Celestial hemisphere:  Southern  ·  Constellation: Sagittarius (Sgr)  ·  Contains:  Hourglass nebula  ·  Lagoon nebula  ·  M 8  ·  NGC 6523  ·  NGC 6526  ·  NGC 6530  ·  The star 7Sgr  ·  The star 9Sgr
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Lagoon Nebula - M8, Bruce Rohrlach
Lagoon Nebula - M8
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Lagoon Nebula - M8

Getting plate-solving status, please wait...
Lagoon Nebula - M8, Bruce Rohrlach
Lagoon Nebula - M8
Powered byPixInsight

Lagoon Nebula - M8

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Description

The Lagoon Nebula - If heaven has a portal it might look like this.

It has been almost 5 months since I last imaged a DSO (Deep Sky Object; as opposed to nearby planets) and consequently not much went right last night (or so I thought). Besides being rusty and slow with getting everything together, for the life of me I couldn’t get PHD2 to guide my scope. After guiding for a few seconds it would start bleeping and stars would track beyond the range of the mount correcting pulses. So with some disappointment I started imaging the Lagoon Nebula (M8) with consecutive 30 second unguided exposures instead of my planned 5 minute exposures. The polar alignment of my telescope mount was also dodgy due to Sigma Octans (Polaris Australis) being behind a gum tree (which by the way has poor prognosis for a long life span). So I wasn’t expecting much from last nights imaging session, with just 45 minutes worth of Hydrogen Alpha (Ha) filter data (90 x 30 second exposures) and 45 minutes worth of Oxygen 3 (OIII) filter data (90 x 30 second exposures). But I was pleasantly surprised to see how the stacked data came out once processed in Astro Pixel Processor. I guess that's the benefit of bright DSO's, poor conditions can still yield stunning imagery.

Ha data here is mapped to Red and Green; OIII data is mapped to the Blue channel. Red-Green mixtures produce Yellow, so the outer parts of this nebula are rich in hydrogen gas, whilst the central parts (bluer-tinge in this false colour composite) are rich in oxygen gas. These enormous roiling interstellar gas clouds (110 x 50 Light Years in dimension) in the Carina-Sagittarius arm of the Milky Way are collapsing under gravity and are a nursery spawning many hundreds of stars that are condensing out of the cloud. An open star cluster can be seen here (NGC 6530) in the centre-left, where gases have collapsed sufficiently to ignite their own nuclear furnaces (suns). The gas cloud is being illuminated from within by ultraviolet radiation from supergiant stars which ionise the surrounding gas clouds.

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Lagoon Nebula - M8, Bruce Rohrlach