Euclid is a space based telescope launched by ESA (European Space Agency) in July 2023. Since then it has traveled to its home at the L2 Lagrangian point in space about a million miles from Earth. And sent back first images of what it has seen. Whenever a new space based observation mission is launched, I am curious to find out how it is different from other missions in the past.
Euclid was launched on SpaceX’s workhorse rocket Falcon 9 from Kennedy Space Center in Florida (closer to my home). Why would ESA launch from the US ? ESA’s Arianne 6 rocket was not ready at that time while Arianne 5 was retired. Due to the ongoing Ukrainian war, Russian launch options were not feasible either. Since then Euclid has traveled to the L2 Lagrangian point on the Sun-Earth axis, away from Earth and Sun. It is the same parking lot where the James Webb Space Telescope is also positioned. Balanced by the gravitational pull of the Earth and the Sun, the Telescope consumes minimal energy and its fuel is expected to last for six years. The picture shown below, courtesy NASA shows the various Lagrangian points. Though not drawn to scale, it illustrates the concept well.
Euclid’s mission is to look at large swaths of sky and produce a survey of all the galaxies and their red shifts in the form of a 3D map. The distribution of the galaxies shows how much dark mass is around. While dark matter cannot be seen, its effect can be felt. While the red shift of the galaxies, which measures how fast the galaxies are receding from each other, measures the dark energy. Unlike the narrowly focused telescopes like James Webb, it will not focus on any individual galaxy or any other object. But would be observing and constructing a panoramic view of the universe dominated by dark matter and dark energy. The sharp pictures produced would be built from 600 million pixels each.
Euclid will observe galaxies which have dark matter in front of them. Any big lump of matter sitting between us and the object, creates a distorted view of the object behind because light bends in the presence of a gravitational field. This concept is known as gravitational lensing. Regular gravitational lensing causes arcs, rings and multiple images of the objects behind. When dark matter is in front, it produces a weak gravitational lensing instead, It helps us study the dark matter by looking at the images.
Another set of observations would involve Baryonic Acoustic Oscillations (BAO) which are remnants of the Cosmic Microwave Background (CMB) radiation. The structure of the universe shows clustering of galaxies in pairs and separated by some distance. This distance is related to the sound waves in plasma in the early universe. Plasma represents the ancient cosmic soup consisting of ions. The BAO is related to these sound waves. The BAO would give some clues about the universe’s expansion and the strength of dark energy at different times during the universe’s lifetime.
Coming to the first light received by Euclid, is a galaxy nicknamed the “Hidden Galaxy” closer to our Earth. Given below is the picture courtesy ESA. It looks like an ordinary picture taken by any other telescope. The galaxy is located behind our galaxy, as viewed from edge on. We do not have a ringside view of this galaxy. Instead the galaxy is behind a mountain of dust and gas which block our view. Euclid’s piercing vision made this image possible. And this is just the beginning.
The Greek mathematician Euclid is considered as the father of geometry. He lived in Alexandria about twenty three hundred years ago. The Euclid mission will map the geometry of the universe. We will have to wait for six years to see a comprehensive 3D map of our dark universe. I am waiting to get this poster to be hung in my home.
How NASA’s Roman Space Telescope Will Chronicle the Active Cosmos NASA’s Nancy Grace Roman Space Telescope will pair space-based observations with a broad field of view to unveil the dynamic cosmos in ways that have never been possible before. “Roman will work in tandem with NASA observatories such as the James Webb Space Telescope and Chandra X-ray Observatory, which are designed…more
-scitechdaily
Cosmic Clarity: Gravitational Lensing Reveals the Fine Fabric of Dark Matter A team of researchers has used the gravitational lensing of the MG J0414+0534 system, observed with ALMA, to map dark matter distribution in unprecedented detail, confirming theories of cold dark matter and paving the way for further discoveries about the universe’s dominant but elusive component…more
-phys.org
Scientists find 14 new transient objects in space by peering through the ‘Christmas Tree Galaxy Cluster’ An international team of scientists, led by University of Missouri’s Haojing Yan, used NASA’s James Webb Space Telescope (JWST) to discover 14 new transient objects during their time-lapse study of galaxy cluster MACS0416—located about 4.3 billion light years from Earth—which they’ve dubbed “The Christmas Tree Galaxy Cluster.”…more
-skyandtelescope
Asteroid will cover Betelgeuse, may reveal its visible surface Astronomers are gearing up for an unusual celestial event: an asteroid’s occultation, or total covering, of an iconic star. Imagine your favorite constellation without one of its brightest stars. For a brief moment on December 12th, this may happen to Orion, at least for viewers in a narrow stretch from central Asia and southern Europe to Florida and Mexico….more
-sciencealaert.com
Dozens Of Massive ‘Runaway’ Stars Found Fleeing The Milky Way The Milky Way can’t hold onto all of its stars. Some of them get ejected into intergalactic space and spend their lives on an uncertain journey. A team of astronomers took a closer look at the most massive of these runaway stars to see if they could find out how they get ejected….more
-phys.com
