Welcome to the fifteenth of our monthly newsletters. We will be bringing this bulletin to you around the middle of each month to keep you informed about Planetarium and Friends news, as well as happenings in the world of astronomy and events in our area related to science education. Visit the website for more news updates and a list of our articles.

Vernal Equinox March 20

This year, the Sun crossed the celestial equator heading north on March 20 at 11:33 AM EDT, which now marks the beginning of astronomical spring, the first day of Spring in the Northern Hemisphere. Sunday was one of two days each year with roughly equal amounts of daylight and nighttime. Assuming standard refraction, sunrise should be at 07:12 AM EDT while sunset will be at 07:20 PM EDT giving us 12 hours and 8 minutes of daylight. The few minutes of extra daylight are due to our defining of sunrise and sunset as occurring when the upper edge of the Sun is on the horizon. Contributed by Jennifer Lynn Bartlett.

Eugene Parker, astrophysicist namesake of NASA solar probe, dies at 94
The astrophysicist who predicted the existence of the solar wind died on March 15. Parker was renowned in the field of solar physics. His theoretical prediction of the existence of the solar wind, charged particles streaming from the Sun that interact with our atmosphere and create the Aurorae, met with widespread skepticism, but was confirmed in 1962 in a mission to Venus.

James Webb Space Telescope Commissioning

The James Webb Space Telescope is currently over 2 months into commissioning after a December 25, 2021 launch from French Guiana. Commissioning efforts are based at the Space Telescope Institute (STScI) in Baltimore, MD. The team is currently aligning [see next item] the 18 segmented primary mirror to perform observations of targets. Webb has four instruments onboard that will be utilized to capture data. Near Infrared Camera (NIRCam) instrument was utilized for the image shown here, demonstrating the capability to collect light from celestial objects and identify the same target in each of the 18 primary mirror segments. The first scientific images will be public in the summer after completion of the primary mirror alignment. Contributed by Elaine Stewart.

 

Focussing of the James Webb Space Telescope Exceeds Expectations

Credit: NASA/ESA/CSA/STSCI

The image shows “a generic, anonymous star” used to test the focussing of the Webb Telescope’s mirrors. The spikes are the diffraction pattern created by the mirror geometry. The telescope achieved a diffraction limited infrared (2 μm) image, meaning that the image was a sharp as physically possible, a stunning success for the project.

Mary Fairfax Greig Somerville (1780-1872)

In 1835, Scottish-born Mary Somerville was one of first two women elected to the Royal Astronomical Society; the other was Caroline Herschel. At a time when women’s education was not valued, Somerville was accomplished in mathematics, astronomy, and geography. In the 1842 edition of her book, The connection of the physical sciences, she wrote about the possibility of the orbit of Uranus being perturbed by another planet, which inspired John Adams (1819-1892) to begin calculating the possible position of such an unseen planet. She also assisted Augusta Ada King (1815-1852), countess of Lovelace, study mathematics. Contributed by Jennifer Lynn Bartlett.

Telescopes, Part 5 – X-Ray Telescopes

The Chandra X-ray Observatory. Credit: NASA/CXC & J.Vaughan

Not all telescopes gather and focus waves in the visible part of the electromagnetic spectrum. Radio telescopes (described in a previous article) are concerned with long radio waves. A different kind of instrument, the X-ray telescope, works with short wavelengths on the other end of the spectrum. X-ray scopes are well suited to examining the hot matter around exploded stars and black holes. These scopes are very different from traditional optical instruments, however. Since Earth’s atmosphere blocks X-rays, they need to operate in outer space. X-ray scopes also have a very different mirror arrangement than a typical optical telescope. High energy X-rays would go right through a standard telescope mirror, so in an X-ray scope the mirrors are set almost parallel to the incoming waves. The X-rays graze, or ricochet off the mirrors, and can then be focused onto a detector. The data gathered from the recorded X-rays is assembled into high resolution images. The Chandra X-ray Observatory, currently the most powerful X-ray telescope, has been operating in Earth orbit since 1999. Contributed by Kathi Overton.

Arlington 55+ Program March 31 @ 11 AM EDT Virtual

Friends’ President Jennifer Bartlett will present “Does Anyone Know What Day It Is” on March 31^st at 11 AM EDT to participants in Arlington’s 55+ Programs. She will discuss the astronomical basis of the calendar, how ancient cultures organized their concepts of times, and dating of Ramadan, Passover, and Easter. To receive the meeting link for this free, virtual event, qualified members must register through Arlington County Department of Parks and Recreation. If you do not hold a 55+ Pass, you might be interested in the recording of “The Moon and Its Influence on Calendar Systems,” a conversation between Jennifer and Teresa Wilson in April 2020 that also touched on the concept of a supermoon. The video is available on the Friends Vimeo site. Contributed by Jennifer Lynn Bartlett.

Edited by Lee Phillips and anonymous assistants who are responsible for any errors.