basic astronomical facts related to the passage of the sun in the sky, as seen from earth.

Observing the Sun in the Sky

Indigenous people around the world have been watching the sun in the sky to know the seasons. Even if they knew that the earth orbits the sun, nevertheless, in terms of human living it is as if the sun goes around the earth…

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See planets this month of August 2021

This image is from EarthSky, and here is an excerpt:

From most of Earth in early August, Saturn and Jupiter ascend in the eastern half of your sky by mid-evening (midway between your local sundown and midnight). Both are bright and noticeable! This chart is via Stellarium; try it to view the orientation of the planets from your specific location on the globe. In a dark sky, notice the famous Teapot in Sagittarius, and the graceful J shape of Scorpius the Scorpion, near Saturn and Jupiter (to the right of them, on this chart).

Click the Stellarium link and view the interactive night sky. Enjoy!

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Happy New Year 2018! Happy Perihelion!

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Earth and sun via ISS Expedition 13/ NASA

Greetings of the New Year to All!

We on Earth have only a few weeks ago observed our December Solstice, when days are shortest in the Northern Hemisphere and longest in the Southern. It was the time of the New Year for indigenous people around the world. Now, we are celebrating the conventional New Year for our times at the beginning of the Western calendar in January.

Did you know that, on January 2 and 3, Earth will be closest to the Sun in our orbit around the Sun? This is always true around this time in our history. EarthSky writes:

On January 3, 2018, Earth at its closest point swings to within 91,401,983 miles (147,097,233 km) of the sun. That’s in contrast to six months from now, when the Earth reaches aphelion – its most distant point – on July 6, 2018. Then we’ll be 94,507,803 miles (152,095,566 km) from the sun.

In other words, Earth is about 3 million miles (5 million km) closer to the sun in early January than it is in early July. That’s always the case. Earth is closest to the sun every year in early January, when it’s winter for the Northern Hemisphere.

Do you wonder if the solstice and the perihelion, the closest approach of Earth to Sun, are related? This is not always true, because the dates change in the course of centuries. In fact, in the year 1246, both occurred on the same day. We are living in very interesting times…

Here’s the explanation from EarthSky.

Earth comes closest to the sun on January 3, 2018 at around 5:35 UTC; translate to your time zone. This event is called Earth’s perihelion. Meanwhile, the December solstice took place on December 21, 2017. At perihelion in January, Earth swings to within about 91 million miles (147 million km) of the sun. That’s in contrast to six months from now, when we’ll be about 94 million miles (152 million km) from the sun. At the December solstice, Earth’s Southern Hemisphere is tilted most toward the sun; it’s the height of summer in that hemisphere. Are the December solstice and January perihelion related? No. It’s just a coincidence that they come so close together.

The date of Earth’s perihelion drifts as the centuries pass. These two astronomical events are separated by about two weeks for us. But they were closer a few centuries ago – and in fact happened at the same time in 1246 AD.

As the centuries continue to pass, these events will drift even farther apart. On the average, one revolution of the Earth relative to perihelion is about 25 minutes longer than one revolution relative to the December solstice. Perihelion advances one full calendar date every 60 or so years.

December Solstice Greetings

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Megalith for viewing winter solstice sunrise (photo by S. Tokuda)

 

One Earth, One Sun, One People

In ancient cultures, winter solstice day was the beginning of the new year. On this shortest day of the year, people knew that the next day would start to be slightly longer, and spring would be coming. Winter solstice is a symbol of rebirth and regeneration.

December 21 and 22 mark the days of the solstice which we call the winter solstice in the Northern Hemisphere, summer solstice in the Southern Hemisphere.

Iwakage has posted an article entitled, Winter Solstice 2017. It gives some of the dates and times in various time zones around the world. At the instant of time that is astronomical solstice, it is already early Friday morning of the 22nd in Japan, where Iwakage is located. One of the “earliest” times is in Hawaii when the solstice occurs at 6:28 a.m. on the 21st.

