Manually guided, 30 sec exposure in Nebulosity 4 with QHY6 camera, Sky Watcher 80mm Equinox Pro on manual alt-az Manfrotto mount.
Before anyone asks, I could not find the Ring Nebula tonight in the guide eyepiece on the CCDSPEC!
From RIchard Walk’s book, “Spectral Atlas for Amateur Astronomers”, Vega is a Lamba Bootis Class star. Stars of this class are classified according to their H-Balmer lines approx. on main sequence within spectral types F0-A0. Striking here is a generally weak metal-line spectrum with the main feature of Mg II absorption at 4481 A (448.1nm). This line is shown well on my spectra of Vega below as are the H-Balmer lines.
The following is from Wikipedia (https://en.wikipedia.org/wiki/Balmer_series):
The Balmer series is characterized by the electron transitioning from n ≥ 3 to n = 2, where n refers to the radial quantum number or principal quantum number of the electron. The transitions are named sequentially by Greek letter: n = 3 to n = 2 is called H-α, 4 to 2 is H-β, 5 to 2 is H-γ, and 6 to 2 is H-δ. As the first spectral lines associated with this series are located in the visible part of the electromagnetic spectrum, these lines are historically referred to as “H-alpha”, “H-beta”, “H-gamma” and so on, where H is the element hydrogen.
Transition of n 3→2 4→2 5→2 6→2 7→2 8→2 9→2 ∞→2 Name H-α / Ba-α H-β / Ba-β H-γ / Ba-γ H-δ / Ba-δ H-ε / Ba-ε H-ζ / Ba-ζ H-η / Ba-η Balmer break Wavelength (nm) 656.45377 486.13615 434.0462 410.174 397.0072 388.9049 383.5384 364.6 Energy difference (eV) 1.89 2.55 2.86 3.03 3.13 3.19 3.23 3.40 Color Red Aqua Blue Violet (Ultraviolet) (Ultraviolet) (Ultraviolet) (Ultraviolet)
The familiar red H-alpha spectral line of the Balmer series of atomic hydrogen, which is the transition from the shell n = 3 to the shell n = 2, is one of the conspicuous colours of the universe. It contributes a bright red line to the spectra of emission or ionisation nebula, like the Orion Nebula, which are often H II regions found in star forming regions. In true-colour pictures, these nebula have a distinctly pink colour from the combination of visible Balmer lines that hydrogen emits.