IC 4592, The Blue Horsehead Nebula, is a reflection nebula in the constellation Scorpius, about 424 light-years from earth. It is about 19 light-years in diameter, primarily illuminated by the young, bright blue multiple-star system, Jabbah, left of the center of the image, which means “The Forehead” in Arabic and refers to its position at the head of the mythical scorpion after which the constellation is named. The nebula is composed of a cold, diffuse, mainly hydrogen, molecular cloud through which the brighter stars are shining, illuminating them with the intense blue color of the stars rather than exciting them into fluorescence. The brown-colored nebula is illuminated by the relatively faint, mature, yellow stars in the area. The bright blue illuminating stars are quite young, being only about 5 million years old, and are spreading apart so fast that they have noticeably changed position in the last century. In this image, a particularly interesting star is in the upper left, 9 Scorpii, the smaller of the pair of bright stars. It is moving through space at an enormous speed of 224,000 miles per hour (1,000 kilometers per second). The image is composed of 85, 600-second exposures through luminance (clear), red, green, and blue filters, for a total exposure time of 14 hours and 20 minutes, imaged through a Takahashi FSQ 106ED telescope using an FLI PL16803 camera belonging to Telescope Live, at the Heaven’s Mirror Observatory near Yass, NWS, Australia during 7 sessions from May through August of 2021. It was compiled, calibrated, registered, and the final image created by Jeff McClure using Astro Pixel Processor v.1.803.2 and Adobe Photoshop Lightroom Classic v. 11.2 in February and March 2022.
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