5 THE ORBITS OF DISTANT OBJECTS SUCH AS KUIPER BELT OBJECTS (KBOS) AND CENTAURS ARE INHERENTLY UNCERTAIN BECAUSE EVEN THE BEST-OBSERVED OBJECTS HAVE ORBITAL ARCS THAT ARE SHORT COMPARED TO THEIR PERIODS. A TYPICAL KBO MAY ONLY HAVE A FEW YEAR OBSERVATA Other Administrative Action $0 4/15/22 Not listed THE ORBITS OF DISTANT OBJECTS SUCH AS KUIPER BELT OBJECTS (KBOS) AND CENTAURS ARE INHERENTLY UNCERTAIN BECAUSE EVEN THE BEST-OBSERVED OBJECTS HAVE ORBITAL ARCS THAT ARE SHORT COMPARED TO THEIR PERIODS. A TYPICAL KBO MAY ONLY HAVE A FEW YEAR OBSERVATA $0 4/15/22 Not listed THE ORBITS OF DISTANT OBJECTS SUCH AS KUIPER BELT OBJECTS (KBOS) AND CENTAURS ARE INHERENTLY UNCERTAIN BECAUSE EVEN THE BEST-OBSERVED OBJECTS HAVE ORBITAL ARCS THAT ARE SHORT COMPARED TO THEIR PERIODS. A TYPICAL KBO MAY ONLY HAVE A FEW YEAR OBSERVATIONAL ARC AND A 400-YEAR PERIOD. AS A RESULT UNTIL WE HAVE OBSERVED A DISTANT OBJECT THROUGH A FULL PERIOD ITS ORBITAL SOLUTION WILL ALWAYS BE AN APPROXIMATION AND THE EPHEMERIDES (RA/DEC) WHICH ARE DERIVED FROM THE ORBITAL SOLUTION WILL TEND TO DRIFT AWAY FROM "TRUTH" WITH TIME. THIS WILL EVEN HAPPEN FOR KBOS AND CENTAURS WHICH HAVE BEEN NUMBERED AND WHICH SUPPOSEDLY HAVE "WELL-DETERMINED" ORBITS. FOR EXAMPLE NUMBERED CENTAUR 63252 CURRENTLY HAS AN ERROR OF 9 ARCSEC AN ERROR WHICH WILL SLOWLY GROW WITH TIME. MANY OBJECTS HAVE ERRORS OF ONE OR MORE ARC MINUTES MOSTLY BECAUSE THEY HAVE RELATIVELY SHORT OBSERVATIONAL ARCS (PERHAPS A FEW YEARS) AND HAVE NOT BEEN OBSERVED AGAIN FOR SEVERAL YEARS. SOME RECENTLY-DISCOVERED OBJECTS HAVE VERY SHORT ARCS -- A MONTH OR LESS. IF NOT RECOVERED THE POSITIONAL ERRORS ON THESE OBJECTS WILL GROW VERY RAPIDLY SUCH THAT THEY WILL BECOME UNRECOVERABLE. ANY OF THESE DISTANT OBJECTS IF ASTROMETRICALLY OBSERVED TODAY WILL HAVE THEIR CURRENT POSITIONAL ERROR BECOME ZERO. THE ERROR WILL THEN GROW AGAIN WITH TIME BUT AT A SLOWER RATE BECAUSE THEY NOW HAVE AN IMPROVED ORBIT WITH A LONGER OBSERVATIONAL ARC. THE AIM OF THIS PROJECT IS TO TO OBTAIN ASTROMETRIC MEASURES FOR AS MANY OBJECTS AS POSSIBLE. WHY IS REDUCING THE POSITIONAL ERROR OF DISTANT OBJECTS IMPORTANT? SUCH OBJECTS ARE TYPICALLY QUITE FAINT. THIS MEANS THAT PHYSICAL OBSERVATIONS OF MOST OF THESE OBJECTS (COLORS SPECTRA LIGHT CURVES BINARITY) CAN ONLY BE OPTAINED ON LARGE GROUND-BASED OR SPACE TELESCOPES. TIME ON THESE TELESCOPES IS DIFFICULT TO OBTAIN AND IS VERY PRECIOUS. ONE DOES NOT WANT TO WASTE ANY OBSERVING TIME. BUT THESE TELESCOPES