Look east before sunrise on the 15th of July for a great trio – a skinny crescent Moon will be hanging over the eastern horizon, just below bright Jupiter and above even brighter Venus. Venus will continue hanging brilliantly in the pre-dawn sky for the rest of the year, before finally sinking too close to the Sun at New Year’s. As an inferior planet Venus is only ever visible relatively near the Sun, so appears as either the Morning Star or the Evening Star, but obviously not both at the same time! A fragment of Ibycus, a Greek poet from the 6th century BC, states:
“Eosphoros (Dawn-Bringer) and Hesperos (Evening-star) are one and the same, although in ancient times they were thought to be different.”
In the morning Venus was also known as Phosphorus (light bringer) – which translates to Latin as Lucifer. But in the English speaking world Lucifer has a much different connotation – being identified with Satan. It is believed this came from an interpretation of Isaiah 14:12 as referring to the casting out of fallen angels from heaven, rather than a continued taunt of a king of Babylon. The King James Version is:
“How art thou fallen from heaven, O Lucifer, son of the morning! How art thou cut down to the ground, which didst weaken the nations!”
A more modern translation is:
“How you are fallen from heaven, O Day Star, son of Dawn! How you are cut down to the ground, you who laid the nations low!”
Image credit: Large Binocular Telescope Observatory
In the astronomy world, LUCIFER (an acronym for LBT Near Infrared Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research) is a new instrument hooked up to the Large Binocular Telescope in Arizona. The LBT, as it is known, is a telescope consisting of a pair of 8.4m mirrors on one mount. Combined they have the light gathering equivalent of an 11.8m telescope – effectively the largest optical telescope in the world. Adaptive optics are used to correct for any atmospheric distortion by manipulating the mirror in real time to cancel out the blurring. The mirror is capable of making adjustments every one thousandth of a second, with accuracy to better than ten nanometers.
LUCIFER is a pair of near-infrared detectors connected to the scope. The German built instruments can swap between imaging with a camera or gathering spectra. Because they operate in the near-infrared part of the spectrum, they have to be cooled to -213° Celsius, or else they would end up detecting the heat of themselves, rather than the object they should be observing. The heat of the Earth’s atmosphere can be subtracted from images electronically. Near-infrared observations are vital in the study of the stellar nurseries that host the formation of stars and planets. These nebulae are generally opaque to visible light, but reveal themselves in infrared and the regions of planet formation are generally cool – so are best viewed in infrared! Our galactic centre is also being studied in the infra-red, as are extragalactic objects. LUCI itself is housed in a large cryogenic chamber and has a robotic arm to swap in and out masks to control the spectrometry. The first few images with LUCIFER were taken in early 2010, after a decade of design and testing. This instrument should rival space telescopes for resolution, at a fraction of the cost (its only 120 million dollars!).
This episode of “What is the Stars?” was first broadcast on July 9, 2012. Listen live on RTÉ lyricfm Mondays and Fridays at 22:45. 
