M100 - Mirror Galaxy
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Messier 100, also known as the Mirror Galaxy, is a spiral galaxy with clearly defined arms, located in the constellation Coma Berenices. The object was discovered on March 15, 1781, by the French astronomer Pierre Méchain, and barely a month later, on April 13, 1781, it was entered as the one-hundredth object in Charles Messier’s famous catalog.
M100 is among the most impressive and luminous members of the Virgo Cluster, a concentration of galaxies that forms the dynamical center of the Local Supercluster. This SAB(s)bc spiral galaxy lies at a distance of about 56 million light-years (17.2 megaparsecs) from Earth and has an estimated diameter of roughly 120 thousand light-years, making it comparable in size to our own Milky Way.
Observations
April 25, 2025, around 11:00 PM – Jaworzno, Poland
high level of light pollution
The night was clear, although the sky appeared slightly hazy.
M100’s hallmark is its symmetrical spiral structure, whose well-defined arms host vigorous star-formation regions. The galaxy shows signs of nuclear activity, and its core harbors concentrations of young, hot stars and emission nebulae. Data collected with space telescopes, including Hubble and Spitzer, have enabled astronomers to study its dust, gas, and stellar components in detail.
NGC 4312 is likewise a spiral galaxy, discovered by William Herschel on January 14, 1787. IC 783, by contrast, is a small lenticular galaxy.
These galaxies belong to the Virgo Cluster, which contains more than 1,300 identified galaxies—and possibly over 2,000 objects in total. It is the largest and nearest galaxy cluster relative to the Milky Way, forming the core of the entire Local Supercluster.
The galaxies of the Virgo Cluster interact continuously, generating secondary structures such as irregular galaxies, dwarf galaxies, and tidal tails. Radio observations of M100, for example, reveal distortions in the distribution of neutral hydrogen (H I), most likely caused by interactions with the intracluster medium or neighboring galaxies.
Bright and extensively studied, Messier 100 is a rewarding target for amateur observers using medium-aperture telescopes and a vital laboratory for professional astronomers investigating the evolution of galaxies.
Photo 1 Parameters:
- Total exposure time: 90 minutes (stack of 90 RAW frames at 60s each, using an appropriate number of dark, bias, and flat frames)
- ISO: 1600
- Maksutov-Cassegrain telescope (100/1400), prime focus exposure
- A filter was used to reduce the effects of artificial light pollution and atmospheric glow
- Mount: equatorial mount with tracking, aligned using the drift method and controlled by a custom-built system.
References:
- Sinnott R. W., The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer, Sky Publishing Corporation, 1988
- Wozniak H., et al., Double-barred starburst galaxies viewed by ISOCAM, The Universe as Seen by ISO, 1999, 427, pp. 989
- Chung A., et al., VLA Imaging of Virgo Spirals in Atomic Gas (VIVA). I. The Atlas and the H I Properties, The Astronomical Journal, 2009, 138(6), pp. 1741-1816
- Sakamoto K., et al., Bar-Driven Gas Structure and Star Formation in the Center of M100, The Astronomical Journal, 1995, 110(3), p. 2075
Marek Ples