Ashbourne SKY WATCH week of 16 September
The nights are getting longer and deep sky and dim object observing is best from 9 pm to 5 am. After the weekend, the First Quarter Moon will disturb and the nights will be darker from midnight onwards. The Milky Way is in the zenith and best seen around midnight. Venus is getting further away from the Sun and is best seen in the early mornings from 3.35 am to 6.40 am in the constellation Cancer. Mars as well near the Sun and is best seen from 3.55 am to 6.10 am in the constellation Leo. The giant planet Jupiter gets away from the Sun and is best seen from 5.15 am to 6.25 am in the constellation Leo. The planet with the rings Saturn is best seen from 7.40 pm to 9.30 pmin the constellation Libra. For the planet Uranus you will need a binocular or smaller telescope and is best seen from 9.40 pm to 5 am in the constellation Pisces.
Look for the Gegenschein after midnight at about 1 am in the morning. It is a faint glowing patch of sky relatively good for observation 35° above the Southern horizon in the constellation Pisces. Sometime later, early morning at 5 am the Zodiacal Light is good for observation low above the Eastern horizon. Let us know if you have spotted!
The Sun rises at 6.38 am in the East and sets in the West at 7.17 pm. The Sun rises about 12 minutes later after a week and sets about 17 minutes earlier in the evening. On Wednesday 23 September at 9.20 am it is September Equinox. Monday 21 Septemberit is First Quarter Moon.
Wednesday 16 September
Today in 1662 the first recorded astronomical observation of the first Astronomer Royal was John Flamsteed's observation of a solar eclipse from his home in Derby at the age of 16, about which he corresponded with other astronomers. Flamsteed's interest in astronomy was stirred by the solar eclipse, and besides reading all he could find on the subject he attempted to make his own measuring instruments.
An Iridium flare appears at 8.39 pm in the South South East at an altitude of 37° in the constellation Aquila.
The International Space Station (ISS) appears at 4.57 am in the West at 33° high. ISS's highest point or culmination is a minute after at 4.58 am in the South South East at 51° altitude. ISS passes with 3 lunar diameters the bright star Aldebaran in the constellation Leo. ISS disappears at the horizon at 5.03 am in the East.
Thursday 17 September
Not visible as it is daytime, but at 4.42 pmthe planet Mercury is close to the star Spica in the constellation Virgo. Both have the same brightness and look for the pair in the early evening just after Sun set in the East.
A rather bright Iridium flare appears at 10.21 pm in the North East and 19° high in the constellation Auriga. A double Iridium flare, both very bright, appear at 4.30 am West South West at about 50° high in the constellation Andromeda. Worth to watch! A less bright flare is at 4.41 am in the South West at 29° high in the constellation Cetus.
The ISS appears at 5.38 am in the West at 14° high. Culmination at 5.41 am in the South at an altitude of 72°. ISS disappears at 5.46 am in the Eastern horizon.
Friday 18 September
The Moon's Earthshine is visible at 7.50 pm. A little later, at 8 pm the Moon is close to the star Zuben Elakrab. The limb separation is less than a degree or less than 3 lunar diameters. A little later, at about 8.45 pm, the Moon is North West of the planet Saturn. The limb separation is 4° or about 9 lunar diameters.
A flare is visible at 9.30 pm in the East South East at 69° high in the constellation Lacerta.
ISS comes out of the Earth shadow and appears at 4.47 am in the South West at 51° altitude. Culmination a minute later at 4.48 am in the South at 65° high where it passes very close the bright star Elnath/Al Nath in the constellation Taurus . ISS disappears at 4.53 am in the Eastern horizon.
Saturday 19 September
Today it is Astronomy Day.
Venus Brilliancy or is at its brightest at 1.20 pm. Look for the planet in the early morning before Sunrise!
At 7.50 pm the Moon's Earthshine is visible in the Western horizon.
A flare is visible at 8.51 pm in the North at 27° altitude in the constellation Camelopardalis. Later, at 10.18 pm, another flare is in the North East at 22° high in the constellation Perseus.
Watch the Great Red Spot on the giant planet Jupiter once it rises. Jupiter is best seen from 5 am to 6.30 am in the constellation Leo in the East North East.
ISS appears at 5.28 am in the West at 19° high. Culmination at 5.31 am at 70° altitude and disappears at 5.36 am in the Eastern horizon.
Sunday 20 September
The Moon's Earthshine is visible at 8.30 pm.
At 8.56 pm a really very bright Iridium flare appears in the East at 54° altitude in the constellation Andromeda.
