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Messier 51 M51 NGC 5194, Canes Venatici (Whirlpool Galaxy)

Astrophotography CCD CMOS DSLR DSO Filters Imaging Orion Refractor



Messier 51 M51 NGC 5194, Canes Venatici (Whirlpool Galaxy)

Messier 51 M51 NGC 5194, Canes Venatici (Whirlpool Galaxy)

M51A (NGC5194) was discovered by Messier on October 13, 1773 while cataloguing nebulous objects which might be mistaken for comets. The small companion galaxy, M51B (NGC 5195) was first documented by Mechain in 1781. In 1845 this nebula was the first in which Earl of Rosse recorded a spiral structure with his large 72 inch reflector in Ireland. The meaning of spiral nebulae remained unclear until Edwin Hubble identified them as separate galaxies through distance measurements using Cepheid variables. More recently, radio telescopes defined M51 as a Seyfert galaxy, emitting strong radio signals from its bright, active core. In 1992 and 2005 high resolution Hubble images revealed two nearly perpendicular dust rings most likely orbiting a massive black hole in the galactic center. The attached photograph clearly shows spiral arm deformation along the E and N quadrants of M51A caused by gravitational interaction during a close passage of the smaller galaxy M51B about 550 million years ago. The smaller component appears to be gravitationally captured by the larger galaxy, and the two will eventually merge over hundreds of millions of years.

The larger component of M51 has an angular diameter of 11.2 arcmin and apparent magnitude of 8.4 - visible in binoculars under good sky conditions. The distance is estimated at 22 million LY, the diameter at 70 thousand LY, and the mass at 160 billion solar - about one third the mass of the Milky Way.

In addition to the main target, the image contains small galaxies IC 4278, NGC 5198, IC 4263, NGC 5169, PGC 91291, and PGC 2299047. SIMBAD and NED databases indicate that the field is also strewn with numerous quasars, all of which are fainter than the limiting magnitude of 18, and therefore failed to record.

Image details:
-TSapo100q astrograph, Sigma APO 1.4x tele-extender, 100 x 812mm
-Modified Canon T3i camera, Astronomik CLS-CCD filter
- Celestron AVX mount, Orion 60mm F4 SSAG pro autoguider
-7 x 240 sec subexposures, iso 1600, 30 darks, 30 bias, 2x drizzle, 50% area crop, processed as RGG
-Software PHD2, DSS, XnView, StarNet++, StarTools v 1.3 and 1.7

Total integration time on this image is only 28 minutes. I had been planning to get around 2 hours, but I lost an argument with clouds. Still, the image came out better than I expected.

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