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Hi Pierre
For rocks moving at a more leisurely pace and maybe 3 or 4 Lunar Distances out, I have found that The Sky X Pro usually puts them in the right spot on my imaging camera.
2025 KF would have been at the extreme end of difficulty to cut your teeth on as it was moving so fast and I believe your positional and time data needs to be accurate when they are this close and whizzing by to minimize parallax errors.
For 2025 KF, I generated an Ephemeris Table via the JPL Horizons website and then selected a time slot some 3 or 4 minutes ahead of the current time.
This rock was moving so fast I selected 1 minute intervals for the Table and the associated RA and DEC coordinates, so I could slew to a time/position combination and then start the exposure sequence.
After slewing to an RA and DEC position, I waited and sure enough, the faint trail appeared. The APS-C sized ASI2600MM gives a nice FOV compared to smaller sized sensors.
Phew!
The JPL Horizons website is reasonably straightforward to use, and you can play about with the various Input Fields to produce an Ephemeris that meets your needs. I keep it simple to Time (UT) and Apparent RA and DEC rather than J2000.
It might be good to practice on one of the slower moving classical Asteroids such as Ceres, Vesta, Pallas, etc. so you can establish a good workflow and practices.
Happy hunting – it can be so much good fun when you manage to locate one of the close approaches.
Dennis
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