Comets C/2012 K5 (LINEAR) & C/2012 F6 (Lemmon)

C/2012 K5 (LINEAR) & C/2012 F6 (Lemmon) are the brightest comets currently visible in the sky (together with comet C/2011 L4 PanSTARRS which is unobservable in Northern Hemisphere until 2013 March while is observable very low in the sky in the Southern Hemisphere until mid February).

C/2012 K5 (LINEAR) was discovered by the LINEAR survey on CCD images taken with the 1.0-m f/2.15 reflector on May 25.3. For more info about the discovery of this comet see our previous post here. Latest visual estimates indicate a total visual brightness of about m1 ~ 8.5. This comet is very close to the Earth now (~0.369 AU, while it is at ~1.3 AU from the Sun). The visibility condition is good in the Northern Hemisphere. But after mid January, the comet moves away from the earth and fade out rapidly. It will become observable in good condition also in the Southern Hemisphere after January.

Below you can see a graph generated using the software Orbitas and showing the C/2012 K5 predicted magnitude (in red) versus the maximum height (for Northern Hemisphere). Click on the image for a bigger version.

C/2012 K5 (LINEAR)  - Faulkes Telescope South - January 07, 2013 (North is up, East to the left)

C/2012 K5 (LINEAR)  MCM (Median Coma Model) 

The MCM filter creates an artificial coma, based on the photometry of the original image, and subtract the original image itself in order to highlight the internal zones of different brightness that are very close to the inner core and that would normally be hidden from the diffuse glow of the comet.

C/2012 K5 (LINEAR)  RWM (Radial Weighted Model) 

RWM - 1/r theoretical coma subtraction.

Below you can see an animation of comet C/2012 K5 obtained using the same frames of the images above. Click on the thumbnail for a bigger version:

C/2012 F6 (Lemmon) was discovered by the Mount Lemmon Survey on CCD images taken with the 1.5-m reflector on March 23, 2012. Latest visual estimates indicate a total visual brightness of about m1 ~ 8.0. This comet is getting brighter much faster than expected. Perihelion is on March 24 at 0.73AU in 2013 March. If this trend continues it may brighten up to magnitude ~3. In the Northern Hemisphere, it is only observable until early January and then after middle May 2013 while in the Southern Hemisphere, it keeps observable while brightening gradually after this in good condition.

Below you can see a graph generated using the software Orbitas and showing the C/2012 F6 predicted magnitude (in red) versus the maximum height (for Northern Hemisphere). Click on the image for a bigger version. (Please consider that as explained above, the comet is surprisingly bright and over 4 magnitudes brighter than the ephemeris)

 C/2012 F6 (Lemmon) - Faulkes Telescope South - January 07, 2013 (North is up, East to the left)

C/2012 F6 (Lemmon) -  MCM (Median Coma Model)  

C/2012 F6 (Lemmon) - RWM (Radial Weighted Model)

Below you can see an animation of comet C/2012 F6 obtained using the same frames of the images above. Click on the thumbnail for a bigger version:

Images of  C/2012 K5 & C/2012 F6 taken in collaboration with the Faulkes Project and :

Longley Park Sixth Form College  - Ismail Musa
Glenlola Collegiate   -  Jacquie Milligan
Bury College   -  Dr. Lyshia Quinn

by Ernesto Guido, Nick Howes & Martino Nicolini