M1 is a gas cloud which is the remnant of a huge star which exploded into a supernova, the light from which reached us in the year 1054 A.D. The original star, with perhaps ten times the mass of our Sun, remains at the center of this nebula, but it now contains perhaps 1.5 times the mass of our Sun, and has collapsed into a neutron star, with a diameter of ten miles, which rotates on its axis 30 times per second. The outer layer of gas is expanding at a rate of about 3 million miles per hour. It is about 6,500 light years from the Sun. At that distance, it is about 12 light years across (giving a little bit of evidence of the power of a supernova explosion, pushing matter six light years away in only 1000 years).

An interesting phenomenon that this image shows is the shockwave created by the rapidly-spinning neutron star (a pulsar wind nebula) at the center of the nebula. In the image below, the pulsar wind nebula is manifested in the two curved bright arcs above and below the two bright stars at the center of the image; this little image is a crop of the center of the full image.


This is the second time I have imaged this striking object; the first was twenty years earlier, from my yard. To see what better location (darker skies; less turbulent skies), better equipment, and more skill (and, yes, better software) can do, compare this image to that effort.

Technical Information:

(HaL)(HaR)(OIIIG)(OIIIB): 630:630:594:180:240:280 (a total of almost 42 hours of exposures); luminance layer consists of blend of 36 fifteen-minute images using a luminance filter and 21 thirty-minute images using an Ha filter; R channel is a blend of Ha data also used in the luminance layer and 12 fifteen-minute images using a red filter; G consists of a blend of 16 fifteen-minute images taken through a green filter and 21 thirty-minute images taken through an OIII filter, while B is the blend of 14 twenty-minute images taken through a blue filter and the OIII data.

Equipment: RC Optical Systems 14.5 inch Ritchey-Chrétien carbon fiber truss telescope, with ion-milled optics and RCOS field flattener, at about f/9, and an SBIG STX-16803 with internal filter wheel (SBIG filter set), guided by an SBIG AO-X/STX Guider, all riding on a Bisque Paramount ME German Equatorial Mount.

Image Acquisition/Camera Control: Maxim DL, controlled with ACP Expert/Scheduler, working in concert with TheSky X.

Processing: All images calibrated (darks, bias and sky flats), aligned, and combined in Pixinsight. Color combine in Pixinsight. Ha and OIII data blended into the broad band channels in Pixinsight. Some finish work (background neutralization, color calibration, deconvolution (Blur XTerminator), gradient removal, Noise XTerminator for noise reduction, done in Pixinsight; some finish work (LRGB combination, saturation adjustment) was done in Photoshop CC.

Location: Data acquired remotely from Sierra Remote Observatories, Auberry, California, USA.

Date: Images taken on many nights during the 2022-2023 and 2023-2024 winters. Image posted July 11, 2024.

Date: Image scale of full-resolution image: 0.56 arcseconds per pixel.

Seeing: Generally good--caliberated luminance images varied from 1.7 arcsecond FWHM to 2.7 arcsecond FWHM.

CCD Chip temperature: -25C

Copyright 2022, 2023, 2024 Mark de Regt

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