Planewave CDK12.5 telescope; AP 1100GTO Mount
QHY600M Camera, - Antlia Pro Broadband Filters
R,G,B: (14,14,14 x 150s, Bin 1, Gain 26)
H,O,S: (43,34,33 x 600s, Bin 1, Gain 26)
Total integration time = 20.1 hrs (Jun 10,14,15,16,18,23,25,28,30, Jul1,3,4 2025)
Vancouver Island, BC, Canada

For a couple of years, I had wanted to image M16, the Eagle Nebula and, in particular, the "Pillars of Creation" from my back yard. However, the is a line of gigantic Douglas fir trees to my south that obscure my southern horizon. These tree are also growing, so I was determined that 2025 would be the year. Across a month's elapsed time, with weather less than cooperative, I managed 20 hours of integration time, as M16 peeked through the trees. At least I can check this target off my bucket list.
I recently completed an ambitious posting on my website (APRealspace.com) using astrophysical data to determine the properties of the common gases the make up our universe. For earthbound scientists and engineers, this listing of properties and conditions that define pretty much all the nebula and galaxies that we like to image. Stellar Nurseries, like the Eagle Nebula is no exception. Almost everything we need to fully understand what is going on these stellar birthplaces are these properties and the appropriate physical equations to apply. Almost, because our understanding must include the interactions and thermodynamics between our gases and electromagnetic radiation.
This leads us to two foundational, but seemingly unrelated physical concepts that were put forward by one scientist by the name of G.G. Stokes, whom I am not sure was even interested in stellar nurseries or astrophotography.
Our image of the Eagle Nebula is a result of hydrogen photoluminescence - the process is the absorption by hydrogen atoms and molecules of a photon that stimulates it, and sends the hydrogen into a higher energy state. Upon returning to its ground state, hydrogen will emit one (or more) photons of in lesser energy (longer wavelength(s)) than the one adsorbed. The difference in energy between the absorbed and emitted photons is a form of red-shift, that has led to the development of Raman spectroscopy and solar voltaic cells. The difference between absorbed and emitted energy is manifested as heat either in the vibrational and translational movement of the atom or molecule. A rule first put forward by Stokes.

In the case of our [OIII] data. oxygen is exhibiting photoluminescence within the extremely rarefied plasma and UV winds being emitted by the new stellar cluster. This differs from the Ha and [SII], in that these latter emissions are originating from a thin, almost 2-D interface between a molecular cloud and the transparent media and associated incident UV light. Understanding this difference in emissions (either from the depths of ionic media, in the case of [OIII] or the surface of the molecular cloud in the cases of HII regions allows us to better visualize the 3D structure of the gas bodies. I personally have found it useful to think of Ha and [SII] as a phosphorescent coating or paint over the surface of a molecular cloud, that only glows when facing UV light.
Of course, other concepts and equations are necessary to describe the shape of our nebula, including how the gas bodies move. The astrophysical data, tells us that the movement of the gases follow the laws of gravity, inertia, thermodynamics and continuity, as you might think. Moreso, they tell us that, in most circumstances, we can also apply the equations of fluid mechanics (or magneto-hydrodynamics for ionic medium/plasma) that are described by the partial differential equations for compressible fluids that we refer to as the Navier-Stokes equations. This brings us full circle to G.G. Stokes again, ane one of his crowning achievements - in understanding fluid behavior both down here on earth and within space.
I will be using these concepts, including the N-S equation, and how they describe the Eagle Nebula as a hole in a molecular cloud created by stellar wind plasma, why the Pillars of Creation are a result of mobility instability, and why stellar nurseries form clusters, rather than singlets. Stay tuned to aprealspace.com for this upcoming posting.