ISS appears twice in the morning. Once at 4.37 am, when it comes out of the Earth shadow at 72° altitude in the South. ISS disappears at 4.43 am in the Eastern horizon. The second appearance, after one orbit of approximately 90 minutes is at 6.10 am in the West. Culmination is at 6.13 amin the South South West at 46° altitude and ISS disappears in the East South East at 6.19 am.
Monday 21 September
It is First Quarter Moon at 9.59 am. This is the Southernmost First Quarter Moon of the year. Former more Southern First Quarter Moon was on 12 September 2013. The next more Southern First Quarter Moon is on 9 October 2016.
The Moon is in maximum declination South at 1.01 pm. This is the lowest Southernmost Moon position of the last 1000 years, the 2nd lowest of the next 100 years, the lowest of the next 10 years, the lowest of the year, the lowest of the decade, and the 2nd lowest of the century. The next lower Southern Southernmost Moon position is on 22 March 2090.
The Moon is in maximum libration South at 3.22 pm. The South Pole of the Moon is tipped into the Earth's view. This is the Southernmost total libration of the year. Former more Southern total libration was on 2 December 2011. The next more Southern total libration is on 2 March 2016. At 7.35 pm the Moon is in maximum libration West. The Moon Crater Grimaldi is tipped into the Earth's view.
ISS appears at 5.19 am in the West at 26° high. Culmination at 5.20 am in the South South West at 59° altitude. ISS passes the star Procyon in the constellation Canis Minor (in translation “Little Dog”) with a separation of about 1°. ISS disappears at 5.25 am in the East South East horizon.
Tuesday 22 September
Today in 1955 the first commercial television broadcasting began in Britain by ITV (Independent Television).
ISS appears twice in the early morning. Once at 4.27 am in the South East at 50° altitude and disappears after a few minutes at 4.32 am in the Eastern horizon. After one orbit, ISS appears at 6 am in the West at 10° high. Culmination at 6.03 am in the South South West at 31°. ISS passes the bright star Rigel in the constellation Orion. Separation just over one degree. ISS disappears at 6.08 am in the South East horizon.
Wednesday 23 September
Today in 1973 the world's first Ceefax teletext service began on BBC Television.
At 9.20 am it is September Equinox.
The Golden Handle on the Moon is visible from 4.25 pm to 10.10 pm. The Sun rises on the Jura Mountains, while Sinus Iridium is still in the shadow. Use a binocular to observe. Moon rise in the East South East in the constellation Sagittarius and at 4.22 pm. The Sun sets at 7 pm in the West.
At 9.27 pm an Iridium flare in the East appears at an altitude of 65° and in the constellation Lacerta.
ISS appears at 5.09 am in the South West at 37° altitude. Culmination at 5.09 am in the South South West at 43° high. ISS passes the stars Alnilam and Alnitak very close, both in the constellation Orion. ISS disappears at 5.15 am in the East South East horizon.
Get in touch with me viawww.patrickpoitevin.weebly.com if you need more information.
Ashbourne SKY WATCH Special week of 16 September
September or Autumnal Equinox
It is that time of the year again … Summer is over. Well … summer … For what it was!
Equinox is twice a year. It is overall around the 21rst of March and around the 23rd of September. This year Spring equinox was on 20 March at 10.45 pm and Autumn equinox is on 23 September at 9.20 am.
What is equinox?
An equinox occurs when the plane of Earth's equator passes the center of the Sun. The two annual equinoxes are the only times when the sub solar point, the place on Earth's surface where the center of the Sun is exactly overhead, is on the Equator, and consequently the Sun is at zenith over the Equator. The sub solar point crosses the equator moving northward at the March equinox and southward at the September equinox. That is the official explanation …
In the past it meant day and night are approximately of equal duration. The word equinox comes from Latin aequus (equal) and nox (night). The equinox is not exactly the same as the day when period of daytime and night are of equal length for two reasons. Firstly, Sunrise, which begins daytime, occurs when the top of the Sun's disk rises above the Eastern horizon. At that instant, the Sun disk's center is still below the horizon. Secondly, Earth's atmosphere refracts sunlight. As a result, an observer sees daylight before the first glimpse of the Sun's disk above the horizon. To avoid this ambiguity, the word equilux is sometimes used to mean a day on which the periods of daylight and night are equal. Times of Sunset and Sunrise vary with an observer's location, meaning longitude and latitude. The dates when day and night are closest together in length depend on location.
For Ashbourne area on Wednesday 23 September at 9.20 am it is September Equinox and on Friday 25 September it is Sun Equilux at 7 pm. The latter is equal length of day and night for our location.
