Earlier quoted context omitted.
Image processing is a great way to get clean pictures but takes you further from direct observation. You could if extremely unlucky remove a supernova from your image not just meteors and cosmic rays.
Extremely unlikely. A supernova peaks over the course of days , and fades slowly over months to years . They also remain static relative to the background stars, as do all astronomical phenomena outside our Solar System, even over the span of a day.[1] Even a very-rapidly-peaking kilonova (neutron-neutron star collision) though they peak quite rapidly (short gamma-ray bursts, or SGBs, last about two seconds) have dur…
> A supernova peaks over the course of days
People do long exposures over hours and sometimes multiple days.
An algorithm assuming a static image could discard a relatively slow increase in brightness that shows up on say 10% of your samples.
So again not likely, but definitely something someone would prefer shows up despite being inconsistent.