Southern Maine Astronomers
7 July, 2022 7:00 p.m.
Attending were members David Gay, Kevin, Kane, Russell Pinizzotto, Greg Thorup, Ron
Thompson, Paul Schumann, Greg Shanos, Jack Gelfand, David Manchester, Al DiSabatino, John
O’Donnell, Jon Wallace, Craig Snapp, Mike Efron, Paul Howell, Owen Buck, Jeff Van Fleet, Ted
Hebert, Scott Lovejoy, Chris Parent, Mike Mack, Joe Long, Dana Hutchins, Carol Alcott, Rob
Burgess and Maame Andoh and guests Jack Madden and our speaker, Stella Ocker.
Reports from Club Members:
The meeting began with club president, Rob Burgess’s Report of the club’s growth. Rob
welcomed six new members, and the club is now close to having 80 members. Moreover, the
club has 17 female members, a far cry from its earlier single digits. It’s clear that SMA is
diversifying its membership, and we hope for increased representation in the future.
Russ Pinizzotto informed members that he had imaged a few more nebulae and clusters in the
Herschel 400 Catalog, and has 20 more objects left. Russ is now, in a few years, nearing the end
of a challenge that many take a decade to complete; a fantastic achievement. He also imaged
Rob reported he and a friend tried to catch all five planets (aligned in order) and the moon at
dawn on June 24 th from Winslow Park in Freeport but couldn’t locate Mercury in the early
morning glare. John O’Donnell stated he also caught the whole alignment from his home in
Greg Shanos reported that he recently imaged Mercury from his home in Sarasota, FL. Rob
asked Greg to send his images along so they could be shared.
Greg Thorup informed the group that he recently camped on Cupsuptic Lake in northwest
Maine and had one of his best views ever of the Milky Way.
Finally, Ara Jerahian, Dana Hastings, and Rob Burgess met with Sarah Kirn, a NASA
Representative at the Gulf of Maine Research Institute. Sarah focuses on Citizen Science
opportunities. Through this connection it is hoped that SMA members will have opportunities
to become involved in Citizen Science, and meaningfully contribute to NASA’s research.
Finally, Rob reminded everyone of the Club’s “Second Saturday” Star Party at Neptune Drive on
July 9th, from 8 - 10 pm. More volunteers are needed, especially those who feel comfortable
using a telescope and laser pointer. However, all are welcome so please show up and enjoy.
Troy Bennett, the southern Maine photojournalist for the Bangor Daily News plans to attend to
cover the event for the paper. He also noted there would be no club meeting in August – get
out and observe!
On behalf of the club recognized Ron Thompson, former Treasurer and longtime member of
SMA’s Board of Directors. The Club nominated Ron for the Astronomical Society of the Pacific’s
Las Cumbres Volunteer Outreach Award. Although Ron was not selected it in no way
diminished his extraordinary outreach efforts on behalf of SMA and the southern Maine
community. Rob highlighted Ron’s efforts that included handling the club’s books as Treasurer,
membership renewals, tax filings, liaising with the AL and NSN as well as performing frequent
outreach to students in the Cape Elizabeth school system, through Space Day Maine and at club
star parties over the years. Perhaps most significant was Ron's representation of SMA with
Cornerstones of Science’s Library Telescope Program. According to Cornerstone’s Executive
Director Cindy Randall over the last decade of volunteer work Ron logged nearly 4,400
volunteer hours retrofitting telescopes for library use, and trained almost 200 librarians on how
to use the telescope. Thanks to his dedication, there are now telescopes in 22 states and in four
dozen Maine libraries in large part due to Ron’s efforts Rob thanked Ron on behalf of the club
for his extraordinary commitment, dedication and enthusiasm. His will be the standard against
which future volunteer efforts will be measured.
Speaker and Presentation:
Our speaker was Stella Ocker, a Phd Candidate in Astronomy from Cornell University. Ocker has
a Bachelor of Science in Physics from Oberlin College. She studies radio wave propagation in
interstellar space, the Milky Way galaxy and other galaxies, and also joined the Voyager team
as a Guest Investigator. Her presentation was on her research on the conditions and
environments of interstellar space.
Ocker began her talk by acknowledging notable individuals who had aided her research on
interstellar space. These include Don Gurnett and Bill Kurth, the Voyager Principal Investigators,
Jim Cordes and Shami Chatterjee, her research advisors, and Linda Spilker and Suzy Dodd, the
Voyager project managers.
