M101
M101, the “Pinwheel Galaxy” lies 21 million light years distant in the constellation Ursa Major. It spans 170,000 light years across (By comparison the Milky way is 100,000). It is occasionally referred to as the “Northern Pinwheel” to distinguish it from the other galaxy M33 with the same moniker but in the constellation Triangulum. M101 has an apparent size of 30’ x 27’ which is about the same as the full moon! It is a Hubble Type Sc galaxy with small central core and open spiral arms.
This galaxy interestingly contains 11 nebulae bright enough to have their own NGC numbers. I have uploaded a separate annotated image which shows most of these. Most likely the reason for this is that M101 has undergone tidal interactions with dwarf galaxies in its group. The galaxy NGC 5477 which is to the far right in the image is the leading suspect. The tidal interactions trigger collapse of numerous molecular clouds within M101 into active star-forming regions that produce massive blue type O and B stars. The blue giants emit ultraviolet radiation that ionizes the hydrogen gas within the clouds which produces bright emission nebulae known as HII regions. These are the brighter red-pink areas in the spiral arms. Many are large and bright enough to be visible through backyard telescopes!
Capture info:
Location: Orion’s Belt Remote Observatory, Mayhill NM
Telescope: Officina Stellare RiDK 400mm
Camera: SBIG STX 16803
Mount: Paramount MEII
Data: LRGBHa 4,3,3,4,4 hours respectively
Processing: Pixinsight 1.8-8-7
M101
M101, the “Pinwheel Galaxy” lies 21 million light years distant in the constellation Ursa Major. It spans 170,000 light years across (By comparison the Milky way is 100,000). It is occasionally referred to as the “Northern Pinwheel” to distinguish it from the other galaxy M33 with the same moniker but in the constellation Triangulum. M101 has an apparent size of 30’ x 27’ which is about the same as the full moon! It is a Hubble Type Sc galaxy with small central core and open spiral arms.
This galaxy interestingly contains 11 nebulae bright enough to have their own NGC numbers. I have uploaded a separate annotated image which shows most of these. Most likely the reason for this is that M101 has undergone tidal interactions with dwarf galaxies in its group. The galaxy NGC 5477 which is to the far right in the image is the leading suspect. The tidal interactions trigger collapse of numerous molecular clouds within M101 into active star-forming regions that produce massive blue type O and B stars. The blue giants emit ultraviolet radiation that ionizes the hydrogen gas within the clouds which produces bright emission nebulae known as HII regions. These are the brighter red-pink areas in the spiral arms. Many are large and bright enough to be visible through backyard telescopes!
Capture info:
Location: Orion’s Belt Remote Observatory, Mayhill NM
Telescope: Officina Stellare RiDK 400mm
Camera: SBIG STX 16803
Mount: Paramount MEII
Data: LRGBHa 4,3,3,4,4 hours respectively
Processing: Pixinsight 1.8-8-7