Table 3. The three reference stars

Star #	Pixel coordinate (x,y)	RA-coordinate (°)	Dec-coordinate (°)	HIP
20	328.81, 437.46	185.0822	26.61975	60170
30	364.46, 394.72	186.0772	26.09861	60514
40	416.7, 383.71	187.159	26.22697	60880

RA, right ascension; Dec, declination; HIP, hipparcos star number.