suivi des satellites artificiels

14 août 2007




Aureole 2 rocket is the more visible of series Aureole. Its orbit is very elliptic 364*987 Kms*74°(ESA-NASA) so its visibility is function of the shift of the ascending node and also the rotation of perigee.

1)Rotation of the perigee.
The data computed with the elements above give:
Perigee precession –2.18 degrees every day

2)Ascending node precession –2.924° every day so
the visibility period is 123.12 days divided in 75.0 days (ZDT/ZAT)and 48.12 days(ZAT/ZDT)

3)Argument of perigee optimum APO
If the satellite is just over the site of observation at its perigee the magnitude will be major.
The computing of APO is
APO=arcsinus[(sin(48.7*3.14/180)*sin(74*3.14/180)]*180/3.14 where 48.7 is the latitude of the site of observation and 74 the inclination of the orbit. APO=51.414°
We have to keep in mind that relevant APO when the satellite is transiting south to north ie ZAT is 51.414°,but when transiting North to South ie ZDT relevant APO is 180-51.414=128.58°.
That is the case on 21th of August 2007.(128°)
We constructed the common scheme of visibility till December 07 (see Revosat previous years) adding the value of APO on ZDT line or ZAT line according to the date of observation and got two periods of major brightness;
On 14th August->24 August where omega ~133° so~128° and on 15 September->25 September where omega~65° so~51°.The satellite is near to the perigee.

Two periods of minor brightness :
On 1 November->10 November where omega ~ 327° far from 128° and 16 November->26 November where omega ~ 290° far from 51°.The satellite is far from perigee. It is near its apogee.

Posté par revosat à 06:15 - Commentaires [0] - Permalien [#]


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