Asteroid Hazard Research
Overview of the NEO Problem
Since the realization that Asteroids and Comets pose a hazard to planet Earth a number of observatories under the guidance of the International Astronomical Union
(I.A.U.) Minor Planet Commission have been hunting for new objects that come near the Earth,
collectively called, NEO's, (Near Earth Objects)
or specifically when referring to Asteroids, NEA's (Near Earth Asteroids). Current thinking is that if an Asteroid is detected to be capable of hitting the earth many years or even decades from now, then we can do something about it. Like, for
example, rendezvous with the "killer" asteroid
and change it's course. Perhaps, if it is of economic value, like a pure Nickel Iron, or spent comet, composition
then we might guide the offending object to the moon for future mining to recover the monies spent on moving it and then some.
For extensive additional informational resources please see the section below entitled,
"NEO Information" NEO
Research Objective
The research objective at the observatory is to find and track Asteroids and occasional
Comets. The hunting of targets, known and unknown, is done by taking several images with our Charge Coupled Device Cameras
(C.C.D.). The C.C.D. digital cameras are cooled electronically to about 50 degrees below ambient temperature to increase
sensitivity to the dim images we are hunting. Via our software we can align multiple images with common stars and then rapidly flash all images in sequence. This latter process is known as
"blinking" and the stars in the flashing matched images will not move but any object in the solar system will be seen jumping between it's
changing positions. This blinking technique helps us identify Asteroids in the star field we are taking images of.
As a general rule, the closer the Asteroid to the Earth, then the brighter is it's image.
Also, the greater the "jump" in the blinking process, since it's angular motion
would be faster when near us. Targets are obtained from a
variety of sources. If you are interested in the details of how to hunt
and track Asteroids see the section below "Resources for Asteroid
Hunters"!
NEO Research Measurements
Once the target is identified our software permits us to calculate the positions of every object on an image. We use the celestial coordinates,
Right Ascension
(RA) and Declination (Dec) to pin-point target position. Once we have a proper scale for the image, we can measure the position
of the object to within one second of arc accuracy. As a general rule, we are about
90 % on target accuracy of less than 1 sec of arc. Inherent in these measurements is the fact that our
computer clocks are updated via the Naval Observatory Clocks every five
minutes so that our images are time stamped and our measurements are accurate
to within one second of time. These precise readings are collected into a report that is sent to the IAU's Minor Planet Center
located at Harvard. The positional data (the whole process is called Astrometry )is used to help calculate or update the orbital parameters that determine the orbit about the Sun. Hence, we
help keep accurate track of these potentially dangerous objects that can create extreme environmental disruptions of the biosphere by colliding with our planet.
For details on the use of the data see the section below"
Resources for Asteroid Hunters." NEO Information
The overall problem and the
some of the latest information is provided by Ron
Baalke, Near-Earth Object Webmaster NASA's Near Earth Object
Program Office Pasadena, California
This site is a definitive site for the entire field with extensive links to
the world wide effort., including NASA, ESA and observatory efforts
dedicated to the problem. Check the site out at Near
Earth Objects For
example: Lots of overall Details at this site at
link: Near Earth Object Introduction
etc.
Resources for Asteroid
Hunters
Note:
this is a web linked resource:
The
Basic idea:
Overall coordination of the world wide effort is found at the IAU
Minor Planet Center. This center establishes the guidelines for
undertaking Astrometry known as the Guide
to Minor Body Astrometry. Here you will find resources on Astrometry
software and techniques, as well as , how to report your findings. We
currently are using products from "Software
Bisque". The combination of "CCDsoft" to run our
Cameras and "The Sky" to control our computerized Meade
16" GPS LX 200 Telescope has given us a very user friendly systems
so that Undergraduate students can join Our Research Group
and assists us in this effort. We also use Astrometrica
which is excellent for blinking, finding asteroids and its "track and
stack" is worth learning because it will increase your ability to get
faster and dimming targets!
Essentially, you need a telescope, a CCD camera, computer and serious
dedication to this undertaking. A computerized telescope and being on the
web is recommended. Additional
Software Resources: Time
Keeping software: We have been using
the "Tardis" time synchronization software in our Windows based
computers very successfully. "Tardis" can be found at many sites
on the web. Use a search engine, such as, "www.google.com"
to locate and install the software. Obtaining
Targets to Track: Once you establish yourself as
a official IAU observatory (see the Guide
to Minor Body Astrometry) you will need targets to track. The
secret of a good nights run is to plan ahead. There are a number of targets
that are needed and you should look over the following places to obtain
targets. As a general rule, our list below gives ordered priority to
the MPC NEO confirmation targets, the MPC's monthly critical list,
then either the European NeoDys priority targets as well as the Lowell
Observatory targets. If you join the recommend Minor Planet Mailing List
(see below) you will be able to be informed as to what is happening
currently, as well as, occasionally, get other interesting targets to
track. 1. MPC
NEO Confirmation page Once you select an object a predicted
position (an ephemeride) of the target per hour on a given day can be
generated for your observatory. 2. Orbital
Elements: MPC Critical-List Minor Planets this link is for obtaining the
elements in the form to load into popular planetarium-type software
packages. For example: we use the "Sky" and it and other
software permits you to directly load the above within the software if you
are connected to the web. Hence, you have access to know where the
targets are via your software to help plan your evenings run. 3. Check out
the "Priority List" first and Menu of Opportunities last at the European
Centered Space Guard System via the site the MPC can be used to generate
an ephemerides of the targets. 4. Obtain targets from monthly
"Critical lists" from the Lowell
Observatories Asteroid Services 5. Lots of bright targets are located
at FUAP (followup astrometric
Program site). Do
I have a new Discovery?: When
tracking known objects you will find that many times, depending on the field
of view of your system, additional targets show up in blinking. Hence, it is
important to know what other asteroids are in the area of your image.
Your software should be able to plot all known asteroids in either the
"MPC's "MPCORB" Data base or the Lowell
observatory's ASTORB data base of all known Asteroids. Minor
Planet Mailing List : We strongly advise joining the Minor
Planet Mailing List. This link has additional valuable web resources to
study. Evaluating
your Results: The
European NEODys site
keeps track of all NEA's, as well as, all
observatories doing the work and specific information on the quality of
measurements. For example, Statistics
on all Asteroids measured at the IAU 294-Astrophysical Observatory at
the College of Staten Island. The details of every optical
NEA measured at IAU #294 is invaluable for us to know how effective are
the various techniques we are using. The MPC also keeps general statistics
on observatories and how well they are doing approaching the suggested
accuracy of positions to less than one second of arc at The
MPC Residual page. Improvement is always possible when
residuals( sort of errors) get large!
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