You explained the method of offering superogatory prayers.I would like to further discuss on this.My queries follow: 1.Many scholars have said that all the hadiths on Tasbeeh prayer are weak.Hence they say that it is Bidah to pray Tasbeeh prayer.Do you consider Tasbeeh prayer to be Bidah?.If not why?.please give the basis of the opinion 2.Regarding the Eclipse prayer you said that it is generally a two-rakat prayer.Muslims generally pray that with two rukus and two sajdas in each rakat depending on the hadiths in Bukhari.Please let us know if they are doing right.Please let us know why you didn’t include Eclipse prayer in your definition of Sunnah and yet include it as a part of Islam.
Offering any supererogatory prayers at any time of the day cannot be termed as a Bid`ah. For details, please see: The Position of Some Supererogatory Prayers
If one considers the chain of narratives reporting ‘Tasbeeh’ prayer to be weak, one should then not ascribe this prayer to the Prophet (pbuh). Nevertheless, offering any prayers, without considering them a part of the Sunnah cannot be termed as a Bid`ah.
The method of offering eclipse prayers has not been prescribed by the Prophet (pbuh). In our understanding, offering prayers at the time of eclipse is only one of the applications of the directive entailed in the Qur’an to turn towards God in times of fear and trouble.
As for the reason of the two rukus in the eclipse prayer, it seems that the Prophet (pbuh) desired to keep in prostration till the time that the eclipse had ended. At rising from the ruku, when the Prophet (pbuh) observed that the eclipse had not yet ended, he went back into his prostration. This does not mean that a separate method was prescribed for offering the eclipse prayers.