A Tail of Two Comets by Paul Robinson PanSTARRS and ISON
Comet PanSTARRS 2011-L4 Panoramic Survey Telescope And Rapid Response System Perihelion March 10, 2013: 0.30 AU from sun. Only about 3 weeks away!! May reach magnitude 1.5 March 9 th. Will be low in the evening sky in dim twilight slowly getting higher in following weeks as it fades. Will have nice dust tail curving to the left.
Comet PanSTARRS s orbit March 30 20 T=March 10 April 19 9 Feb 18 28 28 Feb March 10 20 18 30 April 9 19
Comet PanSTARRS orbit relative to the Earth and Sun to show tail orientation and viewing geometry 30 4 3 Jan Apr 5 Feb Mar 4 Earth Sun
Comet PanSTARRS in the evening sky Horizon, comet, stars and moon shown on March 12, 20 minutes before the end of twilight = 7:15 pm add 1 minute for each day after March 12 Ares Andr 10 o Peg Cetus 20 25 Horizon at end of twilight W 15 Moon Horizon 10 min before end of twilight Horizon 20 min before end of twilight NW 10 Horizon 30 min before end of twilight Horizon 40 min before end of twilight 7 Mars Sun
PanSTARRS magnitude performance as of mid January... Max mag 3.0
Other misbehaving comets: Hale-Bopp Note temporary lulls in brightening, as opposed to permanent changes. Brightening was able to resume at its previous rate.
Other misbehaving comets: Kohoutek Note longterm changes in brightening rate.
PanSTARRS magnitude performance Since... Max mag 1.7 Looks like fading period was temporary!
PanSTARRS current observations The pictures below are all about the same scale according to their source web site, and show a brightening, growing comet. The tail looks DUSTY. Jan 9 Jan 10 Jan 17 Feb 7
PanSTARRS current observations Feb. 13 from New Zealand Feb. 15 from Argentina
PanSTARRS current observations Feb. 17 from Australia
Comet ISON 2012-S1 International Scientific Optical Network Perihelion November 28, 2013: 0.013 AU from sun. May be as bright as magnitude -13 Nov. 28 th. Visible in morning sky; southeast before, and northeast after perihelion. May be visible in daylight on Nov. 28 th! May have very impressive, long tail after perihelion in December morning sky.
Comet ISON s orbit 19 29 Oct T=Nov 28.8 28 Nov 8 8 Nov 18 18 18 28 Dec 28 8 Dec 18 28 8 29 19 Oct
Comet ISON orbit relative to the Earth and Sun to show tail orientation and viewing geometry 1 Oct 2013 29 5 4 Jan 4, 2014 4 25 20 Nov Earth Dec 5 Sun
Comet ISON in the morning sky Comet, horizon & planets at 6:00 am Nov. 23 18 8 13 13 December 18 10 o 8 Mercury Saturn 23 November E 3 SE 28
Comet ISON in the day time Nov. 28 th, 2013 ** Be VERY CAREFUL viewing around the SUN!** 14 15 16 17 Sunset Times (red) are hour, MST with Positions valid for Boulder. Grid in degrees of azimuth and altitude relative to sun at each time. 13 12 Sun 11 10 9 Sunrise 8 7 Time Mag 7:00-9.0 8:00-9.6 9:00-10.4 10:00-11.3 11:00-12.3 12:00-13.0 13:00-12.7 14:00-11.8 15:00-10.8 16:00-10.0 17:00-9.3... Sunrise -5.0!
Comet ISON s magnitude performance so far...
Why should ISON behave??!! It s orbit strongly resembles that of the Great Comet of 1680 If part of that comet, it has been near the sun before. This implies that its current magnitude should be a good predictor of its future brightness
Latest Comet ISON photo Feb. 7 Mag 15.0 galaxy
Comet ISON s tail prediction based on performance of Comet Lovejoy in 2011 because of the stunning similarity of their observational geometry...
Comet ISON s tail prediction based on performance of Comet Lovejoy in 2011 1 Comet Lovejoy 2011 Oct 2013 29 5 4 Jan 4, 2014 4 Comet ISON 25 20 Nov Earth Dec 5 Sun
Tail length (deg) Comet ISON s tail prediction Comet Lovejoy s tail length in degrees -> AU by geometry Dt Len (AU) 10 0.31 15 0.63 20 1.03 25 1.52 Days after
Tail length (Au) Comet ISON s tail prediction Comet Lovejoy s tail length in AU -> ISON s length in deg by geometry Comet ISON tail estimates Dt Len (deg) Date. 10 30 Dec 9 15 65 Dec 14 20 81 Dec 19 25 75 Dec 24 Merry Christmas! Days after
A Tail of Two Comets by Paul Robinson Thank You!!