TYPICALLY HAVE SMALL FIELDS OF VIEW. WITHOUT AN ACCURATE POSITION THE OBSERVER DOES NOT KNOW WHICH OF MANY FAINT OBJECTS IN A FIELD IS THE DESIRED OBJECT. IF ONE HAS A TELESCOPE WITH A LARGE ENOUGH FIELD OF VIEW ONE CAN TAKE A SECOND EXPOSURE LATER IN THE NIGHT TO LOOK FOR THE MOVING OBJECT. THIS WILL IDENTIFY THE OBJECT BUT IS A WASTE OF AVAILABLE TIME. AND FOR TELESCOPES WITH SMALL FIELDS OF VIEW ESPECIALLY SPACE-BASED TELESCOPES OBJECTS WITH SIGNIFICANT ERRORS SIMPLY CAN'T BE OBSERVED AT ALL BECAUSE THEY CANNOT BE RELIABLY POSITIONED IN A SMALL APERTURE. THIS WORK WILL THUS KEEP A LARGER NUMBER OF DISTANT OBJECTS AVAILABLE FOR PHYSICAL STUDIES. ALSO GOOD ORBITS ARE REQUIRED IF WE ARE EVER GOING TO OBSERVE OCCULTATIONS OF KBOS EVEN IF WE USE A NETWORK OF TELESCOPES SUCH AS THE RECON NETWORK HEADED BY MARC BUIE AT SOUTHWEST RESEARCH INSTITUTE (HTTP://TNORECON.NET/). OCCULTATIONS ARE THE ONLY WAY WE HAVE OF DIRECTLY MEANSURING THE TRUE SIZES OF THESE OBJECTS FROM THE GROUND. I HAVE BEEN DOING THIS ASTROMETRY OF KBOS FOR MANY YEARS NOW UNDER SEVERAL NASA GRANTS. I ORIGINALLY USED THE LOWELL 1.8-M PERKINS TELESCOPE TO DO ASTROMETRIC FOLLOWUP OF BRIGHTER (R $0 3/3/21 4 THE ORBITS OF DISTANT OBJECTS SUCH AS KUIPER BELT OBJECTS (KBOS) AND CENTAURS ARE INHERENTLY UNCERTAIN BECAUSE EVEN THE BEST-OBSERVED OBJECTS HAVE ORBITAL ARCS THAT ARE SHORT COMPARED TO THEIR PERIODS. A TYPICAL KBO MAY ONLY HAVE A FEW YEAR OBSERVATIONAL ARC AND A 400-YEAR PERIOD. AS A RESULT, UNTIL WE HAVE OBSERVED A DISTANT OBJECT THROUGH A FULL PERIOD, ITS ORBITAL SOLUTION WILL ALWAYS BE AN APPROXIMATION AND THE EPHEMERIDES (RA/DEC) WHICH ARE DERIVED FROM THE ORBITAL SOLUTION WILL TEND TO DRIFT AWAY FROM "TRUTH" WITH TIME. THIS WILL EVEN HAPPEN FOR KBOS AND CENTAURS WHICH HAVE BEEN NUMBERED AND WHICH SUPPOSEDLY HAVE "WELL-DETERMINED" ORBITS. FOR EXAMPLE, NUMBERED CENTAUR 63252 CURRENTLY HAS AN ERROR OF 9 ARCSEC, AN ERROR WHICH WILL SLOWLY GROW WITH TIME. MANY OBJECTS HAVE ERRORS OF ONE OR MORE ARC MINUTES MOSTLY BECAUSE THEY HAVE RELATIVELY SHORT OBSERVATIONAL ARCS (PERHAPS A FEW YEARS) AND HAVE NOT BEEN OBSERVED AGAIN FOR SEVERAL YEARS. SOME RECENTLY-DISCOVERED OBJECTS HAVE VERY SHORT ARCS -- A MONTH OR LESS. IF NOT RECOVERED, THE POSITIONAL ERRORS ON THESE OBJECTS WILL GROW VERY RAPIDLY SUCH THAT THEY WILL BECOME UNRECOVERABLE. ANY OF THESE DISTANT OBJECTS, IF ASTROMETRICALLY OBSERVED TODAY, WILL HAVE THEIR CURRENT POSITIONAL ERROR BECOME ZERO. THE ERROR WILL THEN GROW AGAIN