Remnants

Crab Nebula; Nov 22, 2022

The year was 1054. Emperor Renzong of the Song Dynasty reigned in China out of the capital city Kaifeng on the southern banks of the Yellow River. On the 4th of July, at the break of dawn, a bright star burst into view in the sky in the constellation of Taurus. It was so bright, it could be seen during daytime. It remained visible for 23 days during the day.  The star faded slowly over time and on 6 April 1056, 642 days or nearly two years later it disappeared from view. The Chinese wrote about it, as did the Japanese and Arabic astronomers.

Today, a thousand years later, a tenuous wispy cloud is all that remains in place of the progenitor star, now known as the Crab Nebula or Supernova Remnant 1054. 

Simulated image of supernova SN 1054 at the position 

of modern Crab Nebula, as presumably would have 

been observed from capital of Song Dynasty at Kaifeng.
Source: Wikipedia. 

In modern times, the Chinese "guest star" event came to be identified as a supernova, a spectacular stellar explosion. This is one of the few galactic supernovae where the date of explosion is well known thanks to historical records.  But the millennia old connection was not trivial and took some of the brightest minds in modern times to figure out.

Connecting the Dots

In 1758, seven hundred years after the event, French astronomer Charles Messier was searching for the predicted return of Halley's comet that year with his four inch telescope from his downtown Paris observing station. He noted this fuzzy object in Taurus which did not move across the stellar backdrop like comets should.  To avoid future confusion, he put this down as the first item in his now famous catalog of non-comet distractions. Hence the Crab nebula is also known as Messier 1 or M1. 

Edwin Hubble.
Source: Encyclopedia Britannica

Another two hundred or so years passed. before in 1928, the American astronomer Edwin Hubble suggested that this might be the "guest star" remains from 1054 . Hubble's suggestion was based on the  evidence found in 1921 that the cloud was expanding in size and the rate of expansion estimated by comparison with older photos, pegged its beginnings to be some 900 years in the past.  

This estimate was refined using spectroscopy in 1942 by Nicholas Mayall, a wannabe mining engineer turned astronomer at the Lick observatory in California and his collaborator Dutch radio astronomer Jan Oort by studying the Chinese historical records of the guest star more closely.

A curious quest that began in Chinese riverbanks completed a full circle a thousand years later at the American west coast, aided by a Frenchman and a Dutch along the way.

The Crab’s Beating Heart

GFDL movie of the Crab Pulsar |

Source=http://www.ast.cam.ac.uk/~optics/Lucky_Web_Site/

|Date=07 Aug 2007 |

Author=Cambridge University Lucky Imaging Group

At the center of the Crab nebula is a spinning, relatively young neutron star. This is the stellar core that remained after the nova blew out its outer layers. Relativistic X-Ray jets beam out of it, crossing paths with the earth 30 times every second as it spins.  This is known as the Crab Pulsar.

A thousand years after creation, the Crab is still young at heart!

This image is the largest image ever taken with Hubble Space Telescope and assembled from 24 individual exposures and

is the highest resolution image of the entire Crab Nebula ever made. Source Hubble Space Telescope Images

Imaging Evolution 

Crab Nebula, Mar 18, 2020

The original picture to the left taken on March 18, 2020 used the same telescope and imaging camera but only short 30 second exposures, the maximum possible on my old altitude-azimuth style mount. 

The first update is now the picture at the bottom of this post was updated with an integration of images acquired over two days in December of 2021. Each image was 5 minute long totalling to over 2 hours of total exposure, made possible by my new equatorial style mount and guiding rig.  

The second update which is now on the top of this page is a new image acquisition using the newly purchased dedicated astronomy camera, ZWO ASI 294MC Pro. The total integration time was about 90 mins with exposures being 31X180s. As one can see that while the capture time has come down by 30 mins (out of 2 hrs) - the image quality and color has significantly improved compared to the Dec 2021 image.  

The difference increased exposure time can make with the same scope, is quite drastic. However the oldest image from 2020 is closest to what one would see visually through a mid size telescope.  

Crab Nebula (M1) - Dec 2021

Imaging Details (Dec 2021):

____________________________________________________

Crab Nebula, Dec 13, 21, 2021, New Jersey

Canon 70D

Day 1: 21 X 300s light, 10X dark, 23 Bias ISO 800 

Day 2: 5 X 300s light, 5X dark, 5 Bias  ISO 800 

Celestron 127 mm Mak-Cass scope  with 0.6X focal reducer

Celestron AVX mount, Orion 50mm guidescope and ZWO ASI 120 mm camera

CPWI, PHD2, NINA, Deep Sky Stacker, Topaz AI  and GIMP