Finding M42

M42: The Great Orion Nebula

Catalogues
M42 (and M43); NGC 1976
Names
The Great Orion Nebula
Type
Emission Nebula: Star Forming Region
and Multiple Star Systems
Constellation
Orion
Season Visible in Evening
Winter
Conversation Notes
Easiest nebula to find and see – even binoculars. Makes a good contrast at a star party, show M42 (star birth) and a planetary nebula (star death).

M42 is an emission nebula – a vast cloud of hydrogen gas, which is glowing red in response to the radiation it is absorbing from the bright stars it contains. The cloud of gas is still giving birth to new stars at it condenses under its own gravity.

This famous object doesn’t really require finding instructions – it is so easy to find that you need only know where it is. I include the instructions here to be found by newcomers to the hobby, or to be linked to in response to questions.

Finding M42

M42 is an easy to find component of the constellation Orion. Find Orion, “the Hunter”, in the South during winter. Easy to find by his conspicuous 3-star “belt” between his shoulders and feet.

Find Orion’s “belt” of 3 stars.
Find Orion’s “sword”: 3 slightly dimmer stars hanging from his belt.
Centre the centre star of the belt in your telescope and enjoy the view.

This is a typical view of M42 at 60x. This simulation shows what I typically see through a 235 mm (9.25)” SCT under light-polluted city skies, or a 100 mm (4″) refractor in very dark skies.

Look for 4 bright stars in the centre of the cloud, in a close-spaced square. This is called ”the Trapezium”. It is a multiple star system of more than 4 stars, but only 4 are visible in small telescopes. They were recently born from the cloud of gas.

 


Aren’t nebulae supposed to be swirls of amazing colours? Not when viewed with your eyes – here is an explanation.


All the above images were generated with Starry Night Pro.



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