[AZ-Observing] 2002 NY40 tracking
- From: Brian Skiff <Brian.Skiff@xxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Fri, 16 Aug 2002 11:34:22 -0700 (MST)
The close flyby of 2002 NY40 will be happening over the next 36-48 hours.
You can get ephermerides and charts from a number of sites, as indicated
below, which are lines grabbed from recent posts to the Minor Planet Mailing
List. The sites should all have current elements and at a current osculating
epoch. The Lowell orbit-integration scheme adjusts the time-step of the
perturbations to quite small intervals for such a close approach. This
business is necessary because of the strong perturbations caused by Earth
and the Moon, which are accounted for separately in these calculations.
These ephemeris sites will also want to know an MPC observatory code, for
which anything in the western US is sufficiently accurate for this. This part
is necessary because the asteroid will be roughly the Moon's distance, and
the parallax of the Moon from one place on Earth to another is large enough
to make a difference (think of grazing lunar occultations, where 100 meters
is enough to make a difference between occultation/no occultation). Previously
I suggested using sites such as 695 (Kitt Peak) for southern Arizona and
688 (Lowell-Anderson Mesa) for northern Arizona. The Sky & Telescope
lists (shown below) have just three or four sites in the western hemisphere,
which gives you an idea of how critical this particular item is---necessary but
not super-critical.
The current ephemeris uncertainty for Saturday night at dusk (which is
the prime viewing time for Arizona) is now only about 30 arcsec, so there
should be no problem in finding it for that reason. The motion at that time
will be nearly 7 arcminutes per time-minute (!), so it will quickly move
along the track and out of a telescope field. For instance, if your ephemeris
time is for 10 clock-minutes earlier/later than when you are actually looking,
the asteroid will have moved 1.2 degrees away.
The asteroid should be about mag. 10.0 on Saturday evening. On Sunday
evening it will have faded to mag. 25, so this viewing opportunity is very
short-lived.
\Brian
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JPL NEO site: http://neo.jpl.nasa.gov/cgi-bin/db?name=2002+NY40
NEODys site:
http://newton.dm.unipi.it/cgi-bin/neodys/neoibo?objects:2002NY40;main
The Minor Planet Center's Minor Planet Ephemerides service at
http://cfa-www.harvard.edu/iau/MPEph/MPEph.html
will also produce elements and an ephemeris for near your location
by specifying an MPC code number.
For an ephemeris: http://asteroid.lowell.edu/cgi-bin/koehn/asteph
For a finder chart: http://asteroid.lowell.edu/cgi-bin/koehn/astfinder
Also you may review this general interest article which shows a
non-precision star chart (probably not accurate enough to point a telescope
and locate the object, however).
http://science.nasa.gov/headlines/y2002/30jul_ny40.htm
Sky & Tel (from Roger Sinnott):
We have prepared four detailed finder charts for 2002 NY40,
showing its path across a 60-degree arc of sky on Saturday night,
August 17-18. These charts are PDFs, meaning they can be viewed
or printed on a computer that has Acrobat Reader (free downloadable
software).
For links to the charts, see our updated article on the flyby at:
http://skyandtelescope.com/observing/objects/asteroids/article_697_1.asp
The links to the charts are on page 2.
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