Re: [Phys-L] Comet ISON

["Anthony Lapinski" <Anthony_Lapinski@pds.org>]

A friend just sent me this. It shows the location of ISON against the
background stars -- just below the Big Dipper.

[
http://media.skyandtelescope.com/documents/Comets_Ison_Lovejoy_LateNov.pdf
]http://media.skyandtelescope.com/documents/Comets_Ison_Lovejoy_LateNov.pdf



Phys-L@Phys-L.org writes:
> Yes, I agree that the geometry doesn't sound correct at first glance. 
> But the question to ask may be whether the comet will be in a section of
> the sky which, like Polaris, is visible both before and after sunset.  It
> need only be far enough north of the sun to be seen.
>
> Paul
>
>
> On Nov 14, 2013, at 8:44 PM, Bruce Sherwood <Bruce_Sherwood@ncsu.edu>
> wrote:
>
> > Of course many objects including Polaris are visible before sunrise and
> after sunset on the same day, but we're talking about an object (the
> comet ISON) which is very near the Sun during these weeks and will (as
> far as I can determine) never be visible at both times on the same day.
> It's important not to tell people who want to try to see this comet that
> they can go look for it after sunset.
> > Bruce
> >
> >
> > On Thu, Nov 14, 2013 at 3:49 PM, Paul Nord <paul.nord@valpo.edu> wrote:
> > Consider only that the North Star is in the sky ALL the time.  For
> someone in the northern hemisphere, it never sets.  That should help to
> explain how something may be seen both before and after sunset.
> > Here at about 40º N, there is a big chunk of the sky around the pole
> star which is always above the horizon.  Around that circle I can draw
> other circles which are in the sky "most" of the time and only set
> briefly at some point every 24 hours.  Some parts of the sky are above
> the horizon for 12 hours.  And some parts of the sky (e.g. southern
> constellations) never rise above the horizon.
> > Paul
> >
> >
> > On Nov 14, 2013, at 4:03 PM, Bruce Sherwood <Bruce_Sherwood@ncsu.edu>
> wrote:
> > > Good point, but judging from the images shown in Sky & Telescope, as
> ISON
> > > approaches the Sun it's near Mercury and Saturn in the sky, a bit
> below but
> > > near the ecliptic plane, so not visible after sunset. Then, something
> I'd
> > > missed in the article, the closest approach to the Sun is about Nov.
> 28, so
> > > close that it may disintegrate due to extreme heating and tidal
> effects. If
> > > it does emerge, the images shown for the first few days in December
> show it
> > > moving nearly vertical, so definitely not visible after sunset.
> > >
> > > Bruce
>
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