Lagoon and Trifid in hydrogen sea

These two clouds of interstellar matter are placed probably in the most prominent area of Milky Way in the constellation of Sagittarius. Under dark sky Lagoon can be seen with naked eye as faint patch of light. Trifid requires some some optical aid – like binoculars. Despite their low apparent altitude in the sky both nebulae has ben classified by Charles Messier in his catalogue. Lagoon is called M8, and Trifid is M20. At my home location this sky area is moving at low altitude, so imaging it is somehow possible, but requires clear view to southern horizon. I already made an attempt to this area two years ago in Tuscany, but my observing location was not perfect. This summer I collected photons at Tenerife. Weather was not perfect, but I managed to shot few pictures. First one below is Lagoon and Trifid nebulae area imaged in hydrogen alpha band – both nebulae literally float in the hydrogen sea.

Lagoon is classified as an emission nebula and HII region. It is really huge cloud – it is estimated to has real dimensions 110×50 light years. Contains several Bok globules – that are dark, collapsing clouds of protostellar material. Some of them have been catalogued by E.E. Barnard (B88, B89 and B296 – see annotated image lower).

M8 Lagoon
M8 and M20 nebulae area in hydrogen alpha band

Large version

Trifid is smaller. Both nebulae are located more less at the same distance from Earth, to their apparent size corresponds to their real dimensions. Trifid nebula is a combination of many objects: emission nebula, open star cluster, dark nebula (dark patches are designated Barnard 85) and reflection nebula (not visible here in hydrogen alpha band).

M8 and M20 nebulae close up
M8 and M20 nebulae close up

Large version

Image technical data:

Date: 1-3 August 2019
Location: Tenerife, North
Telescope: Samyang 135/2 @ f/2.8
Corrector: none
Camera: QHY163M, gain 100
Mount: iOptron SmartEQ Pro
Guiding: 50mm guidescope + ASI290MM
Exposure: H alpha 50x120 seconds
Conditions: transparency good, Moon
Image with annotated objects

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