On april 19th, asteroid 2014 JO25 was at its closest to earth (1.9 million km, almost five times farther than the moon). This 650m-wide rock belongs the categories of NEO (Near Earth Objects): it will probably impact earth one day because its orbit crosses earth’s orbit. But be reassured, this is a probabilistic calculation made for the billion years ahead. It has zero chance to pay us a visit within the next century.
It was an ideal case for testing Unistellar’s prototype, a 4.5″ telescope equipped with Enhanced Vision. At 11pm local time in Marseille (France), the asteroid was crossing Canes Venatici towards Coma Berenices. The asteroid was easily identified in the eyepiece: it was brighter than the surrounding stars (magnitude 10.7) and its movement was obvious. For someone used to seeing fixed stars in the eyepiece, it was quite puzzling to see a moving object.
The images acquired during that night were then used to test Unistellar’s field recognition algorithm. All stars in the field of view could be identified (see image below where magnitudes are indicated) and more interesting, the position of the asteroid could be determined with 1 arcsec precision (1/3600th of degree): on Apr. 19th at 21h24m18s UT its coordinates were RA 13h29min39s, DEC 38°54’28″. It was moving with an apparent speed of 2.8 arcsec/s which corresponds to approximately 30 km/s in space. This data will be sent to the Minor Planet Center of the International Astronomical Union. It will feed the orbit computation and thus lead to more precise predictions.
The next meeting with a NEO is forecast in 2027: the 800m-wide asteroid 1999 AN10 will fly by at a distance of 380,000 km (1 earth-moon distance). But it is highly probable that another one will be discovered before (JO25 was discovered in 2014, 3 years ago), maybe thanks to Enhanced Vision TelescopeTM users!