Most of the minor planets and asteroids are in the Minor Planet Centre Orbit Database (MPCORB) which is downloadable via my planetarium package, Cartes du Ciel. The chart can then be configred to display the positions of the objects. However, you might want to add an object which isn't in MPCORB, such as a nearth-earth object. Follow this link to find how.

(131699) Eris 

Not a particularly pretty picture, but that's because I've stretched the image to its limits in order to reveal the faint dwarf planet Eris which glows very dimly at magnitude 18.7.

Eris - formal designation (136199) Eris - was only discovered on January 5th 2005 from images taken in 2003. It is the largest dwarf planet, some 27% more massive than Pluto, and is therefore the 9th largest body orbiting the Sun.

It lies above the much brighter star (mag 10.92!) GSC 4687-2132 in the constellation of Cetus.

These 'discovery' images (lower one is simply the top one inverted) are actually from a combination of six 5-minute exposures, but Eris is barely visible above the background noise which is clearly visible across the image. In fact I would not be at all confident that the speck was Eris were it not for comparison with other images taken a few days either side and a cross reference with where Cartes du Ciel says Eris lies. Whilst the comparison chart doesn't have enough faint stars to make it obvious, it did allow me to identify roughly where to look on the image on the 3 dates I originally imaged Eris.

At the time I wasn't 100% sure that this was Eris, but was very confident nonetheless that I had indeed imaged the 19th magnitude dwarf planet.

A few weeks later on a cold clear late December evening I was able to get a longer 'look' at Eris. Over 75 minutes of imaging allowed me to boost the S/N ratio for Eris to around 7, enough for me to be 100% confident this time.

Thr bright star to the lower left of Eris is mag 10.92 GSC 4687-2132. The two stars which look like a ":" colon to the lower left of Eris are mag 15.08 GSC 4687-1542 (top) and mag 14.81 GSC 4687-1841.

9 Metis

Here is a short sequence showing 9 Metis nudging northwards across the southerly regions of Aries on 17th December 2008. There are 3 frames in the sequence, 10 minutes apart, each frame comprising a 60 second exposure. The motion isn't spectacular - I worked out that its motion would be about 2' in 10 hours, so you may struggle to detect 4-5" of drift in the elapsed 20 minutes of this sequence. 

9 Metis (the '9' denoting that Metis was the 9th asteroid discovered) is 366km along its longest axis, and is currently 1.35au from the Earth. Now some 6 weeks after opposition, its magnitude is around 9.6, still reasonably bright.   9 Metis was discovered in Ireland by Andrew Graham on April 25th 1848.

NEO 2008 EV5

On 23rd December 2008 the asteroid 2008 EV5 passed within 8.4 lunar distances of the earth. Its size (thought to be around 400m based on radar observations) and its orbit has led to it being designated a potentially hazardous object by the Minor Planet Centre (MPC).

Unfortunately 23rd December was cloudy in my location so I had to wait. When a clear night presented itself on Boxing Day, there was a problem with my ephemeris predicition and I missed my target! Finally, using emphemeris from the JPL small body website I tracked it down as it raced northwards through Cancer.

Approaching so close meant that it was relatively bright (around magnitude 13) and its apparent motion across the sky very fast. The image below is a single 120s exposure, with 2008 EV5 slightly below left of centre showing clearly as a streak. Click here to download an animation of 2008 EV5 moving across the sky (10 one minute exposures). 


Make a Free Website with Yola.