ldjhandm Feb 18, 2013
--- In guide-user@yahoogroups.com, "ldjhandm" <lawrence@...> wrote:
>
> Thanks everyone for the replies. Next clear sky I will do not only longer but also staggered images for blinking. I would have done a guided image to go deeper but a 60-sec image is normally deep enough for mag 15 (and I had a minor hardware hiccup stopping me from guiding for that occasion).
>
> Query solved :-)
>
> Lawrence
>
> --- In guide-user@yahoogroups.com, Bill Gray <pluto@> wrote:
> >
> > On 02/16/2013 06:52 PM, jimborm@ wrote:
> > > I too agree with your coordinates, but I wonder if the comet is bright
> > > enough to show in a 60" image. GUIDE shows me that its magnitude should be
> > > about 15.2 (although I don't remember where I got my mag data from).
> >
> > Comet mags are bound to be somewhat iffy. They're usually based on an
> > effort to fit the entire observed arc, which may mean it'll fit well
> > in one place but not another, especially if outbursts are involved.
> > (If the comet suddenly brightens by six magnitudes, for example, you
> > can't really tweak one set of magnitude parameters to show both "before"
> > and "after" magnitudes correctly.)
> >
> > I went to the MPC Database Search at
> >
> > http://www.minorplanetcenter.net/db_search
> >
> > and in the first edit box, for "Data about an object", I entered ISON
> > and clicked on "Show". That got me several orbits, and further down,
> > it said there were 2078 observations available and that they were available
> > for download.
> >
> > Doing so and scrolling down to the bottom, I saw several dozen observations
> > made on 11 February, with magnitudes of 16.0 to 17.2. (With a few outliers
> > brighter or fainter than this.) So it would appear to be fainter than
> > predicted, at least right now.
> >
> > -- Bill
> >
>