To our readers around the world, thank you for visiting us:

U.S., Japan, France, Italy, U.K., Australia, Canada, Brazil, Germany, Morocco, Russia, Netherlands, Spain, India, Philippines, Hungary, Singapore, Malaysia, Hong Kong, Indonesia, Ireland, Belgium, Mexico, Switzerland, Estonia, Chile, Thailand, New Zealand, Serbia, Bulgaria, Portugal, Austria, S. Korea, Ukraine, Argentina, Finland, Romania, Poland, Taiwan, Switzerland, Slovenia, S. Africa, Israel, Greece, E.U., Norway, Cape Verde, Czech Republic, Luxembourg, Peru, Denmark, United Arab Emirates, Colombia, Turkey, China, Iceland, Belarus, Croatia, Pakistan, Latvia, Bahrain, Saudi Arabia, Bangladesh, Lithuania, Puerto Rico, Slovakia, Venezuela, Panama, and eighty other countries.

Seeing the names of these 150 countries truly impresses upon us that we are all One People living on this Earth under our Sun. Solstices, equinoxes, and all the days of the year come to all of us. Although the times on our clocks may differ, these astronomical times are the exact same moment for all of us.

Okunomichi wishes every one of you a Happy New Year!

 

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Lahaina Noon Update:  Kau ka la i ka lolo

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Our earlier post on Lahaiana Noon , https://okunomichi.wordpress.com/2016/05/07/1711/has been visited by many. This post is about Kau ka la ia ka lolo, the traditional term for the passage kau of the sun at the zenith over one’s head.

At the Windward Community College in Kaneohe, Hawaii, is a Polynesian voyaging display on permanent view. It is highly recommended for those interested in how the Polynesian people journeyed over vast distances with great navigational skill. You can view a scale model of the  Hōkūleʻa voyaging canoe and an introduction to Hawaiian astronomy. We thank Professor Joseph Ciotti for preparation of the exhibit and explaining it to us. Dr. Ciotti remarked that it was the eminent Hawaiian historian, Rubellite Kawena Johnson who provided him with the proper term for this celestial event. 

We show a photo we took of the Kau ka la ia ka lolo exhibit. The text reads as follows:

Twice a year the noontime sun passes directly overhead. Kau ka la ia ka lolo was believed to be a time of great mana. At this moment a person’s shadow (aka) disappeared and was thought to enter his sacred head. The two dates for these solar zenith passages are marked on the map for different places on O’ahu.

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Egyptian Calendar Basics

The year of the astronomical Egyptian Calendar began on the summer solstice, SS, when the Nile flooded. This system is thought to have begun ~ 3000 BCE (2750 BCE). The solar calendar was not modified by leap years so that it gradually shifted away from the New Year Day being on the SS day. The period of this cycle is ~1500 of our years, when New Year once again began on SS. It is highly likely that the Egyptians, being fully aware of this drift, deliberately used it for a higher order calendar cycle. For example, by the time of Khufu of the Fourth Dynasty, the New Year Day was already between the SS and the spring equinox.

The estimated date of the  start of the calendar is based on the heliacal rising of Sirius on the SS. In other words, when both the Sun and Sirius rose in the eastern sky, and which signaled the beginning of the flood season. After a drift of about 1500 years, on about 1500 BCE (1250 BCE), the New Year would again fall on the SS. This did happen at the time of Ramses II.

Sidereal Calendar

Although the Egyptian religion venerated the Sun, the astronomers were keenly interested in the rising of stars, thus they had a sidereal calendar. In particular, they watched for the heliacal rising of the Orion constellation which symbolized Osiris, and for the star Sirius (Sothis in Greek) which represented Osiris’ consort Isis. The star knowledge of Egypt may have come from Babylonia. In any case, the sidereal calendar was based on the heliacal rising of Sirius/Sothis.

The ritual calendar of the astronomer-priests was thus the Sothic or Sidereal year of 366 risings of Sirius. On the other hand, the agricultural solar calendar of the farmers was attuned to the summer solstice when the Nile flooded its banks and planting could begin.

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Note:  The above chart is from Belmonte,  http://www.iac.es/proyecto/arqueoastronomia/pages/project-overview/highlights-hitos/egyptian-calendar.php

Labels in red have been added to indicate the times of Khufu (IV Dynasty), V Dynasty, Middle Kingdom, and Ramses II.

Egypt Code by Robert Bauval, 2010, provides further information about the Egyptian calendar, in particular the sidereal calendar.