At an equinox, the Sun is at one of the two opposite points on the celestial sphere where the celestial equator and ecliptic intersect. These points of intersection are called equinoctial points: classically, the vernal point and the autumnal point. The equinoxes are the only times when the solar terminator is perpendicular to the Equator. As a result, the Northern and Southern Hemispheres are equally illuminated.
The September equinox occurs the moment the Sun crosses the celestial equator. It is the imaginary line in the sky above the Earth’s equator. It crosses from North to South. This happens either on September 22, 23, or 24 every year. This year it is 23 September.
The Earth's axis is always tilted at an angle of about 23.5° in relation to the ecliptic. The ecliptic is the imaginary plane created by the Earth's path around the Sun. On any other day of the year, either the Southern hemisphere or the Northern hemisphere tilts a little towards the Sun. But on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays.
On the equinox night and day is nearly exactly the same length. Which is 12 hours, and all over the world. This is the reason it's called an "equinox", derived from Latin, meaning "equal night". However, even if this is widely accepted it isn't entirely true. In reality equinoxes don't have exactly 12 hours of daylight.
In the Northern Hemisphere the September equinox marks the start of autumn. Many cultures and religions celebrate or observe holidays and festivals around the September equinox.
· The vernal equinox occurs in the Northern Hemisphere on March 19, 20, or 21. It marks the beginning of spring.
· The autumnal equinox occurs in the Northern Hemisphere on September 22 or 23. It marks the beginning of autumn.
· The equinox marks the two times each year when day and night are the same length in all parts of the world.
· An equinox is different from a solstice where the Sun hits its Northernmost or Southernmost position. Solstices mark the beginning of summer in June and winter in December.
· Easter always falls on the first Sunday after the first Full Moon after the vernal equinox.
Is autumn everywhere?
No way! We start calling this event the September equinox to avoid between equinoxes in the Northern Hemisphere versus Southern Hemisphere. It is because it is only autumnal in the Northern Hemisphere. In the Southern Hemisphere it marks the start of spring. The Spring Equinox is also called the Vernal Equinox.
It is getting colder after the September equinox? This is due to the tilt of the Earth. The Sun will shine more directly on the Southern half of our planet than it does on the Northern half. The Northern Hemisphere gets colder after this equinox as the Southern Hemisphere warms up. After all, less direct sunlight means less heat. But … you will not feel it so instantly after that day … There are numerous other meteorological reasons …
The days are getting shorter after the equinox? Yes they do, but ... they've actually been getting shorter after the Summer solstice. See my SKY WATCH where you will see Sun rise is getting later each day and Sun set is getting earlier each evening once after Summer solstice.
Autumn gets its own Full Moon called the Harvest Moon. From Wolf and Sturgeon to Hunter and Harvest, Full Moons are named for the month or season in which they rise. The Harvest Moon is the Full Moon closest to the autumn equinox. This year, the Full Moon is even a Super Moon and ... a Lunar Eclipse. Read this SKY WATCH Special next week!
Before artificial light farmers took advantage of the Full Moon's light to harvest their crops. In late summer and early autumn, many crops ripen all at once, making lots of work for farmers who had to stay in the fields after Sun set to harvest all the goods. Such moonlight became essential to their harvest, and the Harvest Moon emerged. So they say ...
The autumnal equinox falls on different dates each year, usually 22 September or 23 September like this year. In 1931 the equinox happened on 24 September. The Gregorian calendar doesn't match up perfectly with the position of Earth in its orbit around the Sun.
If the Earth would orbit around the Sun in exactly 365 days the Earth would be in its autumn equinox position on the same day each year. Since the Earth takes 365.25 days to make a complete journey around the Sun, the date is slightly different each year. The fall equinox won't happen again on 24 September until the year 2303.
Equinoxes are not to be confused with solstices, of which there are the summer and winter solstices. Solstices are also seasonal Sun points. Their name derives from the Latin for “sun stopped” meaning that the Sun “stops” at one point. The summer solstice is the longest day of the year and the winter solstice is the shortest day of the year.
Druids celebrate the autumn equinox. Equinoxes are important to many cultures around the world and were one a common cause for celebration in pre-Christian Europe. The most common cultural facet still attached to the autumnal equinox is the idea of “harvest” which is seen throughout the world from Korea to the Americas.
Do other planets have equinoxes? Just like the Earth other planets have equinoxes too. However planets like Saturn do not have annual equinoxes in the sense of Earth years. They are more random to our calendar, and the next equinox on Saturn will not occur until the year 2024. The last one was in 2009. They occur just the same with the planet changes its tilt on its axis and have been known to disrupt satellites orbiting Earth. Maybe we can travel to planets and go to summer places each time … Or just switch over from Northern to Southern Hemisphere on Earth …