Narrowband

Abell 39: A planetary nebula and the most perfect sphere in the night sky

Discover the mesmerizing beauty of Abell 39, a planetary nebula renowned for its stunning spherical shape. While many nebulae are complex and chaotic, Abell 39 stands out as a rare gem in the night sky. This article delves into the fascinating evolution of stars, from their fiery beginnings as main sequence stars to their transformation into white dwarfs and the breathtaking nebulae they leave behind. Join us on a journey through the cosmos, exploring the intricate processes that create these celestial wonders and the vital role they play in the universe’s grand tapestry.

The Anatomy of a Stellar Nursery

Introducing the Rosette Nebula / Stellar Nursery When I first started to image stellar nurseries, I really didn’t know anything about them. I was told that stars are being born there – that is pretty awesome, but I was curious what was it about these light generating molecular clouds (MCs) that made them prolific star builders. Sure, stars are also created in turbulent dark molecular clouds, but stellar nurseries really churn out the stars at a much higher level – often creating whole open clusters of stars. Many of the stellar nurseries get very large and can even be mapped from their Halpha light signal in other galaxies. Ok, so my interest was piqued – I had to figure out

Its Supersonic! – But it’s complicated

The massive explosion of a supernova sends material (and light) outwards in all direction, at velocities greater than the speed of sound. The speed of sound is another way of saying the speed that pressure or density waves can travel or disperse through the medium that it is moving through. The particles ejected by the supernova are moving so fast and so much momentum that they don’t disperse but act like a moving wall of material, bulldozing and sweeping up any additional material in its path. Along the way, the particles that make up this moving wall, or shock front involves a lot of friction between particles so that it heats up to extreme temperature (million of degrees) and the wall emits light that we see as the remnants or remains of a supernova.
This wall, known as a shock-front, eventually runs out of momentum due to is expanding spherical geometry and sharing of momentum, but remains visible to our cameras long afterwards, until it fades through cooling. The patterns of emitted light are both beautiful and distinctive from other subsonic flow patterns, and these patterns enable us to identify these objects as supernova remnants. or leftovers from the supernova explosion.

Narrowband Light & Filters – A Quick Overview

Using the fascinating and recently discovered Squid Nebula (Ou4) as an example, I discuss the use of narrowband filters to image emission nebula. To emit light at specific narrowbands, the right element, degree of stimulation (UV light), and even density must be present. It makes for beautiful images and reveals a lot of structure in the targets.