Messier 20 (original) (raw)

This image shows the Trifid Nebula M20, a cloud of gas surrounding a star-forming region. It is a 3-color composite of 3 black-and-white photographic plates taken with the 3.9-meter Anglo Australian Telescope and different emulsions and filters, exposed as follows: Blue 35 minutes on Kodak IIa-O with GG 385 filter, Green 30 minutes on IIa-D/GG 495, Red 30 minutes on 098-04/OG 610. Its components, an ionized red emission nebula 40 light-yeras in diameter, and a blue reflection nebula are nicely visible, together with an appealing system of conspicuous dark nebulae, obscuring the light from regions behind them.