It’s definitely worth your time to click through this link and see the hover annotations, and then click to view the 5574 x 4824 pixel full-res image to just scroll around. Find the Horsehead nebula just below the belt.
Regarding the Lambda Orionis region at top middle: this was the focus of my PhD thesis so I can add a few details. Lambda itself (not often called by it’s Arabic name, Meissa — https://en.wikipedia.org/wiki/Meissa) is a blue O star among ten B stars illuminating a relatively hollow bubble. On the left and right sides of this red bubble, you might see two brighter edges of red which are the B35 and B30 clouds respectively where some new stars are still forming today.
Here’s my theory about how this bubble evolved over the last 10 million years, including a supernova about 1Myr ago:
http://www.astro.wisc.edu/~dolan/thesis/Dolan-thesis.pdf#page=132
(note that p124 schematic is rotated about 45 degrees from the Volskiy color picture due to Earth sky coordinates vs Milky Way galactic coordinates)
Originally shared by Astronomy Picture of the Day (APoD)
A 212-Hour Exposure of Orion
Image Credit & Copyright: Stanislav Volskiy, Rollover Annotation: Judy Schmidt
http://apod.nasa.gov/apod/ap151123.html
The constellation of Orion is much more than three stars in a row. It is a direction in space that is rich with impressive nebulas. To better appreciate this well-known swath of sky, an extremely long exposure was taken over many clear nights in 2013 and 2014. After 212 hours of camera time and an additional year of processing, the featured 1400-exposure collage spanning over 40 times the angular diameter of the Moon emerged. Of the many interesting details that have become visible, one that particularly draws the eye is Barnard’s Loop, the bright red circular filament arcing down from the middle. The Rosette Nebula is not the giant red nebula near the top of the image — that is a larger but lesser known nebula known as Lambda Orionis. The Rosette Nebula is visible, though: it is the red and white nebula on the upper left. The bright orange star just above the frame center is Betelgeuse, while the bright blue star on the lower right is Rigel. Other famous nebulas visible include the Witch Head Nebula, the Flame Nebula, the Fox Fur Nebula, and, if you know just where to look, the comparatively small Horsehead Nebula. About those famous three stars that cross the belt of Orion the Hunter — in this busy frame they can be hard to locate, but a discerning eye will find them just below and to the right of the image center.