M42 – The Great Orion Nebula – Hydrogen Alpha Mono
My first astro-image of the new decade, and my first from the garden of my new house after a recent move. This is my first take on M42, the Great Orion Nebula for a number of years, as in the past 5 years or so, capturing this has been nigh-on impossible from home due to there being trees and other obstacles in the south. The new place is far better suited for Southern sky shenanigans, and so finally I’m able to grab this beauty again. This is a capture in the Hydrogen Alpha emission band, so currently appears as mono. I’ll be adding the OIII emission to this when I get another clear night to grab them. This will turn it into a colour image.
This is one of the most astounding objects in the night sky. It’s bright enough to see easily in binoculars – take a look at the central star in Orion’s ‘sword’, and if your eyes are good, you can see in a darkish sky that it’s slightly ‘fuzzier’ than the rest. Look through binos and it’ll start to become apparent that something is going on there. The bright part of the nebula is the area of the central star in the sword.
Although this is bright, it’s still not possible to see it in quite this amount of glory visually, though thorough gradually larger and larger scopes, it reveals itself more and more, and a fair bit of this whispy nebulosity becomes visible, especially when you allow your eyes to adjust and spend some time exploring the area through the eyepiece. Even small scopes will show this object well, and it’s something that also benefits from using an OIII filter to observe – you get a different take on its lovely whispiness through one of those.
As for what it is apart from rather pretty? It’s a stellar nursery. It’s a big cloud of gas (mostly hydrogen) and dust where stars are being born. The stars at it’s centre are relatively young, hot stars, about 300,000 years old (yes that’s young in stellar terms!).
As a gloriously bright object relatively speaking, it presents its own challenges in that the core is far, far brighter than the surrounding areas. This means that to capture all the detail in the core whilst at the same time getting the whispy stuff in and around, shorter exposures of the core are needed, which are then processed separately, then combined back in to get the full dynamic range.