Orion’s constellation remains one of the most identifiable set of stars in the night sky, and right below the belt, resides Orion’s nebula, also known as Messier-42. We took several images of Messier-42 at 20 second exposures, using 5 different filters. Each filter corresponds to a specific wavelength on the spectrum of light, where filter 1 to 5 are blue, hydrogen-alpha, oxygen-3, Sulphur, and green, respectively.

We stacked the photos using the image editor Gimp, where we colourised the photos from each filter, and then stacked them again so they formed the final image. The photos corresponding to filter 1 and 5 were not included in the final stack.

Aadam’s edit

Alex’s Edit

Conor’s edit

Dhruv’s edit

Vlad’s edit

Ceinwen’s edit

Our photos can hardly compare to the startling images taken by the Hubble Space Telescope, the many drawbacks of imaging in central London. There are 3 main factors impacting the resolution of our images:

• Air pollution: the absorption and back-scattering of cosmic radiation, reducing the intensity of the received light
• Light pollution: artificial light from nearby buildings causes the night sky to take on a glow (due to scatter from molecules in the air), worsening contrast in images.
• Atmospheric Turbulence: differences in air pressure and temperature changes the refractive index of air, induces scintillation effects such as changes in visual position and fluctuations in brightness due to refraction. Makes the stars seem like they are “dancing” or “twinkling”

These atmospheric distortions are somewhat mitigated by prolonging the exposure and stacking of images to remove background.

Quick introduction to the project group of 2020! We are a team of third year (mostly) physicists consisting of Ceinwen, Dhruv, Aadam, Conor (formerly biochemistry!?), Alex and Vlad.

Alex, Conor, Dhruv and Malcolm spelling out LOVE with their hands and internally their hearts

Aadam enjoying the cold frigid January weather at midnight and definitely not thinking about his warm bed

Malcolm fixing our mistakes

Wild nights on the roof

Written by Ceinwen Cheng

11/02/2020