Meaning: it is one of the meditation techniques by using any object for contemplation
                    Also called as murthy dhyana
                  Object can be any shape round or rising sun
Procedure:
Sit in padmasana and close the eyes, breathe normally. Hold the object of meditation mentally and contemplate on the object continuously
Duration: 5 to 10 minutes

Benefits:

Improves concentration
Calms  the mind

Meaning:  the natural breathing is hansa gayatri, according to yoga. It is also called ajapa gayatri
                    or  soham
Procedure:
Sit in padmasana with closed eyes. Breathe normally. Inhaling, mentally repeat “so” and while exhaling repeat “ham”.  Maintain concentration on the breathe
Duration: 5 to 10 minutes
Benefits:

Improves concentration
Calms the mind

Meaning: aum- pranava
                  AUM is composed of syllables “ a”,”u” and ‘m’.
                  It represents isvara. It is the universal sound/ sabda. It is the seed of all words and sacred mantra contemplation on this is one of the methods of dhyana
Procedure:
Sit in padmasana and close the eyes. Breathe normally. Mentally repeat AUM mantra of 3 and half matra. It should be continuous with full concentration
Duration: 5 to 10 minutes
Benefits:

Overcomes afflictions of mind
Overcomes obstacles to yoga

Meaning – nada – sound;  Anusandhana – contemptation
                     So, contemplating an anahata sound is nadanusandhana
Procedure:
Sit in padmasana and close the eyes and ears (by fore fingers). Concentrate and listen to the inner sound. The subtler sounds should be given priority over gross sounds
Duration: 5 to 10 minutes
Benefits:

Improves concentration
Calms the mind

Meaning; – one of the methods of dhyana
Procedure:
Sit in padmasana and gaze in front without blinking the eyes. Concentration should be drawn inwards
Duration:
Five minutes
Benefits:

Calms the mind
Improves concentration