The monthly general membership meeting of the Cuyahoga Astronomical Association will take place March 9, 2020 from 7:30 to 9:00 p.m. CAA Member and Vice President Tim Campbell will present his talk, “Mauna Kea: Telescopes above the Clouds!” — his visit to Hawaii’s Mauna Kea mountaintop observatories (MKO). Several major telescopes are located there at 14,000 feet above sea level. Mauna Kea is one of the most important sites in Earth-based astronomy and Campbell will take attendees on a detailed tour!
The CAA’s monthly meetings are held on the second Monday of every month except December at 7:30 p.m. in the Cleveland Metroparks’ Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio. Meeting programs are open to the public. Following the presentation and a brief social break, the club will conduct its membership business meeting.
Astronomers using ESO’s SPHERE instrument at the Very Large Telescope (VLT) have revealed that the asteroid Hygiea could be classified as a dwarf planet. The object is the fourth largest in the asteroid belt after Ceres, Vesta and Pallas. For the first time, astronomers have observed Hygiea in sufficiently high resolution to study its surface and determine its shape and size. They found that Hygiea is spherical, potentially taking the crown from Ceres as the smallest dwarf planet in the Solar System.
As an object in the main asteroid belt, Hygiea satisfies right away three of the four requirements to be classified as a dwarf planet: it orbits around the Sun, it is not a moon and, unlike a planet, it has not cleared the neighborhood around its orbit. The final requirement is that it has enough mass for its own gravity to pull it into a roughly spherical shape. This is what VLT observations have now revealed about Hygiea.
“Thanks to the unique capability of the SPHERE instrument on the VLT, which is one of the most powerful imaging systems in the world, we could resolve Hygiea’s shape, which turns out to be nearly spherical,” says lead researcher Pierre Vernazza from the Laboratoire d’Astrophysique de Marseille in France. “Thanks to these images, Hygiea may be reclassified as a dwarf planet, so far the smallest in the Solar System.”
The team also used the SPHERE observations to constrain Hygiea’s size, putting its diameter at just over 430 km. Pluto, the most famous of dwarf planets, has a diameter close to 2,400 km, while Ceres is close to 950 km in size.
Surprisingly, the observations also revealed that Hygiea lacks the very large impact crater that scientists expected to see on its surface, the team report in the study published today in Nature Astronomy. Hygiea is the main member of one of the largest asteroid families, with close to 7,000 members that all originated from the same parent body. Astronomers expected the event that led to the formation of this numerous family to have left a large, deep mark on Hygiea.
“This result came as a real surprise as we were expecting the presence of a large impact basin, as is the case on Vesta,” says Vernazza. Although the astronomers observed Hygiea’s surface with a 95 percent coverage, they could only identify two unambiguous craters. “Neither of these two craters could have been caused by the impact that originated the Hygiea family of asteroids whose volume is comparable to that of a 100 km-sized object. They are too small,” explains study co-author Miroslav Brož of the Astronomical Institute of Charles University in Prague, Czech Republic.
The team decided to investigate further. Using numerical simulations, they deduced that Hygiea’s spherical shape and large family of asteroids are likely the result of a major head-on collision with a large projectile of diameter between 75 and 150 km. Their simulations show this violent impact, thought to have occurred about 2 billion years ago, completely shattered the parent body. Once the left-over pieces reassembled, they gave Hygiea its round shape and thousands of companion asteroids. “Such a collision between two large bodies in the asteroid belt is unique in the last 3–4 billion years,” says Pavel Ševeček, a PhD student at the Astronomical Institute of Charles University who also participated in the study.
Studying asteroids in detail has been possible thanks not only to advances in numerical computation, but also to more powerful telescopes. “Thanks to the VLT and the new generation adaptive-optics instrument SPHERE, we are now imaging main belt asteroids with unprecedented resolution, closing the gap between Earth-based and interplanetary mission observations,” Vernazza concludes.
