Messier 100, also known as NGC 4321 or the Mirror Galaxy, is a grand design intermediate spiral galaxy located in the southern region of the Coma Berenices constellation. It is one of the brightest and largest galaxies in the Virgo Cluster, situated approximately 55 million light-years from our galaxy. Messier 100 has a diameter of 107,000 light-years, making it about 60% as large as the Milky Way. Pierre Méchain discovered the galaxy in 1781, and it was subsequently cataloged by Charles Messier 29 days later in his compilation of nebulae and star clusters. As one of the first spiral galaxies identified, Messier 100 was listed among fourteen spiral nebulae by Lord William Parsons of Rosse in 1850. The galaxy has two satellite galaxies, NGC 4323 and NGC 4328, with NGC 4323 being connected to it by a bridge of luminous matter. 

101 x 10 sec subs.  Processing in Siril and GraXert. 15 May 2024.  Inner city star seeing stars down to 17mag!

Object: M101

Location: Portsmouth, UK

Mount: Alt Az

Bortle Scale: 45 Minutes

Total Session Time: 10 Minutes

Nights:       15th May 2024

Total Subs Used: 101 x 10 Subs

Seeing:  High Cloud

Fits Stacked: Siril 

Post-Processing Steps

1. GraXpert - Background extraction and Denoise v2.0 

2. Siril - color calibration, photometric color calibration,remove green noise, color calibration, histogram stretch, colour saturation.