First Light.
It is quite a dramatic image. Four hundred years ago a man stands in his workshop, grinding lenses. Using the skills of a ‘Cooper’ (a barrel maker), the old man constructs a tube from wooden slats. He fixes the lenses to the inside of the tube, and on a dark night holds the tube braced against a part of the roof and gazes up at the bright point of light. It is a planet, a ‘wanderer” so called from the ancient Greek planetai. This bright point of light is one of several of the points of light in the night sky that are not fixed in the sky like the stars. They ‘wander’ across the heavens in a path that can be tracked. The man gazes through the tube with its lenses which magnify the object viewed. He is astounded by the beauty of the bright point of light, Jupiter.
This is the “First Light” of the first telescope. It is how I imagine Galileo looking up at Jupiter and seeing its bands and discovering Jupiter has moons.
First light is a meaningful event for a telescope or any instrument that is used to view and study the objects above us and beyond us in the night – or daytime – sky. It is the proof that the telescope or other viewing instrument actually works. When I built a simple helioscope/projector using an inexpensive Newtonian telescope to view the Transit of Venus, my instrument had a “First Light”. It was exciting. I knew the telescope worked but had I constructed the screen perpendicular to the stream of light from the telescope to get a good image? Was the material I used for the projection strong enough to withstand handling and yet thin enough to allow the image of the sun to shine through.
Yes it was. I had achieved First Light.
First Light is the end point of making a telescope and the starting point of using it for observation. It is fully told in the story of the Hale Telescope in Richard Preston’s book First Light. In this book he tells about the construction of the Hale telescope and its use in discoveries in the cosmos.
And then this year we have First Light from the new James Webb Space Telescope that sits at a gravitational stable position known as Lagrange Point 2, approximately 1,000,000 miles from Earth.
The James Webb Space Telescope is not only robust, but it is also beautiful. In pictures of the Telescope before it was folded for launch the purity of lights and image seem to rise from its surface to greet the viewer.
What was James Webb Space Telescope’s Frist Light?
It can be seen in an image at the top of this article. This image is admired around the world for its clarity and stunning splendor. The image was published by NASA, ESA, CSA, and STSci (National Aeronautics and Space Administration, the European Space Agency, the Canadian Space Agency, and the Space Telescope Science Institute) with the caption, ‘The Webb telescope‘s image of the galaxy cluster SMACS 0723 includes thousands of galaxies, including the faintest objects ever observed in infrared. The light in the image is 4.6 billion years old.”
According to NASA, SMACS 0723 was chosen as one of the first five ‘targets’ for the James Webb Space Telescope, due to it being a “massive galaxy cluster” an image of which shows the foreground clusters which “magnify and distort light behind them. This creates a deep and detailed view into the extremely distant and faint galaxies beyond.”.
The image shows a cluster of galaxies with one in the upper center dominating. The other galaxies of the cluster are the other large white objects around the center of the picture. The mass of the galaxy, including the mass of its ‘dark matter,’ results in the numerous arcs of lensed galaxies as light from more distant galaxies behind the cluster is refracted and bent by the gravity of the near field cluster into the numerous arcs of light. Many are ‘mirrored’ and are seen as two lensed galaxies connected by a curved arc. These are not different galaxies. They are the single distant galaxy whose light is bent as it passes the galaxy cluster.
But where is the winged horse?
That comes from a separate target of the Webb telescope, Stephan’s Quintet. The Quintet is a compact galaxy group located in the constellation, Pegasus, the Winged Horse. Four of these galaxies are tied by gravity into each other. Each of these four galaxies spins on its own but is held close by the forces of the other four galaxies. In the distant future the four may merge into a single massive galaxy. The fifth galaxy of the Quintet is distant and has less of an effect on the others.
Stephan’s Quintet will be a target of my own star gazing after Pegasus rises to its best viewing position in the sky during the cool nights of October. It is perfect weather for star gazing, less moisture in the atmosphere bringing clear nights.
The image at top is taken from Webb’s First Deep Field (NIRCam Image) (webbtelescope.org)
The image at the bottom is taken from NASA – Stephan’s Quintet
Other sites for information on the James Webb Telescope and it’s First Light may be found at:
Where is NASA’s James Webb Telescope? (popularmechanics.com)
James Webb Space Telescope | NASA
NASA reveals targets of first James Webb telescope images – BGR