The September 2019 meeting of the Cuyahoga Astronomical Association (CAA) will feature a presentation by Dr. Stacy McGaugh, Case Western University Professor and Chair of Astronomy. In “Dark Matter and Gravity in the Universe,” Dr. McGaugh will discuss his work on the search for dark matter and the possibility that it does not exist and we simply do not understand gravity! He has co-authored several papers outlining this controversial view.
The CAA’s monthly meetings are held on the second Monday of every month except December at 7:30 p.m. in the Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio, in the Cleveland Metroparks. Meeting programs are open to the public. Following the presentation and a brief social break, the club will conduct its membership business meeting.
A nighttime visit to Lake Erie’s Marblehead Lighthouse provided the perfect opportunity for the Cuyahoga Astronomical Association’s Alan Studt to create this beautiful image. This nightscape isn’t a simple, single-exposure image as done in the old film camera days.
Here’s what went into making this picture:
Shot an approx. 22-minute star trail between 11:30 and Midnight (100 – 13 second shots at ISO 3200).
Edit out dozens of airplanes – probably all but a handful of the shots had multiple planes flying by.
Foreground is made of 45 images median stacked equaling about a nine-minute exposure.
Tamron 15-30mm @ 15mm, f /2.8
Post done in Sequator, StarTrails.exe, Lightroom, and Photoshop
“Beautiful evening!” says Studt. We agree, and thanks for sharing!
The Cuyahoga Astronomical Association (CAA) was well-represented this year at the annual Lakewood Solstice Celebration held on the shores of Lake Erie. CAA members brought 11 telescopes to help support a successful annual Summer Solstice program at Lakewood City Park.
Lakewood Park features an amphitheater-like Solstice Steps facility where visitors are able to view the Great Lake. The evening event draws thousands and boasts food, music, activities and, thanks to the CAA, safe solar viewing and after-sunset astronomy.
Attendees enjoyed clear, sunny skies for most of the day right up until just before sunset. Safe solar viewing was offered through a variety of telescopes and filters though, because Sun was at Solar Minimum, there wasn’t much to see on old Sol’s face.
A group of clouds moved across the Lake Erie horizon from the northwest covering the Sun and obscuring Mars and Mercury, which also should have been visible at sunset.
After sunset, however, Jupiter rose above the trees in the east, providing an opportunity to show visitors Jupiter and a few of his Galilean Moons.
CAA member Jay Reynolds again organized and coordinated the Solstice astronomy program with the city of Lakewood. Reynolds passed along compliments from the city for the timely and organized manner in which members arrived, unloaded, and kept the flow going as members set up their telescope systems.
Lakewood city officials and staff welcomed and supported CAA as part of their annual event. Lakewood Mayor Mike Summers and his wife, expressed how much they enjoy coming to the event and this (telescopes) was their favorite part!
The Lakewood Solstice Celebration is one of several public events in which CAA members provide astronomy outreach programming. “It’s what we do.”
This report by CAA President William Murmann and others.
Come see deep-sky objects, planets, and the Moon up close using the Cuyahoga Astronomical Association’s (CAA) telescopes, from 9:00 to 11:00 PM, Saturday, June 8.
The CAA Observatory will be open for public viewing, and members will be available to answer your questions. Activities and/or displays will be set up inside the barn for further interest on cloudy nights. Given clear enough skies, visitors may view Earth’s Moon, planet Jupiter, and star clusters through a variety of member-owned telescopes.
This is an outdoor program so attendees should dress appropriately for conditions; use of insect repellent is also recommended.
The May 2019 general membership meeting will feature a program entitled, “How to find Your Way Around the Summer Sky” to be presented by club member Gary Kader; he is director of the Burrell Memorial Observatory at Baldwin Wallace University, Berea. Bring the family and your curiosity; copies of Sky and Telescope magazine star maps will be provided.
The CAA’s monthly meetings are held on the second Monday of every month (except December) at 7:30 PM at the Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio, in the Cleveland Metroparks. Meeting programs are open to the public. Following the presentation and a brief social break, the club will conduct its membership business meeting.