How do I tune the parameters of cv2.houghcircle() function of OpenCV-python to get the best results?

I am using OpenCV-Python 3.2 package with Python 3.6 but i am unable to get the desired result.

My task is to detect the circles from an image for that i use HoughCircle Algorithm but output is not appropriate.

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My Code:

//python program

import cv2

import numpy as np

planets = cv2.imread('solar.jpg')

gray_img = cv2.cvtColor(planets, cv2.COLOR_BGR2GRAY)

img = cv2.medianBlur(gray_img, 5)

#img = cv2.GaussianBlur(gray_img, (3, 3), 0)

cimg = cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)

circles = cv2.HoughCircles(img, cv2.HOUGH_GRADIENT, 1, 120,

param1=179, param2=28, minRadius=50,

maxRadius=141)

circles = np.uint16(np.around(circles))

for i in circles[0,:]:

# draw the outer circle

cv2.circle(planets,(i[0], i[1]), i[2],(0, 255, 0), 2)

# draw the center of the circle

cv2.circle(planets,(i[0], i[1]), 2, (0, 0, 255), 3)

cv2.imwrite("planets_circles.jpg", planets)

cv2.imshow("HoughCirlces", planets)

cv2.waitKey()

cv2.destroyAllWindows()

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My Output:

My Input:

#Python #OpenCV #ImageProcessing