November Object of the Month: The Pelican
Each month I chose one of my images and give you some background to what it is and how it was photographed. This month it is The Pelican Nebula.
The Pelican Nebula
About the Pelican
The Pelican is a huge expanse of ionized gases, plasma and dust 1,800 light years away from the Earth. (One light year is the distance travelled by light in a vacuum in one year, 5.88 trillion miles. The Pelican is 1,800 x 5.88 trillion miles away. The Pelican is in the direction of the constellation Cygnus the Swan which rides high in the Northern hemisphere sky during the summer months.
The Pelican is what is known as an emission nebula and is a prominent star forming region, so stars are being born.
The Birth of a Star
In the close-up you can see a white plume at the tip of this enormous column. For a short period stars that are forming send out a strong magnetic force through their poles and when this hits the interstellar medium it shows up as this plume. This is known as a Herbig-Haro object.
Imaging The Pelican
This object is extremely faint from Earth and not much light is reaching the telescope and camera. In addition it emits light at specific wavelengths associated with certain ionized states of gases.
I use specialist filters which capture certain emissions from these gases, in this case Hydrogen Alpha (Ha), Oxygen III (OIII) and Sulphur II (SII). Using my telescope and cameras I captured 23 hours of data through these three filters over many nights. Each exposure was 20 minutes and at the end of each night I discard the sub optimal images, such as when the seeing conditions were not perfect or a satellite crossed the field of view. In fact I discard around 30% of all data, meaning I required a lot more imaging to get to the 23 hours of good data. Over time I build up the data for each filter and eventually have enough to start the long process of calibration and processing.
In addition to the ‘light frames’ of data I also require calibration frames. These are additional types of photographs which are designed to remove electronic noise and artefacts from the long exposure images. Once all these have been secured they can be combined using software with the light frames to give clean data to work with.
During this process I want to extract the beautiful detail that exists buried within the raw data and at the same time make it look stunning for the Galaxy on Glass range. I use a convention to assign the colours developed for the Hubble Space telescope. This means that I assign the SII to the red channel, Ha to the green and OIII to the blue channel. Using this convention shows rich blues and golds and the wispy details of the nebulosity.
Can you see why it is called The Pelican? No I can't really either!
I hope this gives you some insight into the beauty of this dramatic object. If you are interested in having this as a piece of wall art- either Framed Backlit, Frameless Acrylic or as a Fine art Print, then simply pop along to The Pelican in the Shop and you can purchase a limited edition piece right there.
A 32" Framed Backlit Pelican
An extra large Frameless Acrylic Pelican
If you would like to see all the options available for The Pelican click here