WITH TIME, BUT AT A SLOWER RATE BECAUSE THEY NOW HAVE AN IMPROVED ORBIT WITH A LONGER OBSERVATIONAL ARC. THE AIM OF THIS PROJECT IS TO TO OBTAIN ASTROMETRIC MEASURES FOR AS MANY OBJECTS AS POSSIBLE. WHY IS REDUCING THE POSITIONAL ERROR OF DISTANT OBJECTS IMPORTANT? SUCH OBJECTS ARE TYPICALLY QUITE FAINT. THIS MEANS THAT PHYSICAL OBSERVATIONS OF MOST OF THESE OBJECTS (COLORS, SPECTRA, LIGHT CURVES, BINARITY) CAN ONLY BE OPTAINED ON LARGE GROUND-BASED OR SPACE TELESCOPES. TIME ON THESE TELESCOPES IS DIFFICULT TO OBTAIN AND IS VERY PRECIOUS. ONE DOES NOT WANT TO WASTE ANY OBSERVING TIME. BUT THESE TELESCOPES TYPICALLY HAVE SMALL FIELDS OF VIEW. WITHOUT AN ACCURATE POSITION, THE OBSERVER DOES NOT KNOW WHICH OF MANY FAINT OBJECTS IN A FIELD IS THE DESIRED OBJECT. IF ONE HAS A TELESCOPE WITH A LARGE ENOUGH FIELD OF VIEW, ONE CAN TAKE A SECOND EXPOSURE LATER IN THE NIGHT TO LOOK FOR THE MOVING OBJECT. THIS WILL IDENTIFY THE OBJECT, BUT IS A WASTE OF AVAILABLE TIME. AND, FOR TELESCOPES WITH SMALL FIELDS OF VIEW, ESPECIALLY SPACE-BASED TELESCOPES, OBJECTS WITH SIGNIFICANT ERRORS SIMPLY CAN'T BE OBSERVED AT ALL BECAUSE THEY CANNOT BE RELIABLY POSITIONED IN A SMALL APERTURE. THIS WORK WILL THUS KEEP A LARGER NUMBER OF DISTANT OBJECTS AVAILABLE FOR PHYSICAL STUDIES. ALSO, GOOD ORBITS ARE REQUIRED IF WE ARE EVER GOING TO OBSERVE OCCULTATIONS OF KBOS, EVEN IF WE USE A NETWORK OF TELESCOPES SUCH AS THE RECON NETWORK HEADED BY MARC BUIE AT SOUTHWEST RESEARCH INSTITUTE (HTTP://TNORECON.NET/). OCCULTATIONS ARE THE ONLY WAY WE HAVE OF DIRECTLY MEANSURING THE TRUE SIZES OF THESE OBJECTS FROM THE GROUND. I HAVE BEEN DOING THIS ASTROMETRY OF KBOS FOR MANY YEARS NOW UNDER SEVERAL NASA GRANTS. I ORIGINALLY USED THE LOWELL 1.8-M PERKINS TELESCOPE TO DO ASTROMETRIC FOLLOWUP OF BRIGHTER (R Other Administrative Action $0 3/3/21 3 THE ORBITS OF DISTANT OBJECTS SUCH AS KUIPER BELT OBJECTS (KBOS) AND CENTAURS ARE INHERENTLY UNCERTAIN BECAUSE EVEN THE BEST-OBSERVED OBJECTS HAVE ORBITAL ARCS THAT ARE SHORT COMPARED TO THEIR PERIODS. A TYPICAL KBO MAY ONLY HAVE A FEW YEAR OBSERVATIONAL ARC AND A 400-YEAR PERIOD. AS A RESULT, UNTIL WE HAVE OBSERVED A DISTANT OBJECT THROUGH A FULL PERIOD, ITS ORBITAL SOLUTION WILL ALWAYS BE AN APPROXIMATION AND THE EPHEMERIDES (RA/DEC) WHICH ARE DERIVED FROM THE ORBITAL SOLUTION WILL TEND TO DRIFT AWAY FROM "TRUTH" WITH TIME. THIS WILL EVEN HAPPEN FOR KBOS AND CENTAURS WHICH HAVE BEEN NUMBERED AND WHICH SUPPOSEDLY HAVE "WELL-DETERMINED" ORBITS. FOR