A whole evening's viewing from Embsay, North Yorkshire on November 21st 2021.
See the night sky rotate, the moon rise and arc across the sky.
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Embsay Astronomy
Milan Davidovic
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The Night Sky
November 2021
Imagine you are stargazing on a dark, moonless evening. You scan the sky with your eyes maybe to try and spot the faint track of a meteor cutting across the sky. Then suddenly you are aware of a familiar star brightening. It illuminates more and more until it becomes the brightest in the sky, even brighter than a full moon and casting a shadow behind you. The following morning in broad daylight it is still visible! This actually did happen on July 4th just over a thousand years ago (no time at all in celestial time.) You would have witnessed the death throes of a dying lone star as it ignited into an amazing supernova. This is still visible now, although it is a smudge in a pair of binoculars, but with the right location and camera…wow! This is M1, or its common name The Crab Nebula.
Photo by Tim Jardine
There are many recorded supernovas in our history. It was thought that this particular blast was recorded by native American rock art but it is likely to have been another equally impressive event.
Here is the location of the Crab Nebula. It is very close to the area we looked at in last month’s article.
Looking East. November 4th at 11pm (or 18th at 10pm)
Supernova are not common. The dying star has to be of a particular size or fusion state to trigger an event of this type. In a typical galaxy only a small proportion fit this criterion, perhaps just three a century. In fact, the last one directly observed was over four hundred years ago. They are important as the huge amount of energy and material expelled can form the many elements we see and need around us today.
Looking South-November 4th 11pm (or 18th at 10pm)
As you will observe this month, Orion is now marching above the horizon in the East (chasing the Pleiades, remember...) The big Square of Pegasus is now a dominant feature of the night sky.
Planets
The Ecliptic is marked on my star chart above (Looking South). This is the path that the planets appear to follow and, due to their position and ours on the Earth, only the very faint Neptune and Uranus are currently high in our night sky. Jupiter is setting below the horizon.
Looking North -November 4th 11pm (or 18th at 10pm)
The view to the North should produce a beautiful Milky Way ‘arc’ overhead if we have a very clear moonless night on the 4th November. You will see Cygnus the Swan flying over the carpet of stars towards the West. Ursa Minor is pointing downwards, like the hand of a clock, having spun around Polaris over the year - indicating the arrival of autumn.
New Moon 4th November
Full Moon 19th November
Clear Skies
Milan Davidovic
- milandavidovic55
The Night Sky
October 2021
The Pleiades and Hyades.
Looking East this month, half way up in the night sky, sits the glorious Pleiades. You can see them clearly with the naked eye and appear as a very closely grouped set of stars that seem to glisten like an open jewellery box. They are also known as M45 or The Seven Sisters. What we are observing is an open cluster of over 1000 stars, six or maybe seven of which can be seen with the unaided eye. Unsurprisingly, because of their prominence, they appear in many cultures and many legends and myths surround the cluster. One legend from the native Americans has it that seeing five stars you have normal eyesight, but seeing all seven you had the sight of a warrior. The Greek myth is that seven daughters of Atlas (busy holding up the sky!) were seen by a hunter (Orion) who chased them, then Zeus intervened by placing them in the sky. Over the next few months Orion becomes visible above the horizon and his belt, the three central stars, clearly point towards those poor daughters he is said to be chasing!
Photo Jim Thommes
An astronomer in 1761 calculated that the chances of so many prominent stars in the Pleiades being aligned together was one in half a million. He then concluded that they all must be physically related somehow. Nowadays we know that they are locked together moving through space but eventually will disperse.
Just below the Pleiades cluster, but currently above the horizon in the East is what looks like a small side-on ‘V’ shape. The bottom part of this contains a very bright star called Aldebaran. This area is called the Hyades cluster, again containing many hundreds of stars, the brightest form the head of Taurus the bull. Although Aldebaran appears to be part of the cluster of stars in this area it is just a trick of the eye and is located in a different region of space.
Looking East from Embsay on 6th October (New Moon) at 10pm
Aldebaran is a red giant and our own sun will become such a star one day. It is a dying star which has expanded to engulf any inner planets. When this phase is complete it will have exhausted all of its fuel and its outer layer will be blown away. It will then shrink to become a white dwarf. Currently Aldebaran has expanded so that its outer core is 44 times that of our sun.
But it is still not a massive star compared to others!
Diagram-Dave Jarvis
Other things to look out for this month are early evening Venus in the South West (9th October) and Jupiter plus Saturn low in the SE (14th October).
Clear Skies
Milan Davidovic
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