NGC7000 imaged last night in backyard, Portland Oregon
95 minutes of imaging (minimal)
Processed in SHO (RGB mapping with SulphurII, Ha, OIII filter data).
Any appreciated, color comments , etc.
ASI294 Color astro camera with Williams gt71 scope (678MM)
Stack in Astropixel, PP in Capture, Affinity, Pixinsight, Photoshop.
I see why they named it as they did. Nice one, Dan. I think this one works quite well. Excellent.
Very nice! You have pulled out good detail with well-controlled noise in the darks. What a look into a world that is otherwise hidden from us.
Nebula are clouds of dust/gas left from explosions of dying stars in our galaxy. This one is in our back yard, at about 200 light years away. If we could view these objects on a cosmic time scale, they would be areas of wild roiling violence, as we might infer from the convoluted structures.
Nebula are in part illuminated by their own energy but more often by a nearby star, whose high-energy (UV) component of its radiation strikes the free-floating molecules in them and causes them to emit photons at specific wavelengths for different molecules. Hydrogen is most common, then helium, with traces of heavier elements such as oxygen, nitrogen, sulfur… Varying densities of tiny “dust” particles (aggregates of denser molecules) block light to provide darker features. The brightest star on the left (Deneb) is about the same distance but is apparently not thought to be the source of illumination. The star near the UR “rule of thirds” point is said to be the energy source for this nebula.
Nebula are very large and the closer ones can be captured by a quality backyard telescope, but most of their structure is very dim. The narrow range of wavelengths captured by the three filters Dan uses blocks the wavelengths of our terrestrial light pollution and allows these amazing structures to be seen, but at the cost of a very low signal-to-noise ratio. The images need to be rendered by multiple (up to hundreds of) exposures to reduce noise. The exposures also need to be long – in the range of minutes – so the object needs to be tracked very accurately as it moves across the sky. And then sophisticated processing is used to bring up contrast and detail. The “false” colors are from assigning different colors to the spectral lines.
There are quite a number of Nebula (maybe comparable to duck species), so Dan can stay quite busy capturing them.