One step closer to unveiling dark matter with ARRAKIHS The ARRAKIHS consortium, for which EPFL has the science lead, has just successfully passed the mission definition review of the project, a very important first milestone towards full completion of the mission preparation. ARRAKIHS is a satellite selected by ESA to address the nature of dark matter, to be launched in 2030…more
-debrief.org
European satellite spots mysterious glow coming from Mars A European Space Agency satellite has detected a mysterious glow coming from Mars. Measured in the visible spectrum with the NOMAD-UVIS instrument on board the European Space Agency (ESA) Trace Gas Orbiter (TGO) satellite, the unexpected glow emanates from the night side of Mars and was observed in the planet’s upper atmosphere…more
-space.com
1st black hole ever imaged by humans has twisted magnetic fields and scientists are thrilled Spiraling light at the edge of a distant supermassive black hole could help matter escape from being consumed by this cosmic titan. The supermassive black hole of M87 — also known as M87* — has a mass equal to around 6.5 billion suns. It especially came to the public’s attention in 2019 when an image of M87*, captured by the Event Horizon Telescope (EHT)…more
-space.com
Euclid ‘dark universe’ telescope captures 1st full-color views of the cosmos (images) On Tuesday (Nov. 7), astronomers hailed the Euclid telescope’s ability to capture stunning intricacies of the universe in remarkably few hours as they revealed the mission’s first portfolio of full-color images. “We have never seen astronomical images like this before, containing so much detail,” René Laureijs, Euclid project scientist, said in a statement…more
-NYT
Oldest black hole discovered dating to 470 million years after the Big Bang Scientists have discovered the oldest black hole yet, a cosmic beast formed a mere 470 million years after the Big Bang. The findings, published Monday, confirm what until now were theories that supermassive black holes existed at the dawn of the universe…more
After various adventures in Europe and Africa, Captain John Smith helped found Jamestown in Virginia in 1607. He also suggested the name “New England” for the northeastern part of our country after having explored its coast. Not many are aware, however, that according to one story he was an early proponent of the first and second laws of thermodynamics.
By way of background, there was an alliance of the original inhabitants of Tidewater Virginia, headed by Chief Powhatan. Captain Smith was visiting Powhatan when the chief concluded that Smith was a major problem. Powhatan’s daughter Pocahontas acted as interpreter for what then transpired.
Powhatan: Captain Smith, you and your companions have invaded our land. Not only that, but your firearms make loud bangs. I have decided to do away with you.
Smith: Honorable Chief, we mean no harm. We want to live in peace with you and your people. Besides, I know some physics that you might find helpful. Please let me explain.
P: “Physics” sounds like another English trick. I’ll listen to your last words.
S: Thank you, Chief. First of all, energy is conserved. It can’t be created or destroyed, but it can be transformed from one form into another. For example, the chemical energy contained in your arm muscles can be partially converted into kinetic energy of your club, and thence to fragmentation of my head. Meanwhile, some heat will have been generated and lost, but if you carefully add everything up, it will all balance out.
But now comes the worst part. Entropy, in other words the disorder of the universe, will have been increased. Whatever help I might have otherwise been able to give you to improve your material condition would be lost forever if you kill me. Please consider all these facts.
P: Very interesting, Smith. I appreciate the science lesson. However, you are still going to die and we will just have to clean everything up. I’m sure the universe will survive this minor increase in its entropy. Put your head on this rock.
Pocahontas (interrupting): Father, what he’s saying makes a lot of sense. For example, suppose I visit England. I could bring back some more physics and other things to help us. If you kill Captain Smith, the Jamestown people will be very angry and this might never happen. Please reconsider.
P: Sorry, my child. Captain Smith is toast. Here goes!
Pocahontas: Over my dead body! I’m putting my head over Captain Smith’s. Go ahead and hit if you really must, but you’ll be sorry!
P (relenting): OK, Smith, get up. You can live, at least for now. By the way, speaking of bangs, what’s all this I’ve been hearing about the Big Bang that is supposed to have started the whole universe? You say energy can’t be created, but it was, right? And the Big Bang made about as much disorder as possible, didn’t it? How could things get any worse than that? You and your physics can go pound sand. And don’t get me going on string theory!
S: Thanks, Chief. We’ll talk again soon. Bye now!
Author’s note: The story about Captain Smith being saved by Pocahontas relies on the word of Smith himself, in a 1616 letter to King James’s wife, Queen Anne. I’ve filled in the missing parts.
No disrespect is intended to Chief Powhatan. In fact, he was honored by the creation of Powhatan County in 1777. Pocahontas did go to England as the wife of John Rolfe. She died in Kent at about 20 or 21. Astronomer Percival Lowell is said to have been one of her descendants.
Late Autumn at Peyton Hall The November, 2023 meeting of the AAAP will take place in Peyton Hall (on the campus of Princeton University) on Tuesday, November 14th at 7:30 PM. As usual, the meeting is open to AAAP members and the public. Participants can join the meeting in-person at Peyton Hall or log in to the Zoom session as early as 7:00 pm to chat informally before the meeting begins. This evening’s guest speaker is Gary A. Rendsburg of Rutgers University. Prof. Rendsburg will present “The Jewish Calendar: An Ingenious Integration of the Lunar and Solar Cycles.”
