The Taos Astronomer / Hands-On Observing Sessions and Instruction

Image obtained 8-21/22-2015 through RVO's Megrez 80mm refractor with Orion field-flattener lens, using a Baader-modified Canon XSi DSLR and BackyardEOS image-acquisition software -- 16 selected and stacked 240-second luminance frames combined with multiple dark, flat and bias calibration frames shot at ISO 1600 and totaling more than 160 minutes (64 minutes effective luminance) were used to create this image; optics driven by the Losmandy G-11 mount equipped with Ovision's precision RA worm gear, guided with an Orion SSG3 Monochrome CCD camera using Maxim DL Pro and post-processed with DeepSkyStacker and Photoshop CS3.

"The Lagoon and Trifid Nebulae are a pair of bright emission nebulae in the constellation Sagittarius. The Lagoon Nebula (M8) is an H II region or interstellar cloud that glows red due to ionized hydrogen as it recombines with lost electrons. The nebula's distance is estimated at 5000 light years which would make its physical diameter about 100 light years. The Lagoon is an active stellar nursery and contains a number of dark globules (collapsing clouds of protostellar material). From Earth, the apparent size of the Lagoon is 40 by 90 arc-minutes and it shines at apparent magnitude +6.0. The Trifid Nebula (M20) consists of a conspicuous emission nebula as well as a remarkable reflection nebula. The emission nebula glows red in the characteristic color of ionized hydrogen while the reflection nebula is blue from nearby hot, young stars. The Trifid Nebula gets its name from its three-lobed appearance. The distance of the nebula is estimated at 5000 light years but there are large uncertainties in this value. The apparent size of the Trifid is 28 arc-minutes and its apparent magnitude is +6.3." -- from Fred Espanek's AstroPixels site

Image of M20 and M21 for location/identification/description here. Above, it's to the right of M20 (Trifid Nebula), deeply imbedded in the Milky Way, beginning right on the edge of the image (oops!), description from Fred Espanek's AstroPixels site