Catching up with Messier 109 - A Spiral Galaxy

It's been quite a while since I updated my blog, nearly a year in fact. The latter half of last year and particularly the winter period wasn't very good for astrophotography because of the weather - we seemed to have weeks and weeks of cloudy skies with very few breaks. The winter constellations like Orion will have to wait for another year! 

It was very similar at the start of this year too, but things got a little better in February and March and I managed to make some progress in my images and image processing techniques. I've managed to keep posting a few things to my Flickr account throughout this time, and now I'm turning to my blog. I'm going to work from today backwards to post all the images I've taken since last May.

So here's an image of Messier 106 (also known as NGC 4258) whcih is an intermediate spiral galaxy in the constellation of Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is about 22 to 25 million light-years away from Earth and contains an active nucleus classified as a Type 2 Seyfert. The presence of a central supermassive black hole has been demonstrated from radio-wavelength observations of the rotation of a disk of molecular gas orbiting within the inner light-year around the black hole. A Type II supernova was observed in M106 in May 2014. Here's a closeup view of M106 cropped from the above image. It clearly shows the galaxy's spiral arms.

And finally this widefield view of my image has been annotated in www.astrometry.net and shows how rich the region is in deep sky objects including NGC 4217, a possible companion galaxy of M106.

Messier 51a - The Whirlpool Galaxy

Messier 51a, also known as the Whirlpool Galaxy or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation of Canes Venatici at a distance of 31 million light-years from Earth. It was the first galaxy to be classified as a spiral galaxy. 

It was discovered in 1773, by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in Messier's catalogue as M51. Its smaller companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance. In 1845, William Parsons using a 72-inch (1.8 m) reflecting telescope in Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one. These "spiral nebulae" were not recognized as galaxies until Edwin Hubble was able to observe Cepheid variables in some of these spiral nebulae, which provided evidence that they were so far away that they must be entirely separate galaxies.

The advent of radio astronomy and subsequent radio images of M51 unequivocally demonstrated that the Whirlpool and its companion galaxy are indeed interacting. Sometimes the designation M51 is used to refer to the pair of galaxies, in which case the individual galaxies may be referred to as M51a and M51b.

The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen from dark sky sites with binoculars. The Whirlpool Galaxy has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly that associated with the spiral arms) and galaxy interactions. This second version of my image is one that has been calibrated photometrically in Siril to give the true star colours.

Here's a widefield shot of the region which has been annotated in www.astrometry.net.