Servo motor

I am working on a tracker project which has azimuthal and elevations motion,
Help me with suitable servo motor with encoder, controller/Drive
Torque: 6nm
RPM: 10
Voltage: 15VDC

Thanks Hussain

6Nm (newton-metres), not 6nm (nanometres!!)

You need a gearmotor with lots of reduction - most motors run 3000 to 15000 rpm

You say servomotor with encoder - thats a motor and an encoder. A servomotor is the
combination of motor, encoder and controller (which will be done by the Arduino I imagine).

Commercial servomotors are very expensive (but typically extremely high performance).

Something like a 300:1 reduction 15 to 20W gearmotor ought to do - so long as the output gear
is rated for above 6Nm of course.

10rpm is about 1 rad/second, so the mechanical output power is 6Nm x 1rad/s = 6W. Allowing
for several stages of gearing, expect mechanical loses of at least 50%, hence the 15 to 20W rating.

Something like this (but with a definite power and torque rating - these are too small):

You might have to consider combining a higher speed gear motor with a final belt drive to increase the
range of motors available - for instance a stepper motor with 1Nm torque and 6:1 reduction belt
would be another possibility, though needing more power.