P. Clay Sherrod Oct 27 8:19 AM
----- Original Message -----From: Rolf StadelmaierSent: Sunday, October 27, 2013 10:14 AMSubject: Re: [guide-user] Comets mag, how true?Aha, I see there are most regrettable uncertainties in play.At least the informations about position are utmost close.BTW, despite the comet is almost lost in noise in my pictures,the program astrometrica (H. Raab) could find out a magnitudefor the comet between V = 13.9 and V = 14.1, very faint so farbut seems relativly correct.Thank you very much for your enlightening explanations andgood wishes Mr. Sherrod.CS,Rolf Stadelmaier
You are correct that the magnitudes given are far, far from actual magnitudes.
These are magnitudes that were derived from the basic sets of orbital elements that
Guide (and other programs, including the MPCORB) uses to extrapolate the magnitude
given the parameters of the orbit.
Rarely are the comets anywhere close to what these provide; there are many comets
listed that are not even visible, much less as bright as given and others are
somewhat brighter than the prediction suggests.
On comets, never go by what is listed by others. Always determine for yourself using
comparison stars, either visually or photometrically via CCD.
An excellent article that sums up all of the methods that are accepted is given at:
Best of luck on your comet observing.
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West