Thursday, January 05, 2012
Comet C/2009 P1 Garradd - January 4, 2012
Comet C/2009 P1 Garrad taken with the iTelescope T14 instrument in Mayhill New Mexico. I took 5 x 90 second images, each panel is a separate treatment of the images. Top Left: Images stretched individually in FITS Liberator with Arcsin x(Arcsin x) and autobalance. Stretched images then stacked on the comet using ImageJ, and the stack Summed using Z project. After that I did a square root process to clean up the background a bit. Top Right: Images stretched individually in FITS Liberator with Arcsin x(Arcsin x) and autobalance. Stretched images then stacked on the stars using ImageJ, and the stack Summed using Z project. After that I did a square root process to clean up the background a bit. Bottom Left: Raw Images stacked on the stars using ImageJ, and the stack Summed using Z project. After that I did a square root process. Click on any image to embiggen.
The comet looks very impressive now, the right tail is the dust tail, and the top tail is the ion tail (the bottom image is inverted). The comet is now in part of its orbit where the tails are very widely separated. The images were spoiled a little by the advent of twilight, as the comet gets higher in the morning sky it should look better. Australians have to wait a couple of moths before it appears in our sky again.
Roland Ligustri's shot about the same time using the T20 colour instrument is here. For some earlier images of Garradd, see here (scroll down a lot).
Labels: astrophotography, comet, comets, iTelescope