Loading ...
Sorry, an error occurred while loading the content.
 

2010 RF12 animation 2010 SEP 07 - 0648-0823

Expand Messages
  • Patrick Wiggins
    I tried to do astrometry on 2010 RF12 tonight but as I suspected it was moving too fast for me to measure. Rather than throw out the images I strung them
    Message 1 of 6 , Sep 7, 2010
      I tried to do astrometry on 2010 RF12 tonight but as I suspected it was moving too fast for me to measure.

      Rather than throw out the images I strung them together into an animation.

      20 one minute exposures shot at 5 minute intervals this morning (7 September) between 0648-0823 UTC.

      Distance at that time was about 0.0048 AU.

      North is up, east to the left. FOV is about 18' x 26'. Image scale 2.163".

      http://users.wirelessbeehive.com/~paw/temp/2010RF12.GIF

      It's a bit tough to see. It moves from upper left to lower right.

      Should anyone care to try measuring any of the images just let me know and I'll either email them or put them online for download.

      patrick
      718
    • Gordon Garradd
      Hi Patrick, those exposures/trails are far too long to measure properly, you need to shorten the exposure to keep the trail length around the same size as your
      Message 2 of 6 , Sep 7, 2010
        Hi Patrick, those exposures/trails are far too long to measure properly, you
        need to shorten the exposure to keep the trail length around the same size as
        your seeing. IE, if you are working in ~4" seeing, you could expose for 15 sec
        when it was moving at 16"/minute (as it was a few hours ago here) and get decent
        astrometry. The intensity of the images will still be similar to what it is on
        the images you posted, only they wont be trailed.

        You need to make sure the time is correct though! Accurate shutter timing to
        0.1sec is required for these very fast movers once they get up to and above that
        rate of motion, and there is provision in the reporting format for 6 decimal
        places in time.

        cheers, Gordon


        Patrick Wiggins wrote:
        > I tried to do astrometry on 2010 RF12 tonight but as I suspected it was
        > moving too fast for me to measure.
      • Dave Tholen
        ... As long as both ends of the trail are visible, it can be measured properly. We do that all the time. Our April 5 measurement of 2010 CN141 had reference
        Message 3 of 6 , Sep 7, 2010
          > Hi Patrick, those exposures/trails are far too long to measure properly,

          As long as both ends of the trail are visible, it can be measured
          properly. We do that all the time. Our April 5 measurement of
          2010 CN141 had reference star trails over 70 pixels long.
        • Gordon Garradd
          Is your software available to Patrick? The commonly available programs dont really handle long trails all that well.
          Message 4 of 6 , Sep 8, 2010
            Is your software available to Patrick? The commonly available programs dont
            really handle long trails all that well.

            Dave Tholen wrote:
            >
            >
            > > Hi Patrick, those exposures/trails are far too long to measure properly,
            >
            > As long as both ends of the trail are visible, it can be measured
            > properly. We do that all the time. Our April 5 measurement of
            > 2010 CN141 had reference star trails over 70 pixels long.
          • David Tholen
            ... In theory, sure. In practice, it s really tedious to populate the data file manually. To populate it automatically requires the program that precedes it
            Message 5 of 6 , Sep 20, 2010
              > Is your software available to Patrick? The commonly available programs dont
              > really handle long trails all that well.

              In theory, sure. In practice, it's really tedious to populate the
              data file manually. To populate it automatically requires the
              program that precedes it in the processing pipeline. Backing up
              to the beginning of the pipeline is a program that has been
              customized for the particular cameras that we use, and it also
              requires a local copy of the USNO-B1.0 catalog. And none of the
              programs have a level of documentation intended for outside use.
              So, as the saying goes "Easier said than done!"
            • Bill J Gray
              ... A while back, I figured out what ought to be a very feasible way to handle trailed objects. I didn t put it into my Charon astrometry software, because
              Message 6 of 6 , Sep 22, 2010
                Gordon Garradd wrote:

                > Is your software available to Patrick? The commonly available programs
                > don't really handle long trails all that well.

                A while back, I figured out what ought to be a very feasible way to
                handle trailed objects. I didn't put it into my Charon astrometry
                software, because by that point, it already looked as if PinPoint,
                Canopus, Astrometrica, etc. were doing a better job of things than
                Charon did anyway.

                Still, the basic algorithm may (I think) be of interest to some
                of the people still writing astrometry/photometry software:

                http://www.projectpluto.com/trailed.htm

                -- Bill
              Your message has been successfully submitted and would be delivered to recipients shortly.