Posted by Eliot Hall at 12:08 on 2013 Dec 08
So to summarise (let me know if I have any of this wrong).The sky’s limiting magnitude will be determined by seeing (particles, light pollution, and turbulence). Given perfect conditions mag. 20-22 may be possible, but around mag. 18-19 is possible average conditions. (I’m now starting to understand why they put all those multi-million pound observatories on top of dry mountains).Focus and accurate tracking/guiding is critical to maximise the signal received. Unfiltering the camera will allow more light onto the sensor. (Won’t this spread the light across more pixels degrading the definition of the star?)Using a bigger aperture or a more sensitive camera will only decrease the time to which you get to the sky’s limiting magnitude (however shorter exposures are useful for faster moving objects).Astrometrica will predict the path of the asteroid across the field of view and align the frames accordingly for stacking thus improving SNR. I’ve tried this on some other data I took a few days later and found an asteroids (a case of reading the manual for me).Eliot