Can the Milky Way Cast a Shadow?

Stories of the Milky Way casting a shadow are common but details are elusive. Whenever someone wants to brag about the great dark skies they experienced they often trot out the “it was so dark you could see your shadow by the light of the Milky Way” line. Asking follow-up questions results in repetition and hand-waving.

But could it be true? Is it possible? After all, the Milky Way is large, diffuse, low contrast, and faint. The sun and moon cast shadows. Bright point sources cast shadows. It’s even said that Venus or Jupiter can cast shadows. Can the huge Milky Way, spread across 90 degrees of sky (or more), cast a shadow? In this talk, we move beyond hearsay, legend, and myth and attempt to nail down some facts and experimental results...

Selecting Camera Lenses for Astrophotography, and their use in Narrowband Imaging

Telescopes for astrophotography can be large and heavy instruments, costing thousands of dollars. For those who own DSLR cameras, there are a wide selection of available lenses that make an excellent lightweight, low cost, and easy to use platform for starting in astrophotography. We will look at some advantages (and disadvantages) of using camera lenses when photographing the night sky and examine characteristics of lenses ideally suited for astrophotography. In the second half of the presentation, we will take an introductory look at using narrowband filters for astrophotography, with emphasis on wide-field astrophotography...

Computational Imaging, One Photon at a Time

Single-photon avalanche diodes (SPADs) are an emerging sensor technology capable of detecting and time-tagging individual photons with picosecond precision. Despite (or perhaps, due to) these capabilities, SPADs are considered specialized devices suitable only for photon-starved scenarios, and restricted to a limited set of niche applications. This raises the following questions: Can SPADs operate not just in low light, but in bright scenes as well? Can SPADs be used not just with precisely controlled active light sources such as pulsed lasers, but under passive, uncontrolled illumination like cellphone or machine vision cameras?

I will describe our recent work on designing computational imaging techniques that (a) enable single-photon...

Science or Spycraft? How Astronomers Helped Conquer in the Age of Discovery

In a modern world whose immediate history remains informed by the Cold War, it is easy for us to see the ways in which science and geopolitics intermingle. It is no secret, for example, that the rockets that power our modern space missions are products of Cold War weapons programs, nor is it a secret that the Apollo program was itself a direct response to the Soviet Union’s own triumphs in space exploration. Just as one cannot speak of the Cold War without conjuring the specter of nuclear weapons, one likewise cannot speak of the Cold War without remembering an era when espionage and spycraft came fully into the modern age. But espionage and the guarding of scientific secrets is not unique to modernity...

Theory and Observation in the Pseudo-Annular Eclipse reported near Vienna on 17 June 1433

This talk analyzes a solar eclipse that is described as annular, but that other reports and modern calculations show to have been very total. I explore the reasons for this odd state of affairs, since most eclipse observers are impressed by the darkness, not what’s happening immediately around the Sun. I argue that the report comes from a theoretically sophisticated observer with access to a 14th c. annular eclipse report that shaped his observation, which was then used to refute the concentric-sphere astronomy of al-Bitruji, an influential 12-13th century Arab astronomer.

Michael H...

Teaching Astronomy and Nineteenth-century American Catholic Higher Education – a talk by Dana Freiburger

Pretend it is 1815 and you are a student at Georgetown College in Washington, D.C., could you, with the aid of a terrestrial globe, determine the latitude and longitude of Washington City? Or maybe the more taxing problem to find the time of the sun’s rising and setting, and the length of the day and night at any place? These and over a hundred other problems awaited you in an 1812 book on the use of the globes and practical astronomy employed at this Jesuit college founded in 1789. Written by the Irish-born Jesuit James Wallace, this volume is one example of how the sciences like astronomy enjoyed a confirmed place in American Catholic colleges in the nineteenth century...

The Mysterious Radiation Field in the Milky Way (and Other Galactic Surprises)

Our Milky Way Galaxy is an “island” of stars, interstellar gas, and dark matter in the vast expanses of intergalactic space. In this talk, I will focus on the interstellar (mostly hydrogen) gas. This gas fills the space between the stars, and some fraction of it is ionized: radiation from the stars has enough energy to remove the electron from the proton. By studying the resulting emission lines from this gas with the Wisconsin H-alpha Mapper, we have discovered that the central parts of the Milky Way are permeated by an unusual radiation field. I describe how we ended up making the discovery and why it is significant...

Curiosity Paving the Way for Perseverance

Understanding the past habitable conditions on Mars is a primary scientific driver for NASA’s Curiosity rover. During the last eight years, Curiosity has traversed across diverse terrain within Gale crater and drilled the martian surface over two dozen times. Dr. Williams will provide an update on the latest scientific findings and share spectacular snapshots from along the rover’s journey. In addition, she will present an overview of NASA’s next robotic mission to Mars, Perseverance, which will land at Jezero crater in February 2021. 

Rebecca M. E. Williams is a planetary geologist who studies the history of water on Mars through orbiter and rover observations in conjunction with field-based analog studies on Earth...

MAS’s annual telescope clinic is a chance for people in the Madison area to get their questions answered about telescopes and binoculars. It may also help you with some ideas for the gift-giving season.

Do you have an old telescope that’s gathering dust because you don’t know how to use it?Or are you looking to buy a new one? Whatever the case, join us Friday online and learn something. MAS members will be on hand to answer your questions about your existing telescope or give you ideas for your next purchase.

The December meeting will be a virtual event, hosted with Zoom. Members will receive an email with a link and instructions to join a day or two before the event.

This month we are opening the virtual meeting up to non-MAS members who may want to attend the meeting...

Whispers from the Universe: Astronomy with Gravitational Waves

Dr. Brady will talk about the generation of gravitational waves by colliding black holes and neutron stars, and how they are measured here on Earth using the LIGO detectors. He will tell the story of the first detection of gravitational waves in 2015, for which the Nobel Prize was awarded in 2017, through to the exciting observations that are becoming almost routine.

Patrick Brady received his B.Sc. from University College Dublin in 1988 and a Ph.D. in Physics from the University of Alberta in 1994 where he studied with Werner Israel. He has held research positions at the University of Newcastle-upon-Tyne, Caltech, University of California, Santa Barbara...