M100 - Spiral Galaxy in Coma Berenices


M100 (NGC4312) - Spiral Galaxy in Coma Berenices
Mag 9.3 RA 12:22.9 Dec +15 49 7x6 arcminutes


Discovered by Pierre Méchain in 1781.

On March 15, 1781, Pierre Méchain discovered this object, M100, together with its apparent neighbors, M98 and M99 (not shown in the above photo). His friend, Charles Messier, obtained its position on April 13, 1781, and included it in his catalog, immediately before finishing the third, final published edition.

M100 is one of the brightest member galaxies of the Virgo Cluster of galaxies.

M100 is a spiral galaxy, like our Milky Way, and tilted nearly face-on as seen from earth. It is among the first spirals that have been discovered, and listed by Lord Rosse as one of 14 "spiral nebulae" discovered to 1850. The galaxy has two prominent arms of bright blue stars and several fainter arms. The blue stars in the arms are young hot and massive stars which formed recently from density perturbations caused by interactions with neighboring galaxies which are lying just outside our image. Despite its nearly perfect symmetric outline, this galaxy appears slightly asymmetric, as on the southern (lower) side of the nucleus more (or brighter) young stars have formed.

Scope: Planewave 12.5" CDK
Camera: Apogee U16M w Gen II Astrodon LRGB filters
Mount: Paramount ME (MKS5000 upgrade)
Guiding: ST-402ME and Astrodon MMOAG
Luminance 8 x 10 min
RGB 9/5/7x10 min
Acqisition via TSX and CCD-Commander
Aligned and individual channels combined in Maxim; Colour combines redone in RegiStar
Colour processing in PS CS4
Gradient removal using Russ Croman's GradientXTerminator

Click on the image to see a larger version.

Lucknow, Ontario
April 25 2015