Options for Attending the November Meeting You may choose to attend the meeting in person or participate via Zoom or YouTube as we’ve been doing for the past few years. (See How to Participate below for details). Due to security concerns, if you log in before the host has set up internet connectivity in Peyton Hall, you may need to wait in the Waiting Room for a few minutes until the host is prepared to admit you into the meeting. You’ll need to unmute yourself to make comments or ask questions. It’s polite, though not required, for you to enable your camera so other participants can see you.
Here’s the anticipated agenda for November’s monthly meeting of the AAAP:
(Times are approximate)
“Meet the Speaker” Dinner Goes Vegan Members are invited to attend the “Meet the Speaker” dinner. Reservation is for 5:45 pm prior to the meeting. Please take note of the new location: Planted Plate 15 Spring Street Princeton, NJ 08540 (609) 356-0845 plantedplatevegan.com
Getting to Peyton Hall The parking lots across the street (Ivy Lane) from Peyton Hall are now construction sites, unavailable for parking. We’ve been advised by the administration of the astrophysics department that we should park in the new enclosed parking garage off Fitzrandolph street and walk around the stadium and athletic fields. Here’s a map of the campus and walking routes from the parking garage to Peyton Hall. The map shows the recently completed East Garage. Not shown is an access road Sweet Gum that connects from Faculty Road to an entrance at the lower left corner of the garage. Stadium Road connects from Fitzrandolph Road to another entrance at the opposite corner (and higher level) of the garage. It’s about a 10-15 minute walk from the parking garage to Peyton Hall.
“The Jewish Calendar: An Ingenious Integration of the Lunar and Solar Cycles”
The Jewish Calendar… The ancient Jews understood well that the sun and the moon were for calendrical reckoning. The notion is so central to Jewish life that it is highlighted in the very first chapter of Genesis: “And God said, ‘Let there be lights in the firmament of the heavens to separate the day from the night; and let them be for signs and for seasons and for days and years’” (1:14). To be sure, the calendar used by the Jews – both then and now – was the standard ancient Near Eastern one developed by the Babylonians, though naturally the Jews adapted the calendar to their own specific needs, with special attention to the Sabbath and the festivals. Prof. Rendsburg will help us explore the fascinating subject of the Jewish calendar, all based on astronomical phenomena, with special attention to the use of lunar months integrated into a solar year.
Gary A. Rendsburg Prof. Rendsburg serves as the Blanche and Irving Laurie Chair in Jewish History and is Distinguished Professor in the Department of Jewish Studies at Rutgers University. His teaching and research focus on ‘all things ancient Israel’ – primarily language and literature, though also history and archaeology. His secondary interests include ancient Egypt, the Dead Sea Scrolls, and the Hebrew manuscript tradition.
Prof. Rendsburg is the author of seven books and more than 200 articles. His most recent book is How the Bible Is Written (Hendrickson, 2019), with particular attention to the use of language to create literature.
In addition, he has produced two series for the Great Courses program, one on ‘The Book of Genesis’ and one on ‘The Dead Sea Scrolls’; plus he lectures regularly for Smithsonian Associates, One Day University, the Biblical Archaeology Society, and other adult education venues.
Prof. Rendsburg has visited all the major archaeological sites of Israel, Egypt, and Jordan, plus he has excavated at Tel Dor and Caesarea. He also has done extensive research on medieval Hebrew manuscripts at leading libraries, including the Bodleian Library in Oxford, the Cambridge University Library, the Vatican Library, Fisher Library in Sydney, and the Library of Congress in Washington.
During his career, Prof. Rendsburg has served as visiting professor or visiting research scholar at the University of Oxford, the University of Cambridge, the University of Sydney, the Hebrew University, Bar-Ilan University, the University of Pennsylvania, UCLA, the Getty Villa, and the Pontifical Biblical Institute (Rome).
Unjournal Club AAAP member and former Program Chair Ira Polans will present “Basic Principles of Celestial Navigation,” and show how to conduct a noon sight; using a sextant to measure the angle between the sun and the horizon at local noon.
How toParticipate Zoom Amateur Astronomers Association of Princeton is inviting you to a scheduled Zoom meeting. Prof. Gary A. Rendsburg Topic: “The Jewish Calendar: An Ingenious Integration of the Lunar and Solar Cycles” Time: Nov. 14, 2023 07:00 PM Eastern Time (US and Canada) Join Zoom Meeting https://us06web.zoom.us/j/86111412467?pwd=BcYgjixdFqRXvhqA82cXoM9QiR3u83.1
AAAP webcast: This month’s AAAP meeting, beginning with Rex’s opening remarks and ending at the beginning of the business meeting, will be webcast live on YouTube and recorded for subsequent public access on AAAP’s YouTube channel. Be aware that your interactions during this segment, including questions to our guest speaker, may be recorded for posterity.
Join YouTube Live to listen to the speaker using the link below –
Dr. Motta is a cardiologist and past president of AAVSO who uses his home-built 32” telescope to image various objects and to study variable stars. He will talk about building his telescope and the observations he makes with it. He would join the meeting via Zoom. Suggested by Michael DiMario.
