Halloween – short for All Hallows’ Eve – is an astronomical holiday. Sure, it’s the modern-day descendant from Samhain, a sacred festival of the ancient Celts and Druids in the British Isles. But it’s also a cross-quarter day, which is probably why Samhain occurred when it did. Early people were keen observers of the sky. A cross-quarter day is a day more or less midway between an equinox (when the sun sets due west) and a solstice (when the sun sets at its most northern or southern point on the horizon). Halloween – October 31 – is approximately midway point between the autumn equinox and winter solstice, for us in the Northern Hemisphere. The true cross-quarter day is actually November 7, a discrepancy of a week.

 

In other words, in traditional astronomy, there are eight major seasonal subdivisions of every year. They include the March and September equinoxes, the June and December solstices, and the intervening four cross-quarter days.

 

In modern times, the four cross-quarter days are often called Groundhog Day (February 2), May Day (May 1), Lammas (August 1) and Halloween (October 31).

 

For us in the Northern Hemisphere, Halloween is the darkest of the cross-quarter days, coming at a time of year when the days are growing shorter. Early people once said that the spirits of the dead wander from sunset until midnight around this cross-quarter day. After midnight , on November 1, which we now call All Saints’ Day , the ghosts are said to go back to rest.

It’s thought that the early forbearer of Halloween – Samhain – happened on the night that the Pleiades star cluster culminated at midnight.

 

That is, the Pleiades climbed to its highest point in the sky at midnight on or near the same date as this cross-quarter day. The midnight culmination of the Pleiades cluster now occurs on November 21, but back in the 11th and 12th century, Samhain and the midnight the Pleiades event would have taken place on or near the same date. At that time, when the Julian calendar was in use, the cross-quarter day and the midnight culmination of the Pleiades fell – amazingly enough – on or near October 31. If the Gregorian calendar had been in use back then, the cross-quarter day celebration would have been held on November 7.

 

The Pleiades cluster, also known as the Seven Sisters:

 

I'll show you some of my favorite "spooky" nebulae:

Does this not look like a scene out of a Tim Burton movie? This is the Ghost Nebula. It is one of the most evocative in the sky. It's part of a much larger molecular cloud in Cepheus and shines by the reflected light of embedded stars. LOVE this nebula!!! Happy Halloween astronomy enthusiasts.

 

The Ghost of the Moon Nebula (NGC 6781) in Aquila appears to hover mysteriously against the constellation's background stars.

 

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One of the more "striking" faces in the night sky. This is the Witch Head Nebula (IC 2118), a reflection nebula illuminated by the star Rigel.

 

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The Skull Nebula (NGC 246) in Cetus mimics the shape of a human skull with large purple eye sockets and an open mouth.

 

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The Phantom Streak Nebula, more prosaically known as NGC 6741, is a planetary nebula located about 7000 light-years away in the constellation of Aquila. Its central star, a white dwarf, has released its former atmosphere into space, where it glows eerily when excited by the dwarf's UV light.

 

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Sh2-68 is a feint planetary nebula... WITH TWO CREEPY LITTLE BEADY EYES!!!!

 

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NGC 1999 is a most unusual nebula. Astronomers used to think that the dark region in its center was a dark nebula, but according to a 2010 study, it appears to be a hole instead — an actual empty space! Call it the Spector of Death Nebula or the Grim Reaper Nebula , if you wish. Cowbell or not... I fear the Reaper!!!

 

Edited October 31, 20178 yr by Science Friction

Arachnophobes beware!!! Here is a Hubble-captured image of the stunning, yet spooky , Red Spider Nebula. Located some 3,000 LY away in the constellation Sagittarius, the RSN is a planetary nebula that has one of the hottest stars known to exist within it and contains winds that can generate waves 100 billion kilometers high.

 

Edited October 31, 20178 yr by Science Friction

Happy Halloween everyone!!! Keep reading the astronomy thread. We have an astronomical amount of fun in here. Sometimes, even a little "Spooky" fun.

 

https://www.youtube.com/watch?v=Y6QrAreY40c

Just in case you couldn't see those nebulae, here are some of them again.

Ghost of the Moon Nebula :

 

 

Witch Head Nebula:

 

 

Skull Nebula:

 

Phantom Streak Nebula:

 

 

Sh2-68:

 

Tomorrow night will see a dramatic full moon illuminate the sky( if we are lucky enough to have clear skies). This full moon is called Hunter's Moon, or Blood Moon. It's the first full moon since the Harvest Moon on October 5th and gets its name from the fact it would illuminate prey for hunters out stalking food during the cold winter.

 

 

It will provide a stunning sight for nighttime skygazers like you and I - although there is some debate surrounding whether or not this Hunter's Moon can also be classed as a supermoon. Supermoon debate aside, it should offer an impressive sight in tomorrow evening's sky, provided the clouds stay away.

 

A so-called supermoon appears when the moon is closer to Earth during the course of its orbit. The moon appears ever-so-slightly larger and brighter during this time.

The point at which the moon comes closest to the Earth is called its perigee - and this month that will occur on November 6th. Some say that's close enough to the Hunter's Moon to class it as a supermoon whilst others say it isn't so. Actually, December 2017 has a better claim to a supermoon as the full moon and the perigee will only be a day apart.

 

The reason for the name, you ask ??? Before tractors had headlights and with summer drawing to a close, farmers would use the light of the Harvest Moon to help them collect their crops after sunset.

 

But beyond the Harvest Moon, when all the crops were collected in, those same families would need to hunt for prey to sustain them through the winter. The next full moon after the Harvest Moon was termed the Hunter's Moon as they would use the moonlight to illuminate the prey. It's also sometimes called the Beaver Moon, because hunters used to set traps at this time of year, before waters froze over, to ensure a supply of warm furs for winter. I've also heard it called Frost Moon.

 

Hopefully, the clouds will part tomorrow evening and we will be able to view a nice big Hunter's Moon. That's what I call a perfect Friday Night Lights!!!

 

 

 

"For most people, we often marvel at the beauty of a sunrise or the magnificence of a full moon, but it is impossible to fathom the magnitude of the universe that surrounds us." Richard H. Bake

Early risers this morning looking towards the eastern sky about an hour before sunrise could have caught sight of two very bright white "stars" huddled together close to the horizon. The brightest point of light, of course, was Venus, sitting just 13 light-minutes from Earth, while its stellar companion, was the 250-light-year-away star Spica. Was anyone lucky enough to catch the shining planet-star duo this morning?