M81 - Bode's Galaxy

M81 - Bode's Galaxy

The Object

Discovered by Johann Bode on 31st December 1774 (hence it’s popular name), Chaeles Messier immortalised it by including it the Messier Catalogue. M81 is a spiral galaxy lying ~12 million light years away from us, in the constellation Ursa Major (UMa). At the nucleus of the galaxy, there is a 70 million Solar-Mass supermassive black hole, and some evidence suggests this is orbited by a smaller secondary SMBH. In galactice terms, this is a close neighbour, and is extensively studied by professional astronomers.

Processing

All processing carried out in Pixinsight 1.9.3 Lockhart

WBPP - Calibration, local normalisation, sub-frame weighting, image registration and image integration. Auto cosmetic correction and debayering.

I split the L channel from the RGB and treated this separately before recombining as LRGB. The RGB image was treated with DBE, SPCC, SCNR, BXT and then Color Saturation. The image was then cloned and stretched with Masked Stretch and HT. A mask was made for the central core of the galaxy and applied to the clone.

HDRMT was used to increase the contrast before being blended back with PM. The Lum image was treated with BXT and then stretched.

ImageBlend script was used to bring the RGB and Lum together before final processing:

  • Colour Saturation
  • BXT
  • NXT

Acquisition

Acquisition was with an ASI Air - focusing, guiding and meridian flip all controlled by the device.

Calibration

Light frames calibrated with flats and 51 dark frames. Flat frames calibrated with 101 bias frames.