Building a mirror for any giant telescope is no simple feat. But the recent castings of the 15-metric ton, off-axis mirrors
for the Giant Magellan Telescope forced engineers to push the design & manufacturing process beyond all previous limits.

Casting a $20 Million Mirror for the World’s Largest Telescope
https://www.youtube.com/watch?v=M2f4zepwcy8

The long and short of it: Iron-rich stars host shorter-period planets | SDSS | Press Releases
http://www.sdss.org/press-releases/long-short-iron/

Astronomers with the Sloan Digital Sky Survey (SDSS) have learned that the chemical composition of a star
can exert unexpected influence on its planetary system — a discovery made possible by an ongoing SDSS survey
of stars seen by NASA’s Kepler spacecraft, and one that promises to expand our understanding of how extrasolar
planets form and evolve.

https://www.nasa.gov/.../new-sofia-observations-help-unravel-mysteries-of-the-birth-of-colossal-suns

Astronomers are observing star-forming regions in our galaxy with NASA’s flying telescope, the Stratospheric Observatory for Infrared Astronomy, SOFIA, to
understand the processes and environments required to create the largest known stars, which tip the scales at ten times the mass of our own Sun or more.

The research team, led by James M. De Buizer, SOFIA senior scientist and Jonathan Tan at Chalmers University of Technology, Gothenburg, Sweden and the University
of Virginia, has published observations of eight extremely massive and young stars located within our Milky Way Galaxy. SOFIA’s powerful camera, the Faint Object
infraRed Camera for the SOFIA Telescope, known as FORCAST, allowed the team to probe warm, dusty regions that are heated by light from luminous, massive stars that
are still forming. SOFIA’s airborne location, flying above more than 99 percent of Earth’s infrared-blocking water vapor coupled with its powerful instruments, make
it the only observatory that can study the stars at the wavelengths, sensitivity, and resolution necessary to see inside the dense dust clouds from which these
stars are born.

https://www.nasa.gov/image-feature/new-day

"A view of the sunrise from the ISS is a perfect start to a new day," so said @Anton_Astrey, otherwise known as cosmonaut
Anton Shkaplerov, who is currently stationed aboard the International Space Station, orbiting 250 miles above the Earth.

Hurá!!

První segmenty primárního zrcadla dalekohledu ELT úspěšně odlity | ESO Česko
http://www.eso.org/public/czechrepublic/news/eso1801/?lang

Německá firma SCHOTT ve své továrně ve městě Mainz úspěšně odlila prvních šest segmentů primárního zrcadla pro dalekohled ELT. Hlavní zrcadlo dalekohledu ELT bude
mít průměr 39 m a bude ho tvořit celkem 798 šestiúhelníkových segmentů. Po dokončení v roce 2024 by se dalekohled ELT měl stát největším optickým teleskopem na světě.

Primární zrcadlo připravovaného dalekohledu ELT (Extremely Large Telescope) bude s průměrem 39 m zdaleka největším, jaké bylo kdy osazeno v jakémkoliv dalekohledu
pro viditelnou nebo infračervenou oblast. Takto velké zrcadlo je však příliš velké na to, aby bylo možné ho vyrobit z jednoho kusu skla. Proto bude sestaveno ze 798
šestiúhelníkových segmentů o průměru 1,4 m a tloušťce 5 cm. Jednotlivé díly budou uloženy tak, aby mohly pracovat společně jako jedna optická plocha, která posbírá
dvacetmilionkrát více světla než lidské oko.

ESOcast Light 145: First ELT Main Mirror Segments Successfully Cast
https://www.youtube.com/watch?v=85Qcbn8nlaM

First PEPSI data release — English
http://www.aip.de/en/news/science/first-pepsi-data-release

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona
released its first batch of high-spectral resolution data to the scientific community. In a series of three papers in
the European journal Astronomy & Astrophysics, the PEPSI team presents a new spectral atlas of the Sun, a total of 48
atlases of bright benchmark stars, and a detailed analysis of the chemical abundances of the 10-billion year old planet-
system host Kepler-444.

Saturn's moon Titan sports Earth-like features | Cornell Chronicle
http://news.cornell.edu/stories/2018/01/saturns-moon-titan-sports-earth-features

Using the now-complete Cassini data set, Cornell astronomers have created a new global topographic map of Saturn’s moon Titan that has opened new windows into
understanding its liquid flows and terrain. Two new papers, published Dec. 2 in Geophysical Review Letters, describe the map and discoveries arising from it.

