On this page a 35°×25° wide-field view of the Milky Way in constellations Perseus, Camelopardalis and Cassiopeia is presented in different color composites.
This region is full of known and unknown nebulae.
Click on the images to load a full resolution version with more than 100 megapixels using a JavaScript viewer.
Selected details
Here are a few details that also can be seen using the JavaScript viewer.
Discoveries
The views above show many HII regions that cannot be found in catalogs. (The JavaScript Viewer allows identifying objects using catalogs or SIMBAD and defining new objects.)
Some (probably not all) of these unexplored nebulae have been collected in the list below. Click on the following links for a presentation.
In the JavaScript viewer, the object outlines can be toggled on and off by pressing the '2' key. This can be helpful to make certain structures (e.g. rings) visible.
False color images containing H-alpha and continuum:
H-alpha is mapped to red, blue continuum is mapped to green, and red continuum (without H-alpha) is mapped to blue.
Color of molecular clouds and reflection nebulae in the false color image is something between green (bluish in reality) and blue (reddish in reality).
HII regions (ionized hydrogen) appear red to orange, depending on the amount of OIII (doubly ionized oxygen) detected by the blue continuum filter.
SIMBAD queries for certain object types can be made easily in the JavaScript Viewer by drawing a circle and pressing a shortcut key or via the menu
A repository with the discoveries can also be found on GitHub
Image data
Images where captured with a camera array which is described on the instruments page.
Image data are:
Projection type:
Stereographic
Center position:
RA: 3h28m, DEC: 57°
Orientation:
Above:
North is right
JavaScript viewer:
North is up
Scale:
10 arcsec/pixel (in center at maximum resolution)
FOV:
35°×25° (RA×DEC, through center)
Exposure times:
Sum of exposure times of all frames used to calculate the image.
H-alpha:
8.7 d
Continuum channels:
5.3 d
Image processing
All image processing steps are deterministic. There was no manual retouching or any other kind of non-reproducible adjustment.
No AI was used; the images shown here are the results of deterministic calculations and not hallucinations of an AI.
Image processing steps where:
Bias and dark current subtraction, flatfield correction, noise estimation
Alignment and brightness calibration using stars
Stacking with masking unlikely values and background correction
Extracting stars from the emission line images using information from continuum images
Denoising and deconvolution both components (stars and residual)
RGB-composition (same factor for stars and residual for the true color composite)
Dynamic range compression using non-linear high-pass filter
Tonal curve correction
References
Dominic Lagrois and Gilles Joncas.
On the Dynamical Evolution of H II Regions: An Investigation of the
Ionized Component of W4, A Galactic Chimney Candidate. II. Kinematics and
Dynamics in the Latitude Range 3°; < b <= 7°.
ApJ, 693(1):186–206, March 2009.
[ DOI ]