January 9 2024
Erika Hoffman
Graduate student, University of Maryland ebhoff@umd.edu
Erika will describe her research using high-resolution x-ray spectroscopy to investigate ionized outflows from active galactic nuclei (AGNs). Suggested by Bill Thomas.
February 13 2024
Prof. David John Helfand Columbia University djh@astro.columbia.edu
The Universal Timekeepers: Reconstructing History Atom by Atom By utilizing the basic building blocks of matter as imperturbable little clocks, we are now able to reconstruct in quantitative detail a remarkable range of human and natural events. From detecting art forgeries to dating archeological sites, and from laying out a detailed history of human diet and the Earth’s climate to revealing the events surrounding the origin of life, of the Solar System and of the Universe itself, atoms provide us with a precise chronology from the beginning of time to the moment humans emerge to contemplate such questions.
Copies of Prof. Helfand’s book will be for sale and he’ll be available to sign them.
March 12 2024
TBA
April 9 2024
Eclipse Observations
Since this meeting will take place the day after the Total Solar Eclipse of 08 April 2024, and many members will be out of town or returning from their trips, I’m suggesting that we host an online roundup of eclipse observations, with members (and perhaps others) Zooming in to share their experiences.
May 14 2024
Dr. Tea Temim Research Astronomer, Princeton University Department of Astrophysics
Dr. Temim will describe her research using JWST imagery to study supernova remnants. Suggested by Gene Allen. temim@astro.princeton.edu
June 11 2024
NJ State Museum planetarium’s Bill Murray, and Jacob Hamer, Assistant Curator
AAAP’s traditional annual pilgrimage to the NJ State Museum planetarium in Trenton, where members will experience a presentation and a preview of the planetarium’s latest sky show.
The meeting was convened in Peyton Hall by Astrophotography Chair Michael DiMario at 1930. Following a brief introduction Member Ira Polans introduced speakers Member John Church, PhD, and Member Michael DiMario, PhD. John gave details about the optical design of the Yerkes 40” refractor and Michael spoke about its employment and the discoveries it enabled. The second question session wrapped at 2052 for a ten minute break.
The business meeting convened at 2102 with a reminders of the Lunar South Pole Observation Challenge and the upcoming Annular Solar Eclipse on 10/14. Two significant astronomical events were discussed: the distortion of the tail of Comet Nishimura C/2023P1 by a CME and the Osirus Rex asteroid sample return on 09/25.
Merchandise Chair Rich Sherman reminded us to prepare for the coming cooler weather with AAAP logo attire.
The meeting was adjourned at 2115.
We had 18 attend the speakers online. During the business meeting we had 12 remain online.
Membership currently numbers 201, with 43 having joined in 2023. There have been 95 renewals while 41 have allowed their membership to expire, giving us a 70% retention rate. Submitted by Secretary Gene Allen, whose attendance was only by Zoom due to quarantine.
A recent article in the journal “Nature” piqued my interest about data formats for data coming from microscopic observations. Wearing my Information Technology hat, I read this article and also explored the different data formats in use for Astronomical data.
The article mentioned that there is no one standard for data coming out of Microscopes. Thousands of biological researchers use microscopes made by different manufacturers. Unfortunately each vendor creates data in their own proprietary format. As a result, researchers cannot exchange data with each other.
The importance of data standards becomes noticeable if the recipient cannot view an image I share in an email. We all can read a PDF file or a JPEG based picture. We take these standards for granted, but absent such standards the networking effect would be very feeble. That is the value of a phone network increases if more people can share information (voice or data). We just have to remember the VHS vs. Betamax wars from yesteryears for the video cassettes. One type of video player could not play the other format. Eventually VHS won the battle but lost the war when video cassettes became history in a few years.
A standard called OME (Open Microscopy Environment) is coming to the fore so that one set of observations made by one researcher can be viewed and studied by another in a different Lab or a different country. The key to such a data format is the presence of metadata, which describes the data present in the file, i.e. the specimen observed, the conditions prevailing at the time of observations etc. Increasingly data formats contain the metadata, the actual data, and chunking of data so that the whole set of data need not be transmitted which could overwhelm the networks as well as the resources on devices like cell phones. Like Google maps, more data is requested when the user moves the cursor to a different area or wants to magnify a certain area. The data is transmitted only in chunks on a need basis.
The telescopes and the spectroscopes by comparison to a microscope, are custom built. I am not talking about the backyard telescopes. Instead the Keck telescope in Hawaii or the JWST (James Webb Space Telescope). It is easier to standardize data format for astronomical data than it is for biological data from a microscope.
In the 1970s, the Astronomers came up with the Flexible Image Transport System (FITS) standard when became a widely used data format. It incorporates metadata and binary data in the same file.The FITS standard has several limitations that make it difficult to use for complicated and hierarchical metadata. It is an older standard which was defined when computing and networking resources were at a premium. It needed a change.
The Advanced Scientific Data Format (ASDF) was originally developed in 2015. The format consists of a YAML (Yet Another Markup Language) header optionally followed by one or more binary blocks for containing binary data. This format is not limited to Astronomy, and is being proposed as suitable for much of scientific and engineering data, NASA has adopted ASDF and FITS data formats for JSWT. The upcoming Nancy Grace Roman Space Telescope is slated to be launched in 2026. Although its mirror size is the same as that of the Hubble Space Telescope (HST), its field of view is much larger. It will be used mostly for survey of the skies. ASDF will be the primary data format for this telescope.
