Messier 106 (NGC 4258) - wonderfuluniverse.de

Messier 106 (NGC 4258) from my backyard

In 2011 I captured Messier 106 from my backyard in Krefeld using my DSLR setup, gathering roughly 6 hours of exposure time under suburban skies. Despite the limitations, the data already revealed the galaxy’s striking asymmetric spiral structure. A few years later, in 2014, I returned to this target with a CCD camera, accumulating nearly 20 hours of integration. Even though the sky conditions were still light-polluted, the significantly deeper exposure uncovered much finer details—faint outer arms, numerous H II knots, and subtle structural irregularities.

Scientifically, Messier 106 (NGC 4258) is one of the most fascinating nearby spiral galaxies. Located about 23 million light-years away in Canes Venatici, it is classified as a Seyfert II galaxy and belongs to the small class of anomalous-arm spirals. Unlike typical spiral arms shaped solely by density waves, M106 exhibits additional arms that emit strongly in radio, X-ray, and Hα wavelengths.

These “anomalous arms” are powered by jets and shock heating from the galaxy’s actively accreting supermassive black hole, making M106 an important laboratory for studying AGN feedback in relatively normal disk galaxies. The galaxy is also famous for hosting water megamasers in its nucleus—natural cosmic lasers that allow exceptionally precise geometric distance measurements. This has made M106 a crucial anchor point for calibrating the extragalactic distance scale and refining the value of the Hubble constant.

Combining my datasets from 2011 and 2014 demonstrates just how much deep integration can reveal in a galaxy like M106, where both classical spiral structure and unusual nuclear activity coexist in a single, visually impressive object.

Data calibration and registration was performed with DeepSkyStacker, the final processing was done with PixInsight. The result was as follows:

Here is an overview of the used equipment and the exposure times:

Date: 2014
Location: Krefeld, Germany
Telescope/Lens: 10″ Newton ohne Namen
Focal length [mm]: 1000
Focal ratio: 4
Mount: Losmandy G11
Camera: Moravian 8300FW
Filter: L:R:G:B:Hα
Exposure time [min]: 615:110:115:115:165
Resolution: 1.11″/px

For the 2011 data the calibration and registration was performed with DeepSkyStacker, the final processing was done with PixInsight. The result was as follows: