Lagoon Nebula, M8

Burnham’s Celestial Handbook (forty years old and still available) describes M8 as “One of the finest of the diffuse nebulae….seen to consist of a fine irregular nebulosity enveloping the scattered open cluster NGC 6530”.

It goes on to say that “One of the remarkable features of the Lagoon Nebula is the presence of very tiny circular dark nebulae, known as globules, appearing as so many little black dots on the luminous background”.

These are now known as Bok Globules and they are believed be regions of gravitational collapse from whence new born stars will emerge. I’m not sure if I would describe them as circular but there are several Bok Globules visible on the above image.

The star cluster includes about fifty stars. The nebula is large, about three lunar diameters in apparent width, whilst the “lagoon” itself is the dark strip which is located just to the left of centre.

My previous attempt  at imaging this object, taken in 2017 with a DSLR camera, shows the nebula as a bluish-purple colour.

Object Details:

Designation: Messier 8, M8, NGC 6523 (nebula), NGC 6530 (cluster).
Constellation: Sagittarius.
Visual magnitude:  +6.0
Apparent size:  90′ x 40′
Diameter:  114 light years.
Distance:  4,300 light years.
Altitude during exposure:  42° above W horizon.

Please feel free to ignore the technical stuff:


Exposure:   240 x 30  sec = 120 min.
Gain: 260
Date:  2019-08-23
Location:  outer suburban.
Conditions:  clear.
Moon: No


Image acquisition:  SharpCap.
Method: Live stacked.
Darks: 10x
Image post-processing:  GIMP.
Cropping:   No
Sky:  0.63 e/pixel/sec.


Telescope: SkyWatcher Esprit  Type: 120ED triplet refractor
Focal: 840 mm F/7 Mount: SkyWatcher EQ6-R Pro
Camera: ZWO ASI 071 MC Pro
Type: CMOS 28.4mm 16 Mpx
Optical aids: Flattener: Y; filter: LP Guiding: No
Polar aligning: QHYCCD PoleMaster Polar Error: 01’ 09”

Geek Log:

[ZWO ASI071MC Pro]
Debayer Preview=On
Output Format=FITS files (*.fits)
Capture Area=4944×3284
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=40
Frame Rate Limit=1 every 4 seconds
Timestamp Frames=Off
White Bal (B)=50
White Bal (R)=53
Cooler Power=53
Target Temperature=-15
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000

Mono Bin=Off

Anti Dew Heater=Off
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=C:\Users\Roger\Desktop\SharpCap Captures\darks\ZWO ASI071MC Pro\RAW16@4944×3284\30.0s\gain_260\dark_10_frames_-14.8C_2019-08-23T11_25_55.fits
#Black Point
Display Black Point=0.14572864321608
#MidTone Point
Display MidTone Point=0.741206030150754
#White Point
Display White Point=1

Image © Roger Powell



    1. The randomness of the nebula is a contributor to its beauty and it can play tricks with the mind – but to me the overall shape reminds me of a flower, perhaps an orchid or a single foxglove.

      Thanks very much for your comment.


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