To read and process the data, libraries exist for the Python and C++ programming languages. ASDF, like FITS, is only a transport format but not a storage format. Storage formats are different for high performance computing environments. Given that a lot of research gets done after, sometimes long after the data is captured by the telescope, storing and transporting data in a standard format is very important. Data is at the center of new astronomical discoveries. With the launch of more sophisticated telescopes with increasingly complex instruments, and more powerful computing facilities and standard data formats on the Earth, awaiting many more discoveries in the future.
NASA’s Hubble spots a mysterious flash in the middle of nowhere that defies science A bright flash of blue light appearing in the middle of seemingly empty space has scientists confused.The brilliant flash — thought to have burned at about 36,000 degrees Fahrenheit —is a rare explosion…more
-NYT
‘Big Whack’ Formed the Moon and Left Traces Deep in Earth, a Study Suggests Where did the moon come from? The most popular theory says that about 4.5 billion years ago, a Mars-size protoplanet slammed into Earth. Some of the resulting debris, tossed into orbit, coalesced to form the moon….more
-NYT
A chunk of the moon appears to be orbiting near Earth, new study suggests Astronomers have found more evidence that a near-Earth asteroid is an ejected chunk of the moon.The asteroid Kamo’oalewa — a Hawaiian name that means “the oscillating fragment” — is a Ferris-wheel-size rock chunk…more
-phys.org
Salts and organics observed on Ganymede’s surface by NASA’s Juno Data collected by NASA’s Juno mission indicates a briny past may be bubbling to the surface on Jupiter’s largest moon. NASA’s Juno mission has observed mineral salts and organic compounds on the surface of Jupiter’s moon Ganymede…more
-skyandtelescope
Black Hole Rain The planned LISA gravitational-wave detector might discover a shower of hundreds of small black holes falling in galactic centers. At the center of nearly every massive galaxy sits at least one supermassive black hole. These black holes weigh in at millions or even billions of times the mass of the Sun…more
-space.com
Nailing down exoplanet orbits could be key to finding ET. Here’s why The search for extraterrestrial intelligence (SETI) will likely be sped up thanks to new results that narrow down how alien radio signals would drift in frequency as a result of the Doppler shift caused by their home planet’s orbit around its star. A Doppler shift is the lengthening or shortening of the frequency of a signal caused by the motion of the transmitter…more
-space.com
Supervolcano eruption on Pluto hints at hidden ocean beneath the face Although it has been close to a decade since NASA’s New Horizons spacecraft visited Pluto, the dwarf planet continues to reveal itself as a surprisingly complex world. Scientists studying spacecraft data of an unusual crater near a bright, heart-shaped region…more
-NYT
Lucy Mission Set Its Sights on 1 Asteroid. It Found 2 On Wednesday, NASA’s Lucy spacecraft zoomed by its first asteroid target — and scientists on the mission were shocked to discover that the rock, named Dinkinesh, was actually two rocks. The binary consists of a larger, primary asteroid and a smaller “moon” orbiting around it, as seen in images that Lucy captured of the pair…more
-space.com
Supermassive black hole seen spinning ropes of plasma like a cosmic spider Like a monstrous cosmic spider, a distant supermassive black hole is spinning a jet of plasma into a twisted rope and blasting it out at near-light speed. Astronomers witnessed this spectacular sight with a network of radio telescopes, including the RadioAstron space telescope, that are combined to form an Earth-sized…more
-NYT
NASA’s Parker Solar Probe smashes record for fastest human-made object The NASA Parker Solar Probe has become the fastest human-made object ever recorded — again. On Sept. 27, the probe reached a blistering 394,736 mph/ (635,266 km/h) as it swooped close to the sun’s surface, thanks to a little gravity assistance from a close flyby of Venus on Aug. 21…more
by Rex Parker, PhD director@princetonastronomers.org
October 10 Meeting at Peyton Hall on Campus. We will meet once again in person at Peyton Hall for our next monthly meeting. Thanks to Ira and Dave, we’ll also be running a hybrid meeting through Zoom. For information about the guest speakers, please see Victor’s section below. We hope to see you there in person or on Zoom!
Red Sky in Morning, Astronomers Take Warning. Sailors and astronomers alike have witnessed an unwelcome physics experiment over the past summer. Our G-type star, the sun, normally appears white or yellowish, a blending of all the colors it emits. This summer it turned red, as if it were an M-type red star such as those we sometimes observe through telescopes. The cause was huge flaming wildfires in the boreal forests of Canada, with unimaginable volumes of smoke released into the atmosphere and spread by currents across the northern US skies. Combustion of forest biomass produces a complex mixture of carbon-based particles and volatile organic compounds, nitrogen oxides, and other trace minerals. It’s been estimated that over a million tons of smoke particles were released from the fires burning in Quebec alone this summer.
The sun in its red costume as seen from southeast Alaska, July 2023. Photo taken without filters using a Canon Powershot SX70, by RA Parker.
