Updated 2022 January 7
The equations for the light curves of comets that are currently visible use only the raw observations and should give a reasonable prediction for the current brightness. If the comet has not yet been observed or has gone from view a correction for aperture is included, so that telescopic observers should expect the comet to be fainter than given by the equation. The correction is about 0.033 per centimetre. Values for the r parameter given in square brackets [ ] are assumed. The form of the light curve is either the standard m = H0 + 5 log d + K0 log r or the linear brightening m = H0 + 5 log d + L0 abs(t - T + D0) where T is the date of perihelion, t the present and D0 an offset, if L0 is +ve the comet brightens towards perihelion and if D0 is +ve the comet is brightest prior to perihelion.
Observations of new comets in 2022 are given in ICQ format.
Full details of recently discovered objects will not appear until they are available on the CBAT web pages. The actual accuracy of preliminary orbits is often (nearly always) much worse than the published accuracy implies. In part this is because each orbital solution is treated as a mathematical construct and does not take account of observational error. JPL does publish the errors, whereas the MPECs do not.