Creating the map took about a year, according to doctoral student Paul Corlies, first author on “Titan’s Topography and Shape at the End of the Cassini Mission.”
The map combines all of the Titan topography data from multiple sources. Since only about 9 percent of Titan has been observed in relatively high-resolution
topography, with 25-30 percent of the topography imaged in lower resolution, the remainder of the moon was mapped using an interpolation algorithm and a global
minimization process, which reduced errors such as those arising from spacecraft location.

The map revealed several new features on Titan, including new mountains, none higher than 700 meters. The map also provides a global view of the highs and lows
of Titan’s topography, which enabled the scientists to confirm that two locations in the equatorial region of Titan are in fact depressions that could be either
ancient, dried seas or cryovolcanic flows. The map also revealed that Titan is a little bit flatter – more oblate – than was previously known, which suggests
there is more variability in the thickness of Titan’s crust than previously thought.

W. M. Keck Observatory Achieves First Light with NIRES W. M. Keck Observatory
http://www.keckobservatory.org/recent/entry/NIRES

Astronomers at W. M. Keck Observatory have successfully met a major milestone after capturing the very first
science data from Keck Observatory’s newest instrument, the Caltech-built Near-Infrared Echellette Spectrometer (NIRES).

The Keck Observatory-Caltech NIRES team just completed the instrument’s first set of commissioning observations and achieved
“first light” with a spectral image of the planetary nebula NGC 7027.

“The Keck Observatory continually strives to provide instrumentation that meets the high aspirations of our scientific
community and responds to changing scientific needs,” said Keck Observatory Director Hilton Lewis. “NIRES is expected to be
one of the most efficient single-object, near-infrared spectrographs on an eight to ten-meter telescope, designed to study
explosive, deep sky phenomena such as supernovae and gamma ray bursts, a capability that is in high demand.”

“The power of NIRES is that it can cover a whole spectral range simultaneously with one observation,” said Keith Matthews,
the instrument’s principal investigator and a chief instrument scientist at Caltech. “It’s a cross-dispersed spectrograph
that works in the infrared from where the visual cuts off out to 2.4 microns where the background from the thermal emission
gets severe.”

Large asteroid 2018 AH flew past Earth at 0.77 LD, 2 days after discovery

A relatively large newly discovered asteroid designated 2018 AH flew past Earth at 0.77 LD / 0.00199 AU (~297 699 km / 184 982 miles) on January 2, 2018.
This is the 1st known asteroid to flyby Earth within 1 LD this year, 54th since January 1, 2017 and the largest within 1 LD since 2011.

2018 AH was first observed at ATLAS-MLO, Mauna Loa on January 4, 2018, two days after its close approach to Earth. The closest approach to Earth took place
at 04:25 UTC on January 2 at a speed (relative to the Earth) of 13.76 km/s.

It belongs to the Apollo group of asteroids, the most common one, and it has an estimated diameter of 84 - 190 m (275 - 693 feet), making it the largest
known near-Earth object to flyby Earth within 1 lunar distance since 2011.

It is also the 9th largest known near-Earth object (asteroids + comets) to flyby Earth within 1 lunar distance ever. Over the past 18 years, only 2 asteroids
larger than 2018 AH flew past us this close and 8 since 1918.

As of January 5, 2018, there are 17 566 known near-Earth objects around our planet, 17 460 of them are asteroids. Of the total number of known NEOs,
7 999 have an estimated diameter roughly 140 m (460 feet) or larger, including 2018 AH.

Gravitational Waves Measure the Universesu201801 | www.cfa.harvard.edu/
https://www.cfa.harvard.edu/news/su201801

The direct detection of gravitational waves from at least five sources during the past two years offers spectacular confirmation of Einstein's model of gravity and space-time. Modeling of these events has also
provided information on massive star formation, gamma-ray bursts, neutron star characteristics, and (for the first time) verification of theoretical ideas about how the very heavy elements, like gold, are produced.

Astronomers have now used a single gravitational wave event (GW170817) to measure the age of the universe. CfA astronomers Peter Blanchard, Tarreneh Eftekhari, Victoria Villar, and Peter Williams were members
of a team of 1314 scientists from around the world who contributed to the detection of gravitational waves from a merging pair of binary neutron stars, followed by the detection of gamma-rays, and then the
identification of the origin of the cataclysm in a source in the galaxy NGC4993 spotted in images taken with various time delays at wavelengths from the X-ray to the radio.

An analysis of the gravitational waves from this event infers their intrinsic strength. The observed strength is less, implying (because the strength diminishes with distance from the source) that the source
is about 140 million light-years away. NGC4993, its host galaxy, has an outward velocity due to the expansion of the universe that can be measured from its spectral lines. Knowing how far away it is and how fast
the galaxy is moving from us allows scientists to calculate the time since the expansion began – the age of the universe: between about 11.9 and 15.7 billion years given the experimental uncertainties.