Asteroid (137108)1999 AN10 was discovered on January 13, 1999 by LINEAR and has become very popular since Andrea Milani and his coworkers have discovered that it is located within a mean motion resonance with the Earth and will undergo a series of close approaches with it, some of them yielding also a non-zero (though very small) impact probability (for details see the original paper by Milani, Chesley and Valsecchi and more recent updates). Precovery astrometric observations of the object on the plates of the Palomar Sky Survey dating back to 1955, identified and measured by A. Gnadig and A. Doppler (see MPEC 1999-N21) have allowed the computation of an improved orbit, excluding any possible impact with the Earth at least for the next 200 years (see our Minor Body Priority List). The images shown on the left were taken at Sormano Observatory on February 7, 1999, when the object was about 18 magnitude.

(153814) 2001 WN5 was discovered on November 20, 2001 at LONEOS. This object has a multioppositions orbit and a MOID of 0.0018 AU. It will reach the minimum geocentric distance from Earth of 0.00167 A.U. on June 26, 2028 ( see MBPL list ) such as 250000 Km +/- 5000 Km ( TECA list ).

A numerical integration of the orbit of asteroid (162004) 1991 VE has shown that it has repeated close approaches to Mercury, and therefore has stirred our interest about this object. During the favourable opposition (January 1999) the asteroid was included in the observing schedules of several observatories (including our own); a new computation, based on the improved orbit, confirms that 1991 VE has at least 11 encounters to Mercury (within 0.021 AU) during the next 200 years (see our list of planetary close encounters). Next approach (0.0106 AU) will happen on November 05, 2074, but a closer one seems to have occurred at the beginning of the past century (0.004 AU, on April 7, 1909).

In spring 1997 comet C/1996 J1 (Evans-Drinkwater) broken in two discrete components. This image, obtained on 1997 June 22, show the "double" comet a few months after the splitting. At that time component A (leftmost) and B had total magnitude 14.7 and 14.2 respectively.

Comet 1993e (Shoemaker-Levy 9) was first observed at Sormano in the night March 26/27, 1993. The bar-like aspect revealed to be composed by several nuclei (approximately twenty, having a size of the order of one kilometer) produced by the fragmentation of a greater celestial body a few months earlier.

Some principal condensations are visible in an enlarged CCD view taken with a focal lenght of 3 m, few minutes after the previous image. In July 1994 comet 1993e crashed on Jupiter atmosphere giving birth at one of the most celebrated events in the story of the observational astronomy.

Approaching its perihelion, comet C/1996 Q1 disgregated under the action of solar heat and gravity. At the time of this image, taken on Nov. 2, 1996, any attempt to obtain consistent astrometric positions was unsuccesful. Was comet nucleus still existent?

Events in dust tails

Cometary dust tails may shown internal structures. This was the case of the Great Comet of 1997 where the rare phenomenon called "striae" appeared during March, with its acme around days 16-20. This photograph was obtained at Sormano on March 20 using the 20 cm, f/5 astrograph. Exposure 20 min on TP4415 film.

The difference between asteroids and comets may be not always so clear. Minor planet 1979 OW7 at its second opposition displayed a filiform dust tail never seen before. This object is now redesignated as comet P/1996 N2 (Elst-Pizarro). The reasons for this unexpected unique feature remain obscure. This CCD image was obtained at Sormano on 1996 Aug. 22.

This unfiltered CCD image, obtained at Sormano on 2001 Nov. 19.962 UT, shows the elusive appearance of the anti-tail (pointed by the red arrow) of C/2000 WM1. The anti-tail of a comet is formed by the dusty component of the tail and may occur as a prospectical effect when the Earth crosses the comet orbital plane (for this comet it was predicted only five hours later). The dusty component of the tail, spread on the comet orbital plane as a fan behind the comet nucleus, when seen under particular geometrical conditions may appear on both sides respect to the comet central condensation.

This CCD image taken at Sormano Observatory on January 23, 2010, shows periodic comet P/2010 A2. The orbital elements of this comet discovered by LINEAR, are similar to a Main Belt Asteroid of the Flora family. Images taken by the Hubble Space telescope at the end of January 2010 has suggested that the cometary appearance could be the product of a collision between asteroids.

Other images of comets

An image of comet 153P/2002 C1 (Ikeya-Zhang) taken with the new 1024x1024 CCD of Sormano Observatory (March 20, 2002, 19:52 UT) with an exposure of 10 s. The object has been identified with comet C/1661 C1.

The effect of a Leonid fireball is clearly seen in this 2 min exposure photograph obtained by Sormano's team on Nov. 17, 1998 at 3:15 UT. The camera was equipped with a 50 mm lens, working at f/1.9 and a Fujiicolor 800 SuperPlus film.

The same morning at 3:30 UT some Leonids meteor trails were recorded in a new 2 min exposure time.

After two years from its launch and one high velocity flyby near the C type asteroid (253) Mathilde on June 27, 1997 the NEAR spacecraft, in January 1998, returned to its home planet briefly for a gravity assist enable to put it on a new path toward the minor planet (433) Eros. Only 12 hours before the minimum distance (about 3600 km above the Earth surface) the spacecraft was imaged at Sormano when still at 317000 km from our planet (a little less than the distance of the Moon!). This 240 second CCD frame, obtained on January 22, 1998 at 19:15:40 UTC (mid exp.) shows the 16 magnitude NEAR probe in rapid motion (16.4 arcsec/min) among faint stars in the costellation of the Taurus.

CCD image taken at Sormano Observatory on May 18, 2003 of the S-IVB third stage from the Saturn V rocket used to launch the Apollo 12 lunar landing mission in November 1969. In June 2003, J002E3 has departed from the Earth-Moon system.

The ESA's spacecraft Rosetta has its main scientific objective in the periodic Comet 67P Churyumov-Gerasimenko (for more details see the web page Spacecrafts to Asteroids and Comets). In order to reach its goal, the mission has been designed to perform a few fly-bies with the Earth.

Still at great distance from our planet, Rosetta was imaged on March 1, 2005 on four frames of 180 sec of exposure and combined in the animation at left (the estimate apparent magnitude was about 17).

On March 4, 2005 the European probe crossed the evening sky of Europe from South-East to West progressively increasing its speed. This trailed image of 30 sec of exposure has been taken on UTC 20:38:33 (start time) using the Sormano's 50 cm telescope plus 1Kx1K CCD camera and shows Rosetta near the 5.6 magnitude star 18 Leonis.

More than one hour later, on UTC 21:52:58 (start time), the spacecraft's motion has been computed in 247"/sec. Its trail was still visible in this 4 sec exposure image taken at 14° degree in altitude and three minutes before that Rosetta could disappear below the local western horizon (picture with the same scale that the previous one).

Image taken on March 31, 2001 from the Sormano Observatory at 21 UT. The event has been observed for about 1 hour.