Friday, October 5, 2012

Comet C/2012 S1 (ISON) - Update 2012, Oct. 4

We obtained further follow-up on C/2012 S1 (ISON) on 2012, Oct. 4.6, again  through the 2.0-m f/10.0 Ritchey-Chretien + CCD + Bessel R filter of Faulkes  Telescope North (F65) Haleakala.

Stacking of 9 exposures, 120 seconds each, produced an image where  a well developed and elongated coma measuring nearly 6"x9" is now visible, extended toward PA  280 deg. Click on the image below for a bigger version.

From this stacking, the Afrho parameter was determined to be about 1530  +/- 150 cm (see panel below). The total magnitude has been measured as R= 17.7. Click on the image below for a bigger version. 

For more info about comet C/2012 S1 (ISON) please see our previous post: 

by Nick Howes, Giovanni Sostero and Ernesto Guido


Anonymous said...

How big is ISON?

Anonymous said...


As C/2012 S1 ISON is approaching the "Jupiter Orbit" (I mean, the distance of Jupiter from the Sun...), is there something new concerning this comet ?

Are you able to confirm (or not...) that it could be a "great show" in November /December 2013 ?

Thank you for the coming updates !

Happy new year ! (the year of "The great comet of 2013" ?)

Team said...

Usually sizes of cometary nuclei are estimated when the comets are well away from the sun and there is no contamination by the coma.

Comet C/2012 S1 (ISON) is very active at present and so, due to the coma surrounding the nucleus, it is not possible to estimate its size.