07-07-2024, 10:15 PM
The constellation of Cygnus (The Swan) -- sometimes called the Northern Cross, is easily visible. Within this constellation there is a large nebula, NGC7000 (The North American Nebula, since it looks like North America). Part of this nebula complex has an area that is called the Cygnus Wall.
The Cygnus Wall is an area of active star formation.
Here is the image of the Cygnus Wall
I've recently added some additional filters that are used for NarrowBand astrophotography. There are 3 specific filters that block most light except for a very narrow band of light at specific frequencies (colors), thus the name "NarrowBand". The Hydrogen Alpha filter is specific for a deep red color, the Sulfur II filter is specific to a very very deep red, almost infrared, and the Oxygen III filter is specific to a blue/teal color.
In order to make an image using narrowband filters, each of the images taken by a specific filter is assigned to either the Red, Green, or Blue (the primary colors that our eyes see). One of the combinations is what is called the "Hubble Pallet", since many of the pictures that the Hubble takes are using these same types of filters. Here the Sulfur II images are assigned Red, Hydrogen Alpha is assigned Green and Oxygen is assigned Blue. This results in what is called a false color image which makes it easy to see where these different gases are located. The image above is fairly close to the natural colors that one would see if our eyes were able to see such a dim image.
The darker areas are dust and possibly other gases that are not emitting light (or light that is the right frequency).
BTW -- All the images from the James Web Space Telescope are also false color. The images from the JWST are in the far infrared color which is invisible to our eyes. They are using the same concept, assigning specific filters to the Red, Green, or Blue channel of the image.
The Cygnus Wall is an area of active star formation.
Here is the image of the Cygnus Wall
I've recently added some additional filters that are used for NarrowBand astrophotography. There are 3 specific filters that block most light except for a very narrow band of light at specific frequencies (colors), thus the name "NarrowBand". The Hydrogen Alpha filter is specific for a deep red color, the Sulfur II filter is specific to a very very deep red, almost infrared, and the Oxygen III filter is specific to a blue/teal color.
In order to make an image using narrowband filters, each of the images taken by a specific filter is assigned to either the Red, Green, or Blue (the primary colors that our eyes see). One of the combinations is what is called the "Hubble Pallet", since many of the pictures that the Hubble takes are using these same types of filters. Here the Sulfur II images are assigned Red, Hydrogen Alpha is assigned Green and Oxygen is assigned Blue. This results in what is called a false color image which makes it easy to see where these different gases are located. The image above is fairly close to the natural colors that one would see if our eyes were able to see such a dim image.
The darker areas are dust and possibly other gases that are not emitting light (or light that is the right frequency).
BTW -- All the images from the James Web Space Telescope are also false color. The images from the JWST are in the far infrared color which is invisible to our eyes. They are using the same concept, assigning specific filters to the Red, Green, or Blue channel of the image.