M8 - Lagoon Nebula (NGC 6523)
The monochromatic image above shows M8 as shot through a Hydrogen Alpha filter.
Messier 8 or M8 (also designated NGC 6523) is a nebula and star cluster in the constellation Sagittarius. It has an apparent visual magnitude of 6 and its angular diameter is 90x40 arc-minutes. M8 lies at an estimated distance of 5200 light years. The Equinox 2000 coordinates are RA= 18h 03.8m, Dec= -24° 23´ which makes M8 best seen during the summer. The Messier Summer Star Chart shows the position of all Messier objects visible during that season. As one of the more famous objects in the Messier Catalog, it is commonly known as the Lagoon Nebula.
The Lagoon Nebula contains a number of interesting objects known as Bok globules, These are dark, collapsing clouds of protostellar material, many of which were catalogued by E. E. Barnard. A tornado-like structure is associated with one of the hot O-type stars due to the ultraviolet radiation it emits. The Hourglass Nebula is another unique structure that lies at the center of M8 where star formation is presently in progress.
In spite of its inclusion in the Messier Catalog, this diffuse nebula and star cluster were actually discovered by J. Flamsteed in 1680. According to Kharchenko et al. (2005), the distance of M8 is 4310 light years and its diameter is 9 light years. It contains over 130 stars and its estimated age is 2.3 million years.
For more information, see the Messier Catalog as well as specific entries for M8 in Wikipedia and SEDS.
Messier's Description of M8
May 23, 1764
`A cluster which appears in the shape of a nebula when observed with an
simple refractor of 3 feet; but with an excellent instrument one
perceives nothing but a large quantity of small [faint] stars; near this
cluster is a fairly bright star, surrounded by a very faint glow: this the
ninth star of Sagittarius, of seventh magnitude, according to
Flamsteed [9 Sgr]: this cluster appears in elongated shape, which extends
from North-East to South-West, between the arc of Sagittarius and the foot
of Ophiuchus.
(Diam. 30')'
Technical Details
- Object: M8
- Other Names: NGC 6523, Lagoon Nebula
- Object Type: nebula and star cluster
- Object Data: Apparent Magnitude = 6, Angular Size = 90x40 arc-minutes
- Object Position (Equinox 2000): RA= 18h 03.8m, Dec= -24° 23´, Constellation = Sagittarius
- Date: 2021 Jul 19-21 (3 nights)
- Location: Chile Remote Observatory, Observatorio El Sauce, Chile
- Partnership: Operated in partnership with David Churchill
- Telescope: Planewave CDK-17 (with Focal Reducer: f/4.5; FL = 1945mm)
- Camera: QHY 16200A with Integral 7-position Filter Wheel
- Mount: Astro-Physics 1600GTO
- Guider: Agena Starguide II / SBIG STi
- Sub-Exposures: Astronomik Filters
- H-Alpha (6nm): 120 x 10 min = 1200 min - Total Exposure: 20h 00m
- File Name: M08-CDK21Ha-C02w.jpg
- Field of View: 38.9' x 58.3' at 0.64 arc-sec/pixel
- Original Image Size: 3630 x 4540 pixels (16.5 MP); 12.1" x 15.1" @ 300 dpi
- Data Acquisition: David Churchill
- Image Processing: Fred Espenak
- Maxim DL: Image Calibration, Stacking, Log Stretch
- Adobe Camera Raw: Noise Reduction, Contrast Adjustments
- Photoshop CC: Curves, Levels, Hi Pass Filter
- Topaz Labs: Sharpen AI - Copyright: Fred Espenak
