M 101 Pinwheel Galaxy
I done another version of M 101 in 2019 - HERE
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy distanced 21 million light-years (six megaparsecs) away in the constellation Ursa Major, first discovered by Pierre Méchain on March 27, 1781, and communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final entries.Pierre Méchain, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear.
William Herschel noted in 1784 that "[M101] in my 7, 10, and 20-feet [focal length] reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed."
Lord Rosse observed M101 in his 72-inch diameter Newtonian reflector during the second half of the 19th century. He was the first to make extensive note of the spiral structure and made several sketches.
To observe the spiral structure in modern instruments requires a fairly large instrument, very dark skies, and a low power eyepiece.
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.
It 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.They 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. (Note the 'pink' areas in my above image).
Imaging telescopes or lenses: Takahashi FSQ106ED
Imaging cameras: QSI 6120i
Mounts: Takahashi EM 400 Temma 2
Guiding telescopes or lenses: Takahashi FS 60 CB
Guiding cameras: QHY CCD QHY 5 II
Focal reducers: None
Software: PHD 2, Pleiades Astrophoto PixInsight , Sequence Generator Pro SGP
Filters: Astronomik LRGB & 6nm Ha
Accessories: Robofocus Focuser, ATIK EFW2
Resolution: 3035 x 1930
Dates: 9th Apr - 1st May '16
Frames:
Astronomik Lum: 4x300" + 32x600" bin 1x1
Astronomik Red: 3x300" + 15x600" bin 1x1
Astronomik Green: 3x300" + 13x600" bin 1x1
Astronomik Blue: 3x300" + 13x600" bin 1x1
Astronomik Ha 6nm: 5x900" bin 1x1
Integration: 14 Hours 30 minutes
Center (RA, Dec):(210.802, 54.351)
Center (RA, hms):14h 03m 12.394s
Center (Dec, dms):+54° 21' 04.260"
Size:61 x 38.8 arcmin
Radius:0.603 deg
Pixel scale:1.21 arcsec/pixel
Orientation:Up is -90 degrees E of N
William Herschel noted in 1784 that "[M101] in my 7, 10, and 20-feet [focal length] reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed."
Lord Rosse observed M101 in his 72-inch diameter Newtonian reflector during the second half of the 19th century. He was the first to make extensive note of the spiral structure and made several sketches.
To observe the spiral structure in modern instruments requires a fairly large instrument, very dark skies, and a low power eyepiece.
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.
It 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.They 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. (Note the 'pink' areas in my above image).
Imaging telescopes or lenses: Takahashi FSQ106ED
Imaging cameras: QSI 6120i
Mounts: Takahashi EM 400 Temma 2
Guiding telescopes or lenses: Takahashi FS 60 CB
Guiding cameras: QHY CCD QHY 5 II
Focal reducers: None
Software: PHD 2, Pleiades Astrophoto PixInsight , Sequence Generator Pro SGP
Filters: Astronomik LRGB & 6nm Ha
Accessories: Robofocus Focuser, ATIK EFW2
Resolution: 3035 x 1930
Dates: 9th Apr - 1st May '16
Frames:
Astronomik Lum: 4x300" + 32x600" bin 1x1
Astronomik Red: 3x300" + 15x600" bin 1x1
Astronomik Green: 3x300" + 13x600" bin 1x1
Astronomik Blue: 3x300" + 13x600" bin 1x1
Astronomik Ha 6nm: 5x900" bin 1x1
Integration: 14 Hours 30 minutes
Center (RA, Dec):(210.802, 54.351)
Center (RA, hms):14h 03m 12.394s
Center (Dec, dms):+54° 21' 04.260"
Size:61 x 38.8 arcmin
Radius:0.603 deg
Pixel scale:1.21 arcsec/pixel
Orientation:Up is -90 degrees E of N
Sky Plot
Annotated Image
Mono
