M91+ 2017-01-31T10:52:41+00:00

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M101 (NGC 5457) Pinwheel Galaxy

Galaxy, Ursa Major
Mag 7.86 Size 28?.8 × 26?.9
200mm f8 RC
Piggyback guiding with 70mm f/7 refractor
L 20×240s 2×2, RGB 10×120s 4×4 Darks Bias Flats
Atik 460EX (-24C), LRGB filters, IDAS P2 LPR filter
Captured in APT, Processed in Nebulosity3, PS CC, LightRoom

Horrible gradients again. I suspect collimation and camera alignment need some work.

M101 is a large galaxy comparable in size to the Milky Way. With a diameter of 170,000 light-years it is roughly equal the size of the Milky Way. It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.

M101 is noted for its high population of H II regions, many of which are very large and bright. H II regions usually accompany the enormous clouds of high density molecular hydrogen gas contracting under their own gravitational force where stars form. H II regions are ionized by large numbers of extremely bright and hot young stars; those in M101 are capable of creating hot superbubbles. In a 1990 study, 1264 H II regions were cataloged in the galaxy. Three are prominent enough to receive New General Catalogue numbers – NGC 5461, NGC 5462, and NGC 5471.

M101 is asymmetrical due to the tidal forces from interactions with its companion galaxies. These gravitational interactions compress interstellar hydrogen gas, which then triggers strong star formation activity in M101’s spiral arms that can be detected in ultraviolet images.

In 2001, the x-ray source P98, located in M101, was identified as an ultra-luminous X-ray source – a source more powerful than any single star but less powerful than a whole galaxy – using the Chandra X-ray Observatory. It received the designation M101 ULX-1. In 2005, Hubble and XMM-Newton observations showed the presence of an optical counterpart, strongly indicating that M101 ULX-1 is an x-ray binary. Further observations showed that the system deviated from expected models – the black hole is just 20 to 30 solar masses, and consumes material (including captured stellar wind) at a higher rate than theory suggests.

27 March 2017|Galaxy, M91+, News|

M97 (NGC 3587) Owl Nebula

Planetary Nebula, Ursa Major, Owl Nebula
Mag 9.9, size 3.4’x3.3′
200mm f8 RC
Piggyback guiding with 70mm f/7 refractor
L 22×240s 2×2, RGB 11×120s 4×4 Darks Bias Flats
Atik 460EX (-25C), LRGB filters, IDAS P2 LPR filter
Captured in APT, Processed in Nebulosity3, PS CC, LightRoom

The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula located approximately 2,030 light years away in the constellation Ursa Major. It was discovered by French astronomer Pierre Méchain on February 16, 1781. When William Parsons, 3rd Earl of Rosse, observed the nebula in 1848, his hand-drawn illustration resembled an owl’s head. It has been known as the Owl Nebula ever since.

The nebula is approximately 8,000 years old. It is approximately circular in cross-section with a little visible internal structure. It was formed from the outflow of material from the stellar wind of the central star as it evolved along the asymptotic giant branch. The nebula is arranged in three concentric shells, with the outermost shell being about 20–30% larger than the inner shell. The owl-like appearance of the nebula is the result of an inner shell that is not circularly symmetric, but instead forms a barrel-like structure aligned at an angle of 45° to the line of sight.

The nebula holds about 0.13 solar masses of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur; all with a density of less than 100 particles per cubic centimeter. Its outer radius is around 0.91 ly (0.28 pc) and it is expanding with velocities in the range of 27–39 km/s into the surrounding interstellar medium.

The 14th magnitude central star has since reached the turning point of its evolution where it condenses to form a white dwarf. It has 55–60% of the Sun’s mass, 41–148 times the brightness of the Sun, and an effective temperature of 123,000 K. The star has been successfully resolved by the Spitzer Space Telescope as a point source that does not show the infrared excess characteristic of a circumstellar disk.


1 March 2017|M91+, News, Planetary Nebula|

M96 (NGC 3368)

Spiral Galaxy Leo
Mag. 10.1, size 7.6′ x 5.2′
200mm f8 RC, piggyback guiding C80ED
10×120, 20×180 ISO 1600, darks, flats
Canon EOS 350D modded, Astronomik CLS
Captured in APT, Processed in Nebulosity, PS CS5

Not a great night or image. Needed longer subs but sky wouldn’t allow.

24 March 2014|Galaxy, M91+|