So just why did smoke in the air this summer cause our sun to appear red, even at noon? Of course, you should never look directly at the sun without proper filters even when it’s red! This is a different physics phenomenon than the Rayleigh scattering that explains why the daytime sky is blue and turns red at sunset and sunrise. Rayleigh scattering involves an interaction of air gas molecules with electromagnetic waves, where the molecules act as radiating dipoles whose radiation appears as scattered light. The interaction occurs only when the molecular diameters of gases (particles) are much smaller than the wavelengths of light. The shorter wavelength blue light is scattered much more by this mechanism, which we perceive as a blue sky. When the Sun is lower in the sky the path length is greater, resulting in even more blue scattering, and thus red penetration to our eyes.
However, a very different type of light scattering results when the size range of particulates suspended in air is comparable to the wavelength of light. The diameter of wildfire smoke particles typically ranges from ~0.5 to 1 micrometers, overlapping the wavelength range of red light but greater than blue light. The scattering of light waves by particles of comparable size is known as Mie scattering, after the German physicist Gustav Mie who solved the physics of light scattering and absorption in 1908. Mie derived his solution from the famous Maxwell equations (which few could understand then and even today), where he quantified the scattering of an electromagnetic wave by spheres of defined radii. One feature of Mie scattering is that certain sizes of particles scatter light especially strongly, known as the Mie resonances. Wildfire smoke particles fall into such a resonance, so that Mie scattering dominates and results in a red sun and sky background.
Gustav Mie’s papers were hardly noticed for 50 years, apparently because computers hadn’t been invented yet and the equations were quite difficult! But more recently his works on scattering and absorption have been referenced over 4000 times in astronomy, meteorology, and fluid dynamics. If you are interested in a deeper dive into the story, see this reference: H. Horvath, Journal of Quantitative Spectroscopy & Radiative Transfer 110: 787-799 (2009).
Update: Lunar South Pole Observing Challenge. The members’ observing challenge which I presented last winter is still open, as we’ve had no reports of a successful observation yet. The challenge is to observe with your telescope (and image, if possible) the extreme southern polar region of the moon around Shackleton Crater. This region is hugely important to the future of lunar exploration for many reasons, with data from orbiting instruments strongly indicating the presence of water ice in permanently shadowed regions of Shackleton and nearby south pole craters.
It may sound simple, but observing the moon’s south pole is quite difficult. The trick for earthly astronomers is to observe the moon at precisely the right time in the monthly lunar libration sequence when the extreme south pole craters become visible, perhaps one night a month. This is described further in Sky & Telescope, March 2022, “Meet Shackleton Crater: Future Moon Landing Site”. Observing the south pole from an off-our-planet vantage point is another way to do it. Indeed, this happened twice in the past couple of months! So, here are two challenge “winners”: the Indian Space Research Organization (ISRO) Chandrayaan 3 lunar lander, and NASA’s Lunar Reconnaissance Orbiter (LRO) together with the Korea Aerospace Research Institute (KARI)’s Korea Pathfinder Lunar Orbiter (KPLO) mission, also known as Danuri.
On Aug 23, ISRO’s Chandrayaan 3 became the first spacecraft to land near the lunar south pole. The Chandrayaan-3 mission is unfolding at a time when the US and China are planning future crewed missions to the region. NASA aims to land astronauts and eventually build a base near the lunar south pole in perhaps 2026 on its Artemis 3 mission and beyond. This is essential to developing the Lunar Gateway, the first planned extraterrestrial space station in lunar orbit, eventually providing a path to Mars and beyond.
Last week NASA released the first-ever detailed photograph of the permanently shadowed Shackleton Crater located very close to the south pole last week. This photo was an innovative mosaic of data from two sources: the Lunar Reconnaissance Orbiter Camera (LROC) and a new NASA-developed instrument called ShadowCam aboard KARI’s Danuri orbiter. The super high resolution of LROC is half-a-meter per pixel, but requires bright illumination such as Shackleton Crater’s rim. ShadowCam, about 200-times more light sensitive than LROC, was able to reveal details in the permanently shaded interior of the crater. The resulting composite picture shows the 2 mile deep and 12 mile wide Shackleton Crater as never before seen by human eyes. For more info, see this link: NASA shares unprecedented view of moon’s south pole region (axios.com)
The first detailed image of Shackleton Crater at the south pole of the moon, in a mosaic photo from two lunar orbiters. See the text above for explanation. Credit: NASA
The October, 2023 meeting of the AAAP will take place in Peyton Hall on Tuesday, October 10th at 7:30 PM. As usual, the meeting is open to AAAP members and the public. Participants can join the meeting in-person at Peyton Hall or log in to the Zoom session as early as 7:00 pm to chat informally before the meeting begins. This evening’s guest speakers are AAAP members John Church and Michael DiMario. John will discuss the optical design of the famed Yerkes refractor, still the largest refracting telescope in existence. Michael will discuss the history of the observatory from its conception in 1892 to its recent revitalization.
Options for Attending the October Meeting
You may choose to attend the meeting in person or participate via Zoom or YouTube as we’ve been doing for the past few years. (See How to Participate below for details). Due to security concerns, if you log in before the host has set up internet connectivity in Peyton Hall, you may need to wait in the Waiting Room for a few minutes until the host is prepared to admit you into the meeting. You’ll need to unmute yourself to make comments or ask questions. It’s polite, though not required, for you to enable your camera so other participants can see you.
