Conventional round and curved lenses are the key element in refracting telescopes. While there have been advances in the materials used, the coatings, and the use of multiple lenses to correct distortions, basic lens design has not changed much since the time of Galileo.
Metalenses promise to revolutionize optics by replacing the bulky, curved lenses with a simple, flat surface.
A metalens takes a new approach to focusing light. Rather than exploiting the diffraction properties of glass, a metalens uses tiny pillars, typically made of titanium dioxide, to bend wavelengths toward the focal point.
The pillars are arranged in different patterns where each specific pattern focuses a different color of light. This short 2-minute video by Science Magazine does a good job of illustrating the concept in simple terms.
Recently, researchers from the Harvard School of Engineering have announced the development of the first single metalens that can focus almost the entire visible spectrum of light in the same spot. The Harvard metalens covers 470 nanometers (bold blue) to 680 nanometers (deep red) while a healthy eyeball reacts to wavelengths ranging from about 380 to about 700 nanometers. The Harvard metalens is a good prototype and additional advances may allow it to cover the whole visual spectrum.
A BC Company, NexOptic, has similar goals: to enable bigger apertures in small devices. They claimed to have developed a prototype telescope that was unveiled at the Macmillan Planetarium last year.
NexOptic has not revealed details on how their technology works but the prototype was evaluated on some moon images by a RASC-Calgary member, Larry McNish.
This is still early stage technology and a number of challenges remain for metalenses but hopefully it will enable dramatically smaller and lighter telescopes in the future.
2018 marks the 150th year since the Society’s inception. RASC national is planning a number of activities and events to celebrate.
The celebration begins on January 27h, 2018 with a cross-country Star Party that combines solar and lunar observing with local Centre events from the Atlantic coast to the Pacific and reaching northwards to encompass many of our Centres.
The activities of each Centre’s Star Party as well as messages from astronomical and civilian luminaries will be streamed for public viewing at https://www.youtube.com/watch?v=uN7IKkRwBK0 on January 27th, 2018 from approximately 10:00 am to 5:00 PST.
Later that evening, RASC Vancouver is hosting our annual Paul Sykes Memorial Lecture at the SFU Burnaby campus. Nancy Chabot, a planetary scientist at Johns Hopkins University, will be speaking on the topic of Ice On Mercury. The lecture is free and open to the public and more details can be found on our meetup post.
Paul Sykes Memorial Lecture
Saturday, January 27, 2018 7:30 PM to 9:30 PM
Room: SWH10081,Saywell Hall, adjacent to the Atrium
Simon Fraser University, Burnaby Campus
Topic: Ice on Mercury
Even though Mercury is the planet closest to the Sun, there are places at its poles that never receive sunlight and are very cold – cold enough to hold water ice! In this presentation, I’ll show the multiple lines of evidence that regions near Mercury’s poles hold water ice – from the first discovery by Earth-based radar observations to multiple data sets from NASA’s MESSENGER spacecraft, the first spacecraft ever to orbit the planet Mercury. These combined results suggest that Mercury’s polar ice deposits are substantial, perhaps comparable to the amount of water in Lake Ontario! Where did the ice come from and how did it get there? I’ll discuss these questions and others during this presentation of water ice on our Solar System’s innermost planet.
Our Observing Chair, Robert Conrad, is teaching an observational astronomy course every Saturday from January 6th to February 17th (except February 10th due to the long weekend). It’s offered through the continuing education department at SFU at the downtown campus and has a fee. The course starts at 10:30am and finishes at 12:30pm. It’s called “The Night Sky in your computer” and uses various simulation tools and apps to enhance your observing experience. As part of the course, you will gain access to many quick references and guides to enhance your observing experience.
Pascal Pillot-Bruhat, our light pollution chair, was interviewed for the article “Let’s not starve for starlight” in the Squamish Chief. The article notes that Squamish is taking steps to address light pollution:
The District of Squamish’s new Official Community Plan includes the recommendation that exterior lights should emit the minimum amount of light necessary. Outside lighting should be directed or shielded to illuminate the ground only and to prevent light pollution from encroaching onto adjacent properties, residential areas and environmentally sensitive areas
In preparation for Halloween, the RASC Vancouver observing group took at look at Mirach’s Ghost from the Trottier Observatory last Saturday night (Oct 28th, 2017).
Mirach’s Ghost is a faint galaxy that appears close to the bright star Mirach in Andromedae. It is not particularly scary or spectacular but the universe offers up some additional Halloween themed images and sounds.
The Ghost of Jupiter (NGC 3242)
This ghostly image shows the disembodied remains of a dying star, called a planetary nebula. Planetary nebulas are sun-like stars that are in a late-stage of their life when their outer layers have sloughed off and are lit up by ultraviolet light from the central star. The Ghost of Jupiter is located approximately 1,400 light-years away in the constellation Hydra.
The Ghost of Saturn (NGC 7009)
The Saturn nebula is a planetary nebula located in the constellation of Aquarius. Its name derives from its shape, which resembles everyone’s favourite ringed planet seen edge-on.
The Owl Nebula (M97)
The Owl Nebula is a planetary nebula located near the bottom of the Big Dipper’s bowl. It is one of the fainter objects in the Messier Catalog.
The Phantom Galaxy (M74)
Messier 74 (M74) is a grand design spiral galaxy located in the constellation Pisces. It has a diameter of 95,000 light years, almost the same size as the Milky Way. The galaxy is home to about 100 billion stars.
The Outer Limits Galaxy (NGC 891)
NGC 891 is an edge-on spiral galaxy located about 3.5o east of the double-star Almaak in Andromeda. The Hubble Space Telescope has rendered stunning detailed views of this system with its intricate dark dust lanes across its centre. The name “Outer Limits” galaxy came about because the galaxy was featured in the credits of an early incarnation of the famous “Outer Limits” TV series.
The Witch’s Broom Nebula (NGC 6960)
Also known as the Veil Nebula, the Witch’s Broom is a faint supernova remnant located in the constellation Cygnus. The Witch’s Broom actually spans about 35 light-years. The bright star in the frame is 52 Cygni, visible with the unaided eye from a dark location but unrelated to the ancient supernova remnant.
NASA’s Spooky Space Sounds
NASA has put together a compilation of elusive “sounds” of howling planets and whistling helium that is sure to make your skin crawl