I'm about 7 weeks into a distance learning MSc in astrophysics with LJMU. Over the past two weeks the topic being covered was the interstellar medium (ISM) - the vast regions filled with gas and dust between the stars throughout the Milky Way.
During this time the weather has been mostly awful! But there have been a couple of clear nights and during those I've finally been able to try a modified DSLR on loan from a friend to get some images nebulae that are beyond the reach of my normal DSLR.
Here are two pictures taken by stacking dozens of images together. Both were captured through an 80mm refractor.
These nebulae are created when radiation from a hot, young star ionises neutral hydrogen nearby. When the electrons recombine with the hydrogen a very particular photon (corresponding to red light) is emitted. If the star was surrounded by a uniformly dense hydrogen cloud then the resulting nebula would be spherical, with the boundary of the nebula being the place where ionisations and recombinations balance. That's nearly the case for NGC280 above! But hydrogen clouds aren't necessarily distributed so perfectly around stars. In the picture of NGC1499 the nebula is created by the bright star near the bottom of the picture. The hydrogen cloud is clearly some distance from the star.
Hydrogen exists in several forms throughout the Milky Way. Clouds of hydrogen atoms are called HI (H-one!) regions. These ionised nebulae are called HII regions (not to be confused with H2 regions of molecular hydrogen).
I always enjoy getting pictures of these fantastic objects but the astrophysics course is adding a new layer of appreciation to what I'm doing.
Dr Adrian Jannetta
Guitar strummin' explorer of the universe. Mild mannered maths teacher by day and astronomer by night.