Here’s the anticipated agenda for October’s monthly meeting of the AAAP:
(Times are approximate)
“Meet the Speakers” at Winberie’s Members are invited to attend the “Meet the Speaker” dinner at Winberie’s Bar and Restaurant before the meeting. Our reservation is for 5:45 pm. Please contact Acting Program Chair Ira Polans if you plan to attend.
Winberie’s Bar and Restaurant 1 Palmer Square E Princeton, NJ (609) 921-0700 princeton.winberies.com
Ira Polans, ipolans@princetonastronomy.org
Getting to Peyton Hall The parking lots across the street (Ivy Lane) from Peyton Hall are now construction sites, unavailable for parking. We’ve been advised by the administration of the astrophysics department that we should park in the new enclosed parking garage off Fitzrandolph street and walk around the stadium and athletic fields. Here’s a map of the campus and walking routes from the parking garage to Peyton Hall. The map shows the recently completed East Garage. Not shown is an access road Sweet Gum that connects from Faculty Road to an entrance at the lower left corner of the garage. Stadium Road connects from Fitzrandolph Road to another entrance at the opposite corner (and higher level) of the garage. It’s about a 10-15 minute walk from the parking garage to Peyton Hall.
Optical Design and Characteristics of the Yerkes 40-inch Refractor John will discuss the paths taken and not taken with the famed Yerkes 40-inch refractor; its basic optical design and what is known about the refractive indices and radii of its crown and flint elements. Building on a 1982 article he wrote for Sky and Telescope, Dr. Church will cover the various aberrations that can be deduced from the available data as well as those that would result from alternate radii that might have been used. He will also discuss how the objective’s performance would be affected by minor changes in the spacing of the lens elements. He’ll conclude by contrasting the design philosophies between the Yerkes Alvan Clark refractor and AAAP’s own Hastings 6 ¼ inch refractor.
John Church, PhD A native of Richmond, John Church graduated from the University of Virginia with a bachelor’s degree in chemistry and then earned M.S. and Ph.D. degrees from Lawrence University in Appleton, Wisconsin. His thesis work was concerned with the reaction of crystalline carbohydrate derivatives with oxygen under relatively mild conditions. He spent his career in research and development with American Can Company at their Corporate R&D laboratory in Princeton and then with Colgate-Palmolive at their Corporate Research Center in Piscataway. He is now retired.
John is the author of sixteen scientific, historical, and technical publications, including several on the optics of refracting telescopes as well as one on close conjunctions of Jupiter and Saturn. He holds ten U.S. patents and is the author of a book chapter on the chemistry of bleach. He has written three books and edited several others. One of his Sky & Telescope articles traced the history of the 6 ¼ inch Hastings-Byrne refractor now installed in our observatory in Washington Crossing State Park, which he and many others helped build in the late 1970’s.
John has served as Assistant Director, Director, and Program Chair of the AAAP. This September will mark his 53rd year as a club member. His civic activities include presently serving on the West Windsor Township Zoning Board of Adjustment. He is married and has three children and six grandchildren.
The History and Revitalization of Yerkes Observatory Mike will present the early history of the Yerkes Observatory from its construction in 1892 through two revitalizations in 1932 and 2020. He will describe the technologies used at its beginning and those still in use today. He’ll recount the use of the Edison dynamo the 15 ton observatory floor collapse 1n 1897, and give an overview of the present-day telescopes in three of the observatory’s domes.
Michael DiMario, PhD Dr. DiMario is the founder and CEO of Astrum Systems, a global consulting venture focused on employing systems engineering methodologies in early research and development. Dr. DiMario holds an MBA in Management of Technology, an MS in Computer Engineering, and a PhD in Systems Engineering. He has completed significant course work in Space Science. Michael’s corporate career began at General Electric Medical. He served in several executive engineering roles at Bell Laboratories/Lucent Technologies, and at Lockheed Martin, from which he recently retired.
Dr. DiMario also operates a blog highlighting large university-based observatories including solar and radio-frequency telescopes. He has been granted five patents, is credited with numerous trade secrets, published a book and contributed a book chapter on systems engineering, and has written more than forty peer-reviewed papers on quantum magnetometry, systems engineering, and quality management. He has been interviewed by magazines including Wired, GPS World, Sifted, and Financial Times. He co-chairs the INCOSE Early Systems Engineering and Research Working Group, and leads AAAP’s astroimaging Special Interest Group. He holds an amateur radio Extra class license, call sign K2MJD.
How toParticipate Zoom Amateur Astronomers Association of Princeton is inviting you to a scheduled Zoom meeting. AAAP-October 2023 Meeting-John Church & Michael DiMario-The Yerkes Observatory and the 40-inch Refractor
Topic: AAAP-October 2023 Meeting-John Church & Michael DiMario-The Yerkes Observatory and the 40-inch Refractor Time: Oct. 10, 2023 07:00 PM Eastern Time (US and Canada) Join Zoom Meeting https://us06web.zoom.us/j/85600238601?pwd=rLUESl9xxZVopM9HvX3WhIUeamZqK4.1 Meeting ID: 856 0023 8601 Passcode: 559172
AAAP webcast: This month’s AAAP meeting, beginning with Rex’s opening remarks and ending at the beginning of the business meeting, will be webcast live on YouTube and recorded for subsequent public access on AAAP’s YouTube channel. Be aware that your interactions during this segment, including questions to our guest speaker, may be recorded for posterity.
Join YouTube Live to listen to the speaker using the link below –
Dr. Gary Rendsburg Distinguished Professor of Jewish Studies and History at Rutgers
Prof. Rendsburg will talk about “The Jewish Calendar,” with emphasis on its astronomical connections to lunar months, intercalated month to adjust to the solar year, festival days, and new moon observances. Suggested by Ira Polans.
Also, AAAP member Peter Wraight will show and discuss his 3D printed binoscope designs for which he won two awards for Mechanical Design at last year’s Stellafane convention.
December 12, 2023
Dr. Mario Motta
Dr. Motta is a cardiologist and past president of AAVSO who uses his home-built 32” telescope to image various objects and to study variable stars. He will talk about building his telescope and the observations he makes with it. He would join the meeting via Zoom. Suggested by Michael DiMario.
January 9 2024
Erika Hoffman
Graduate student, University of Maryland ebhoff@umd.edu
Erika will describe her research using high-resolution x-ray spectroscopy to investigate ionized outflows from active galactic nuclei (AGNs). Suggested by Bill Thomas.
February 13 2024
TBA
March 12 2024
TBA
April 9 2024
Eclipse Observations
Since this meeting will take place the day after the Total Solar Eclipse of 08 April 2024, and many members will be out of town or returning from their trips, I’m suggesting that we host an online roundup of eclipse observations, with members (and perhaps others) Zooming in to share their experiences.
May 14 2024
Dr. Tea Temim Research Astronomer, Princeton University Department of Astrophysics
Dr. Temim will describe her research using JWST imagery to study supernova remnants. Suggested by Gene Allen. temim@astro.princeton.edu
June 11 2024
NJ State Museum planetarium’s Bill Murray, and Jacob Hamer, Assistant Curator
AAAP’s traditional annual pilgrimage to the NJ State Museum planetarium in Trenton, where members will experience a presentation and a preview of the planetarium’s latest sky show.
The Out-of-Towners Just a note to let you know that Director Rex Parker and Program Chair Victor Davis will be out of the country in October, visiting different hemispheres. Michael DiMario has agreed to be Acting Director for the October meeting, and Ira Polans has agreed to be Acting Program Chair. Many thanks to each of them for stepping up so Rex and I can go gallivanting without worries.
“Exoplanets: Science and Science Fiction” Now a Book!
Princeton astrophysicist Prof. Joshua N. Winn, AAAP’s guest speaker last December, has written a book based closely on his presentation to us. The book, “The Little Book of Exoplanets,” is written for the general public. The book describes what we know about exoplanets and how we know what we know about them.
The meeting was convened in Peyton Hall by Director Rex Parker at 1930. His announcements included crediting India’s Chandraayan 3 lander with capturing the best images for his Lunar South Pole Observation Challenge, Member Dr. Bob Vanderbei’s excellent solar image using only the smoke from the Canadian wildfires instead of a filter, Rex’s plotting of the light curve as the M101 supernova has aged since its appearance on May 19. It has also turned much redder, as seen in both the images at the observatory on his heavily-attended Team 5 Public Night and in the data he collected for the light curve.
At 1943 Program Chair Victor Davis introduced Speaker Dr. Suzanne Staggs, Professor of Physics at Princeton University. Her lecture was entitled “Looking Backward with the CMB” and dealt with the discovery and the subsequent detailing of our knowledge of the Cosmic Microwave Background. After the talk, a few questions invoked very long answers.
The business meeting convened at 2120 with Member Peter Wraight describing of another impressive set of 3D printed right angle binoculars that he has built. These include a bracket for a smartphone running a planetarium program that is masked to match the 6.5 degree visual field. With a collimated laser pointer they serve as a simple but very effective non-electronic finder for a larger telescope.
Member Tom Swords was checking out a recently refurbished and collimated scope. When he used SkySafari to aim it at M39, there was a white streak across it because he had “show comets” turned on and comet C/2023 E1 Atlas was passing by. He had accidentally encountered and was able to image a comet!
The many Outreach events that have been requested were recapped again by Outreach Chair Bill Murray. While they have not been entered into the AAAP online calendar, they have previously been emailed to all members. He has adequate volunteers for most of the events, but members are still welcome to add on.
Rex wrapped up by sharing a special visit he managed to arrange to see the 20 inch refractor in the Van Vleck Observatory on the campus of Wesleyan University in Connecticut.
The meeting was adjourned at 2150.
We had 33 attend the speaker in person and 30 online. During the business meeting we had 17 remain in person and 18 continued with us online.
Membership currently numbers 205, with 40 having joined in 2023. There have been 80 renewals while 30 have allowed their membership to expire, giving us a 73% retention rate.
Amateur Astronomers Association of Princeton 