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Hi no Michi, Path of Sun

A fuller report on Hi no Michi is presented by Iwaya Rockbat at:   https://iwakage.wordpress.com/2016/06/16/hi-no-michi-path-of-sun/

Hi no michi ya

aoi katamuku

satsuki ame

— Basho

Hi no michi, the path of the sun in the sky.

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Photo credit:  http://studiesofplantsandwildlife.blogspot.com/

Hi no Michi alignment map.  We have recently encountered the map of important shrines throughout Japan connected by the Hi no Michi. Hi-no-michi mapSee: https://okunomichi.wordpress.com/2016/06/02/awa-mystery/.

Hi no Michi at Kanayama Megaliths.   The solar calendar of Kanayama Megaliths is based on the path of the sun during the year. The sun travels in a certain zone in the sky. Its northern limit is during the summer solstice day, while its southernmost is at winter solstice. At equinox, the sun travels the central path in the sky.

Sunpath2

http://www-istp.gsfc.nasa.gov/stargaze/Secliptc.htm

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Dashed Spotlight and Lahaina Noon as Summer Solstice Indicators

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Iwaya Rockbat published the May 21 dashed spotlight report for 2016, https://iwakage.wordpress.com/2016/05/26/dashed-spotlight-of-21-may-2016/

The appearance of this spotlight in the grotto of Senkoko-Ishi heralds the coming of summer solstice 31 days hence, in other words June 21, 2016 at Kanayama Megaliths. And 31 days after the solstice, July 23, the dashed spotlight will make its last appearance of the year. There are 62 days between the two dates, and the solstice is in the middle. Remember, between spring and autumn, the sun daily moves northward until the solstice and then moves southward, retracing is path. This dashed phenomenon only lasts for a few days each time.

Okunomichi has published two posts on Lahaina Noon, (1)2016-05-25 12.27 stopsignhttps://okunomichi.wordpress.com/2016/05/07/1711/  and (2) https://okunomichi.wordpress.com/2016/05/.

What is Lahaina Noon? It is the popular term used in the Hawaiian Islands for the two days per summer when the noontime sun is directly overhead any given spot in the Islands (Okunomichi link 1). On those two days, the zenith sun casts no shadow of thin vertical objects such as poles and stop signs (Okunomichi link 2). Those two dates in 2016 for four Hawaii cities are listed in the first of the two posts. For Honolulu, Oahu, the dates are May 26 and July 15; for Hilo, Hawaii, they are May 18 and July 24. On the Tropic of Cancer, there is only the one date of the summer solstice itself, June 20.

It occurred to Iwaya Rockbat that stop signs such as the one shown by Okunomichi can be used as indicators of summer solstice date, just as the dashed spotlight does. Using the dates given for Honolulu, May 26 and July 15, we counted the number of days between them and found there were 50 days. The middle date will occur 25 days after May 26. It will be June 20. It is exactly right for Honolulu!

For Hilo, the two dates are May 18 and July 24. The designated summer solstice date is June 20. Again, this is perfectly right!

So, what prevents us from using signposts in Hawaii to determine by observation the date of the summer solstice? The big issue is the accuracy of observation. The day before the photo was taken, Okunomichi had taken a similar photo of the same signpost. The shadow was close to non-existent. It was nearly the same. We conclude that this is not a very accurate way of determining the date of summer solstice. A place closer to the equator would be better, but how much better?

On the other hand, the megaliths of Senkoku allow a special beam of light to strike the side of stone A’ in the grotto. Most of the time, after clearing that side panel, the sunbeam lands on the floor of the grotto. Only on a few special days a year does it illuminate the “bumps” on the triangular face that the ancients had carved especially for this purpose. The arrival and end of the dashed spotlight is a delicate determinator of the summer solstice date.

We can marvel at the ingenuity of the ancient people who created with wonderful solar observatory using megaliths!

Lahaina Noon at Honolulu

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Honolulu, May 25, 2016.

Today, it is one day before the technical date of Lahaina Noon in Honolulu. See our previous post: https://okunomichi.wordpress.com/2016/05/07/1711/, which gives the date of May 26 at 12:28 HST for this event.

The above photo was taken at 12:27 pm HST clock time. It shows that the stop sign shows no shadow.

We have been wanting to take a photo such as this for a long time. So, please enjoy it with us.

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