57424 Caelumnoctu, 27th September 2007
At magnitude 18.95 this was never going to be easy! With a full moon 90 degrees away and some thin haze I must have been
mad but here it is!
For the first time in months the gremlins hit the camera and I had trouble locating the field but eventually I started
taking 1 minute subs. I re-checked the ephemeris and realised the asteroid would be swamped behind the light of a 12th
magnitude star so I continued taking subs until I thought it would be clear of the star. I kept seeing fleeting glimpses
of what might have been an image but it was 4 in the morning - was it just noise in the image?
After processing the images and stacking 6 frames at a time most of the stacks clearly showed 'The Sky At Night'.
The
annotated image below was taken between 03:23 and 03:27UT and is a stack of 6x1min unfiltered subs.
The animation shows the motion between 02:48 and 03:47UT. The astrometric
position measured with 'Astrometrica' matches very well with the position
from JPL Horizons for 03:25UT. All images taken with the 14" unfiltered
at f5.24 and the Art 285 CCD camera.
Astrometry
| Measured | JPL Horizons | Difference (Arc sec) |
||||||
| Mag | Time UT | RA h:m:s | DEC d:m:s | RA h:m:s | DEC d:m:s | RA | DEC | |
| 18.95 | 03:25 | 05:24:44.69 | +33:34:25.0 | 05:24:44.73 | +33:34:25.3 | 0.6 | 0.3 | |