The story of the Voyagers begins in the 20th century. Voyagers1 and 2 were launched within a
few weeks of each other in 1977. While both headed to Jupiter and Saturn, to provide close-up
views from fly-bys, thereafter their trajectories deviated: Voyager 2 continuing on along the
plane of the Solar System to pass Uranus and Neptune, while Voyage 1 departed at an oblique
angle. Both entered the Interstellar Medium (ISM) in the 2010’s. The instruments currently
operating on the Voyagers are the cosmic ray subsystem - meant to monitor high energy
particles - the magnetometer, low energy charged particle instrument, the plasma wave
subsystem, and the plasma spectrometer (only on Voyager 2). These instruments help the
spacecraft study different properties of plasma, which is essentially electrically charged gas.
Plasma is the main form of matter in the ISM, so analyzing it is important for understanding the
Ocker began by explaining the way in which the ISM interacts with our solar system. First, as
the sun moves through space, conventional understanding was that it generates an upstream
shock wave known as the bow shock. Also, the sun constantly dispatches material known as the
solar wind, which creates a protective pocket around the planets called the heliosphere. The
heliosphere safeguards the planets from interstellar radiation such as cosmic rays. Solar wind
also contains plasma known as solar rays. Second,, is the heliopause, which is the boundary
between our solar system and the ISM. We are fortunate to still have two functioning
spacecraft in the ISM providing direct measurements of it. Most Earth-based observations of
the ISM provide information of farther areas of the region. However, Voyager has provided us
information on the local ISM.
The ISM accounts for over half of mass of our galaxy, regulates star formation, and influences
planetary habitability. When Voyager 1 entered the ISM, solar cosmic rays, which are the
source of energy particles that constantly interact with Earth, were expected to inform
scientists of this transition by way of changes in the direction of magnetic fields. However,
when the magnetic field direction remained the same, scientists were puzzled. What they
found instead were intense changes in magnetic field intensity, and also in plasma density,
which is the number of plasma particles per cubic centimeter. The typical interstellar plasma
density is 100 times larger than inside the heliosphere. So, an increase in plasma density was
indicative of Voyager crossing the heliopause and moving into the interstellar medium. By
contrast, Voyager 2’s transition into the ISM was much smoother, suggesting that the
heliopause boundary is not uniform.
Ocker’s study of the ISM illuminated many interesting details concerning the relationship
between the ISM and our solar system. First, her research revealed that interstellar space is
very turbulent. Solar storms from our Sun move through the heliosphere and send vibrations
through interstellar plasma. For this reason, it is clear that the heliopause is more of a leaky
boundary, than a solid wall, and the solar system and ISM are easily influenced by each other.
Second, Ocker and her team also discovered low level, consistent plasma activity, which they
referred to as the ‘hum’ of interstellar space. Before this discovery, Voyager could only measure
interstellar density during moments of increased activity such as solar storm-related plasma
oscillations. However, the revelation of the hum means researchers can measure interstellar
density continuously. Such research from Earth is virtually impossible because our ionosphere
blocks the low frequency signals – research needs to be done in situ. Unfortunately, we may
have only a few more years of data gathering from the Voyagers as their batteries are failing
and not expected to last beyond 2025. An Interstellar Probe Mission is on the drawing boards
for the 2030’s, based on a 50-year mission, and planned exiting of the solar system much faster
than the Voyagers. Whether such a mission garners the support and funding necessary remains
to be seen.
Finally, scientists know that the sun lives within a grove of interstellar clouds. However, Stella’s
research helped reveal that the sun is heading to and will settle into a different cloud in roughly
2,000 years. As such, conditions within our solar bubble will change once we enter this new
cloud. Only future research will reveal how that affects Earth and the solar system's
relationship with the ISM.
Tour of Globular Clusters:
To close off the meeting, Russ Pinizzotto led us on a tour of globular clusters as part of the
Astronomical League’s summertime observing challenge. The challenge involves 38 possible
targets in the constellations Sagittarius and Ophiuchus. Globular clusters are relatively similar in
shape as most appear to be round. Moreover, most of the clusters in the challenge are brighter
than magnitude 10. To participate in the challenge, observations of at least 12 globulars must
be made from July 1st through September 30th, and reports submitted by October 30 th . See
September’s meeting tour: Vulpecula, Sagitta and Equuleus.
Maame Andoh and Rob Burgess