Messier 8 (Sagittarius)
Fig. 1 - Shining by the ionizing ultraviolet radiation of its embedded young stars: The emission and reflection nebula Messier 8 in Sagittarius, photographed with a 16-inch f/4.5 Dob on an equatorial platform.
| Object name: | Constellation: | Coordinates: | Apparent size: | Visual brightness: |
|---|---|---|---|---|
| Messier 8 (= NGC 6523) | Scutum | 18h04m / -24°23' | 90' x 40' | 4.6 mag |
The emission and reflection nebula Messier 8 ("Lagoon Nebula", NGC 6523, Sharpless 25, RCW 146, and Gum 72) in the constellation Sagittarius. Messier 8 is a large star-forming region and contains dark protostellar clouds, so-called globules. Within the nebula is the young open star cluster NGC 6530. Its stars were formed by material of the Lagoon Nebula and now ionize the surrounding gas.
The Lagoon Nebula is approximately 4,000-6,000 light-years from Earth, measures about 110 x 50 light-years and was discovered by Italian astronomer Giovanni Battista Hodierna in 1654 and independently re-discovered by English astronomer John Flamsteed in 1680 (source: Wikipedia).
Exposure time: 1h 9min (23x approx. 3min) at ISO 800, taken on July 13, 2018. Processing with Deep Sky Stacker and Photoshop. For this image, an Artesky 550 mm flat field generator was used for the first time to reduce vignetting caused by the camera and telescope. The flat field images drastically reduced the processing time. No further calibration frames were taken.
Unfortunately, the Lagoon Nebula was already low on the horizon and thin clouds reduced the sky transparency. Minutes after the last image, Messier 8 disappeared on the horizon.
Equipment: Canon EOS 450D Baader modified camera, TeleVue Universal Paracorr coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system.
Field of view comparison: image of the moon with the same setup.
Fig. 2 - Search chart for Messier 8. Copyright 2025 'The Mag-7 Star Atlas Project', www.siaris.net.