2010 RF12 animation 2010 SEP 07 - 0648-0823
- 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".
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.
- 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.
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.
> 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.
- 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.
> Is your software available to Patrick? The commonly available programs dontIn theory, sure. In practice, it's really tedious to populate the
> really handle long trails all that well.
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!"
- Gordon Garradd wrote:
> Is your software available to Patrick? The commonly available programsA while back, I figured out what ought to be a very feasible way to
> don't really handle long trails all that well.
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: