Rho Ophiuchi (left center blue) and Antares (bottom right yellow) and their associated nebulae are striking star forming regions in the Milky Way.  This field shows an abundance of what I find amazing cosmic wonders.

In the distance are globular clusters, brighter M4 at about 7000 light years and NGC 6144 at about 33,000 light years (the entire Milky Way galaxy is somewhat larger than 100,000 light years).  

Dark molecular clouds extend from roughly our position towards Rho Oph and Antares.  Near the center we see where new stars are emerging from the clouds in which they were formed.

Rho Ophiuchi at about 350 light years distant was formed from within the clouds and is now sculpting the remaining gas with stellar winds and photon pressure.  The bright blue light of the stars is reflected back to us by the gas that also preferentially scatters shorter wavelengths.

The red supergiant star Antares illuminates its nebula from behind at a distance of about 550 light years.  Antares is near the end of its life and expected to go supernova within the next 10,000 years.  When it does explode it will be at least as bright as the full moon, easily visible in broad daylight.  Antares is unstable pulsing in size by perhaps 30%.  On average Antares' diameter is larger than the orbit of Mars around our Sun and is some 10,000 times brighter than our Sun in visible light. 

 The mostly red light from Antares is scattered by the gas between it and us and seen more yellow to us with the bluer wavelength being preferentially scattered.

Another mechanism for nebula to glow is shown by red Sharpless 9 just above the blue star Alniyat near the top of the image.  In this case high energy photons from Alniyat blast electrons from hydrogen atoms and when re-captured descend through energy states, one of which emits the pretty red light of Hydrogen Alpha.

This is a simple RGB stack of 22 exposures each of 10 minutes, no reassigning of colors here though I did reduce the stars somewhat.  Borg107FL F/3.9 refractor, ASI6200MM Pro, Baader RGB filters.  Though, I think, a pretty good image, there are still halos around the stars due to the Baader filters that thanks to Stephen Garretson I hope to fix next trip to Dark Sky New Mexico.  Also, I will work on back focus to get it within the 200 micron tolerance to correct the elongated stars in the corners.