EXAMPLE, NUMBERED CENTAUR 63252 CURRENTLY HAS AN ERROR OF 9 ARCSEC, AN ERROR WHICH WILL SLOWLY GROW WITH TIME. MANY OBJECTS HAVE ERRORS OF ONE OR MORE ARC MINUTES MOSTLY BECAUSE THEY HAVE RELATIVELY SHORT OBSERVATIONAL ARCS (PERHAPS A FEW YEARS) AND HAVE NOT BEEN OBSERVED AGAIN FOR SEVERAL YEARS. SOME RECENTLY-DISCOVERED OBJECTS HAVE VERY SHORT ARCS -- A MONTH OR LESS. IF NOT RECOVERED, THE POSITIONAL ERRORS ON THESE OBJECTS WILL GROW VERY RAPIDLY SUCH THAT THEY WILL BECOME UNRECOVERABLE. ANY OF THESE DISTANT OBJECTS, IF ASTROMETRICALLY OBSERVED TODAY, WILL HAVE THEIR CURRENT POSITIONAL ERROR BECOME ZERO. THE ERROR WILL THEN GROW AGAIN WITH TIME, BUT AT A SLOWER RATE BECAUSE THEY NOW HAVE AN IMPROVED ORBIT WITH A LONGER OBSERVATIONAL ARC. THE AIM OF THIS PROJECT IS TO TO OBTAIN ASTROMETRIC MEASURES FOR AS MANY OBJECTS AS POSSIBLE. WHY IS REDUCING THE POSITIONAL ERROR OF DISTANT OBJECTS IMPORTANT? SUCH OBJECTS ARE TYPICALLY QUITE FAINT. THIS MEANS THAT PHYSICAL OBSERVATIONS OF MOST OF THESE OBJECTS (COLORS, SPECTRA, LIGHT CURVES, BINARITY) CAN ONLY BE OPTAINED ON LARGE GROUND-BASED OR SPACE TELESCOPES. TIME ON THESE TELESCOPES IS DIFFICULT TO OBTAIN AND IS VERY PRECIOUS. ONE DOES NOT WANT TO WASTE ANY OBSERVING TIME. BUT THESE TELESCOPES TYPICALLY HAVE SMALL FIELDS OF VIEW. WITHOUT AN ACCURATE POSITION, THE OBSERVER DOES NOT KNOW WHICH OF MANY FAINT OBJECTS IN A FIELD IS THE DESIRED OBJECT. IF ONE HAS A TELESCOPE WITH A LARGE ENOUGH FIELD OF VIEW, ONE CAN TAKE A SECOND EXPOSURE LATER IN THE NIGHT TO LOOK FOR THE MOVING OBJECT. THIS WILL IDENTIFY THE OBJECT, BUT IS A WASTE OF AVAILABLE TIME. AND, FOR TELESCOPES WITH SMALL FIELDS OF VIEW, ESPECIALLY SPACE-BASED TELESCOPES, OBJECTS WITH SIGNIFICANT ERRORS SIMPLY CAN'T BE OBSERVED AT ALL BECAUSE THEY CANNOT BE RELIABLY POSITIONED IN A SMALL APERTURE. THIS WORK WILL THUS KEEP A LARGER NUMBER OF DISTANT OBJECTS AVAILABLE FOR PHYSICAL STUDIES. ALSO, GOOD ORBITS ARE REQUIRED IF WE ARE EVER GOING TO OBSERVE OCCULTATIONS OF KBOS, EVEN IF WE USE A NETWORK OF TELESCOPES SUCH AS THE RECON NETWORK HEADED BY MARC BUIE AT SOUTHWEST RESEARCH INSTITUTE (HTTP://TNORECON.NET/). OCCULTATIONS ARE THE ONLY WAY WE HAVE OF DIRECTLY MEANSURING THE TRUE SIZES OF THESE OBJECTS FROM THE GROUND. I HAVE BEEN DOING THIS ASTROMETRY OF KBOS FOR MANY YEARS NOW UNDER SEVERAL NASA GRANTS. I ORIGINALLY USED THE LOWELL 1.8-M PERKINS TELESCOPE TO DO ASTROMETRIC FOLLOWUP OF BRIGHTER (R Funding Only Action $32.6k 7/1/20