Typically, Emission Nebulae are composed of hydrogen, which glows in the characteristic red color of the Hα emission line at 656.3 nm. Occasionally present oxygen emits turquoise light at 500.7 nm.
The Sharpless catalog, which I use as a reference for representation, is an important resource for astrophotographers who enjoy photographing emission nebulae. It contains 312 HII regions, mainly located north of declination -27°.
Caldwell 31 – Flaming Star Nebula
Sharpless 229, also known as the Flaming Star Nebula, is a combination of reflection and emission nebula located in the constellation Auriga, approximately 1,500 light-years away from Earth. This nebula reaches its annual culmination at astronomical midnight around mid-December ...
Caldwell 49 – Rosette Nebula
The Rosette Nebula is a large emission nebula located in the constellation Monoceros, approximately 5,219 light-years away from Earth, reaching its annual culmination at astronomical midnight at the end of December ...
Messier 16 – Eagle Nebula
is a visually stunning emission nebula, located in the constellation Serpens, about 7,000 light-years from Earth. It includes the famous Pillars of Creation and reaches its annual culmination at astronomical midnight, making it best observed in late June ...
Messier 42 – Orion Nebula
The Orion Nebula is a bright diffuse nebula located in the constellation Orion, approximately 1,344 light-years away from Earth, and reaches its annual culmination at astronomical midnight mid December ...
Messier 43 – De Marian’s Nebula
Messier 43, located in the Orion constellation, is approximately 1,300 light-years away and reaches its annual culmination at astronomical midnight around mid-December ...
Sharpless 86
Sharpless 86 is a large emission nebula located in the constellation Vulpecula at a distance of about 6,000 light-years; it reaches its annual culmination at astronomical midnight in mid-July and is best observed during summer months ...
Sharpless 131 – Elephant’s Trunk Nebula
Sh2-131, also known as the Elephant's Trunk Nebula, is a dark globule and star-forming region located in the constellation Cepheus, approximately 2,400 light-years away from Earth, reaching its annual culmination at astronomical midnight and is best observed mid August ...
Sharpless 142 – Wizard Nebula
The Wizard Nebula is an emission nebula located in the constellation Cepheus, approximately 5545 light-years from Earth. It reaches its annual culmination at astronomical midnight in early September ...
Sharpless 147, Sh2-148, Sh2-149 // Sh2-152, Sh2-153
Sh2-147, Sh2-148 and Sh2-149 compact H II patches in Cepheus roughly 4,500 light-years away. Sh2-152 and Sh2-153: Two adjacent H II regions in Cassiopeia about 4,500 light-years away. Those are best observable in September ...
Sharpless 236 – Tadpole Nebula
Sharpless 236, also known as IC 410 or the Tadpole Nebula, is an emission nebula located in the constellation Auriga, approximately 2185 light-years away from Earth, reaching its annual culmination at astronomical midnight mid. December ...
Sharpless 252 – Monkey Head Nebula
The Monkey Head Nebula is an emission nebula located in the constellation Orion, approximately 3,200 light-years away from Earth, reaching its annual culmination at astronomical midnight at the end of December ...
Sharpless 277 – Flame Nebula
The Flame Nebula is a bright emission nebula located in the constellation Orion, approximately 900-1,500 light-years away from Earth. It reaches its annual culmination at astronomical midnight mid December ...
IC 5070 – Pelican Nebula
The Pelican Nebula, located in the constellation Cygnus, is approximately 1,800 light-years away from Earth and reaches its annual culmination at astronomical midnight early August ...
NGC 6914
NGC 6914 is a complex emission and reflection nebula located in the constellation Cygnus at approximately 6,000 light-years away; it reaches its annual culmination at astronomical midnight and is best observed during the summer months ...
LBN 728
LBN 728 is a nebula located in the constellation Ursa Major. It reaches its annual culmination at astronomical midnight and is best observed in mid-January ...
LBN 729
LBN 729 is an emission nebula located in the constellation Ursa Major. It reaches its annual culmination at astronomical midnight and is best observed in Mid-January ...