This week’s image was taken on the evening of Jan. 5 during a remarkably clear night when the winter Milky Way shone brilliantly over my rural Georgia observatory. The “California Nebula,” as it is called due to its resemblance to the shape of the Golden State, is an emission nebula glowing within the constellation of Perseus.
This celestial object is a very faint target for anyone trying to find it with the telescope. However, it is perfect for wide-field astrophotography. I used my RASA 8 telescope with its attached ASI294 camera to capture the image. Photons of light from this interstellar cloud of dust and gas were gathered over a period of two hours by stacking a series of two-minute exposures.
As a coincidence, the nebula happens to pass at its zenith (the point in the sky straight overhead) for observers in central California. This occurs because its declination (north-south celestial coordinates) generally matches the terrestrial latitude of California. In any case, the nebula covers an area of sky more than 2.5 degrees across, which is about five times the width of the moon. In reality, the California nebula extends over an expansive 100 light years of space, and it is more than 1000 light years away from Earth.
The associated star map shows the precise position of the nebula in the night sky. Its host constellation of Perseus was mapped by ancient Greek skywatchers as their mythological hero who slew the gorgon Medusa. Found in the right knee area of the constellation figure, the dark mottled clouds of the California Nebula may one day spawn new stars, planets, and just possibly life!