Click here for full resolution image
Messier 8, the Lagoon Nebula, is immersed in a large HII emission region. This wide field image (3×3 degrees) captures the three large nebulae that are visually very close (I call this region the “Sagittarius Bouquet”). Messier 8 spans more than one degree of arc and lies about 4,300 light years away. Messier 20, bottom, left of center, has a larger distance from us, 5,200 light years. IC 4685, usually disregarded due to its much more famous neighbors, lies about 4,000 light years away from us. To get a higher resolution, this wide field image has been combined with high resolution images of the three nebulae, taken separately with a 20 inch telescope in three consecutive years. The image has been taken with narrowband filters (mapped for natural color, Ha (Red and Blue), SII (Red) and OIII (Green and Blue), broadband Blue to catch the reflection nebulae in M20 and IC4685. Shorter exposure times were taken for the stars in RGB. Here you can find the high resolution images of M8, M20 and IC4685, used for this wide field image.
This image has been selected as APOD (Astronomy Picture Of the Day) on July 27th, 2017.
Additional Information
Object
Name(s): Messier 8, Messier 20 and IC 4685
Type: Emission/Reflection/Dark Nebulae
RA: 18h 05m 10s
Dec: -23º 52’ 53”
Constellation: Sagittarius
Size (arcmin): 90×40, 30×27 and 30×25 respectively
Magnitude: +6.0, +6.3, +10.0 resp.
Distance: All around 4,500 ly
Image
Date: Wide field: June 2017; High Resolution 2015 and 2016.
Location: iTelescope.net, SSO near Coonabarabran, NSW Australia
Size: 2.7×2.6 degrees
Telescope: TOA 130mm f/5.7 and Planewave CDK 20” f/6.8
Camera: SBIG STX16803 (4096x4096pix) in both cases
Guiding: Astrodon MonsterMOAG off-axis guider
Total exposure: 44.5 hours (Wide field: Ha: 2h; OIII 2h; SII: 1h40m) (High Resolution: a total of 37 hours Narrowband, used only as Luminance) (Stars wide field: RGB: 54 min) (Broadband Blue 1 hour).
Processing: CCDStack, Photoshop CC 2017