Comet Lovejoy (C/2014 Q2) graced our skies in January 2015 as its closest approach to Earth during its 8000 year orbital period. Its bright green head was just visible to the naked eye for observers at dark sites, although its tail was very dim. It’s the 5th comet found by Queensland Astronomy, Trevor Lovejoy. The set of images that were combined to produce this image were taken on the evening of the 11/1/15, just before moon rise.
To capture the comets head and tail was challenging. Typically, astrophotography centres around capturing images on a mount that tracks the stars so that the images are free of star trails. In most cases multiple exposures are taken and then stacked together to reduce noise and increase signal. This results in a much cleaner image than if just one photo was taken. The trouble with a comet is that is moving through the star field and will become very blurred over long or multiple exposures.
To get around this problem I processed the images in two sets. The first stacked the stars as usual, the second stacked the comet and then I added them back together using Pixinsight so that the comet was in the position of the first image. I am really happy with the result and its fitting it was the first I captured with my 8 year old son. He proudly now has the print on his bedroom wall.
When I processed the image there appeared to be two spiral galaxies. They look like elongated stars on either side of the tail about 1/3 down its length from the top right hand corner. Sky X software confirms that they are the galaxies PGC14076 and PGC14088! The bright star is 31 Tauri (the 31st bright star of Taurus), which is about the limit you could just make out with your naked eye in an average light polluted outer suburb. Looking at how many other stars there are in the picture makes you really wonder how big space is. Even more so when you see the two galaxies, probably 100,000 light years wide like our Milky Way appearing as a few millimeters on a photo! I wonder how many years ago the light that was captured left those galaxies!
Total exposure time 90 minutes.
3 minute exposures in Red Green Blue
Captured using The SkyX software
Takahashi FSQ106ED refractor. FL520mm at f5
Starlight Express Trius H694 cooled CCD, filter wheel and Lodestar guider.
Software Bisque Paramount MX+ Robotic Mount
Pxinsight, Adobe Lightroom 5. Topaz Denoise.