Mu Herculis A is the bright star in the center of the field. Its spectral class is G5, meaning that it is very close in size and luminosity to our Sun (G2). It forms a binary star with the reddish star immediately above it (Mu Herculis B), with a measured separation of 286 astronomical units or about 3.5 times the diameter of Pluto's orbit.
Mu Herculis B is a red dwarf star (spectral class M3), and itself is a close double star with a separation of 11 astronomical units. Recent observations suggest that Mu Herculis A may itself be a close double, in which case this is a quadruple star system. The system is 27 light years from Earth, as measured by trigonometric parallax.
Double Star Mu Herculis
Date Taken:April 13, 2010
Location Taken: Conditions of Location:FWHM 2.1
Equipment Used:14.5" Ritchey-Chretien telescope, SBIG STL11000 CCD camera, Astrodon RGB filters, TCC, PIR, remote guide head used with Takahashi Sky90 for autoguiding, T-Point used for polar alignment (required for each imaging session due to my portable setup).
Processing Used: Distance from Location:27 light years
Constellation:Hercules
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