Hi,
I'm making a function to calculate the topocentric position of any meteor shower for a given date, but when on the process of calculating the right-ascension and the declination it is somehow based on J2000.0 RA and declination values and a drift value for each of them. I don't really understand how this drift is applied in the calculations... For the information I have found, the drift values are per day (Stellarium handbook), but should I apply the number of days (and hours and minutes) since J2000.0 times the drift? Looking at Stellarium values of the Perseids, it seems that RA and Decl change day by day isn't as much as the drift should affect.
Here some examples for Perseids meteor showers in Stellarium:
2000 January 1, 11:58:56 UTC: RA: 3h12m01.72s Dec: +57º69'59.4"
2000 January 2, 11:58:56 UTC: RA: 3h12m01.72s Dec: +57º59'59.4"
2000 January 3, 11:58:56 UTC: RA: 3h12m01.74s Dec: +57º59'59.4"
2000 February 1, 11:58:56 UTC: RA: 3h12m02.00s Dec: +58º00'00.8"
2000 March 1, 11:58:56 UTC: RA: 3h12m02.38s Dec: +58º00'02.6"
Drift values (radiant drift/per day): RA: 0h04m48.0s Dec: +0º12'00"
As can be seen here, the difference between RA and Dec values day by day, and month by month does not fall near the drift values.
Maybe there's some other variable that I'm not counting and counters the effect of the drift?
Thank you