M27
MPC OSERVATORY 643
Astronomical Research
Dedicated to expanding human knowledge
Saturn
TRACKING ELUSIVE HERMES
Hermes
This image shows Hermes streaking across the sky on November 1, 2003.  Only 7.8 million km from Earth at the time, it was moving at 1523 arcseconds per hour!  During this 60-second exposure, it zipped across almost 14 pixels in our image,  and passed across our entire field of view every 45 minutes.
LOST AND FOUND
The minor planet Hermes has eluded astronomers since its close pass by Earth in 1937.  Astronomers knew that it had passed uncomfortably close to Earth, but just after it passed by its unlit side was available.  It faded from magnitude 8 to magnitude 21, dimming by a factor of 60,000 times, in a couple of days.  After being tracked for only 5 days, with a scant 16 sightings, of which 7 are now known to be inaccurate, the object was lost in the sun's glare.  Its orbit could not possibly be determined from that information.

For 66 years it remained the "loose cannon" of minor planet research - a potentially hazardous asteroid that was following an unknown course through space and occasionally approaching Earth.

Its recovery on October 15, 2003, made instant headlines in the astronomical community, and around the world.  When a bright, fast-moving object was spotted that evening, it was almost immediately identified as Hermes.  Within days it had received extensive coverage, with optical and radar telescopes, and had been linked to objects in pre-discovery photographs from 2001, 2002 and 2003.  It is now numbered (69230).

With its orbit now very precisely known, it provides an excellent case study in the choatic orbits of objects that pass so close to planets. Hermes frequently passes very close to Venus, Earth, Mars, and Vesta.  Its orbit is frequently reshaped by these encounters, requiring intensive computer work to determine its course. 

It was found that Hermes passed only 741,000 km from Earth on October 30, 1937.  It passed even closer (without being spotted) on April 26, 1942, at only 634,000 km.  This is just about as close as it can get in its current orbital path.  Between 1937 and 2003, it made a total of 8 close passes (< 9 million km) to either Venus or Earth.  It passed 7,157,000 km from Earth on November 4, 2003, and was last seen on November 7, 2003.
Movie
This animation, taken November 1, 2003, shows how quickly Hermes moved in just 5 minutes.  It can be seen just up and right from center.  Assembled from 4 exposures, clear filter, 30-seconds exposure time each.