From The Program Chair

Posted on October 5, 2025 by ST Editors

by Victor Davis, Program Chair

He Who Lives in Harmony with Himself Lives in Harmony with the Universe
Marcus Aurelius

Smooth Moves: Why Strain Wave Mounts are Taking Over
The October, 2025 meeting of the AAAP will take place in Peyton Hall on the campus of Princeton University on Tuesday, October 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.

The evening’s guest speaker, Michael DiMario, chairs this club’s Astroimaging-EAA Group. Due to a misunderstanding regarding meeting dates, Dr. DiMario will step in to take over for Becka Phillipson, who will be rescheduled for a future meeting

Also, Eklavya Doegar and her fellow members of the Unistellar Student Group will show images they acquired with the newly donated “smart” telescope and discuss their experiences using it.

Options for Attending the 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. The meeting will be recorded and edited for posting to our club’s YouTube channel.

No “meet the speaker dinner”
Dr. DiMario has expressed his preference to forego the traditional pre-meeting dinner at Winberie’s.

Here’s the anticipated agenda for October 14, 2025’s monthly meeting of the AAAP:

(Times are approximate)

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.

Featured Speaker:
Michael DiMario
k2mjd@outlook.com

Chair of Astroimaging – EAA Group
Amateur Astronomers Association of Princeton

Smooth Moves: Why Strain Wave Mounts are Taking Over

Smooth Moves: Why Strain Wave Mounts are Taking Over
Telescope mounts have come a long way — from bulky worm gears to sleek, high‑precision systems. Strain wave mounts (also called harmonic drives) are transforming how we track the night sky. By using elastic motion instead of traditional gear teeth, these mounts offer extreme precision, near‑zero backlash, and compact designs. This talk will explain strain wave technology, how it works, compare it to traditional worm‑gear mounts, and explore why it’s becoming a game‑changer for amateur astronomy. No engineering background required — just curiosity and a love of the stars.

Michael DiMario, PhD
Michael DiMario has recently retired from Lockheed Martin serving various executive roles and has held executive engineering positions at General Electric Medical and Lucent Technologies/Bell Laboratories. Michael has six patents, a published book on systems engineering, several published book chapters, more than fifty peer reviewed papers. He has been interviewed and quoted in Wired Magazine, GPS World, Sifted, and the Financial Times. In regard to his astronomical pursuits, he chairs the Amateur Astronomers Association of Princeton Astroimaging Group, spends many a night astroimaging, and does considerable astronomical history research. He co-shares the earliest precovery of Pluto on Edward Barnard 1909 photographic glass plates located at Yerkes Observatory.

How to Participate (Links)
Zoom & YouTube Live
Amateur Astronomers Association of Princeton is inviting you to a scheduled Zoom meeting.
Time: October 14, 2025 07:00 PM Eastern Time (US and Canada)

Join Zoom Meeting
Topic: October 2025 AAAP Meeting-Michael DiMario, PhD, Astroimaging Chair, AAAP
Time: October 14, 2025 07:00 PM Eastern Time (US and Canada)


https://us06web.zoom.us/j/83089664878?pwd=AaaS7f2MG3CwruhRo2vtDitxWFN73A.1 ….https://youtube.com/live/SF9U5-vwuwQ
Click the above icons for Zoom and YouTube

Breakthrough Starshot
When last month’s guest speaker, Edwin Turner, visited Peyton Hall several years ago, his topic was the Breakthrough Starshot Initiative. This now-abandoned project was funded by billionaire Yuri Milner. The idea is to launch tiny probes weighing a gram or so attached to reflective sails into orbit and then use high-powered lasers to accelerate them to 20% of the speed of light and direct them to the nearest stars. The history of this project and its quiet demise are described in a recent article in Scientific American magazine. Apparently both billionaires and politicians can be capricious and arbitrary. You can read the article at https://www.scientificamerican.com/article/the-quiet-demise-of-breakthrough-starshot-a-billionaires-interstellar/

A look ahead at future guest speakers:

Date Featured SpeakerTopic
Nov. 11,
2025		Romain Teyssier
Professor of Astrophysical Sciences and Applied and Computational Mathematics
Princeton University
teyssier@princeton.edu
Prof. Teyssier’s main research activity is to perform simulations of cosmic structure using supercomputers in order to understand the origins of stars and galaxies.
Dec. 9, 2025
Sihao Cheng
Postdoc Member
scheng@ias.edu

Jiaxuan Li
Graduate Student
jiaxuanl@princeton.edu

Eritas Yang
Graduate Student
eritas.yang@princeton.edu		Discovery of Dwarf Planet Candidate in an Extremely Wide Orbit
 
Dr. Cheng and colleagues discovered in publicly available data from the Dark Energy Camera a dwarf planet candidate, 2017 OF201, currently located at a distance of 90.5 au. Its orbit is extremely wide and extends to the inner Oort cloud, with a semi-major axis of 838 au and a perihelion of 44.9 au precisely determined from 19 observations over seven years. Assuming a typical albedo of 0.15, they estimate a diameter about 700 km, making it the second-largest known object in this dynamical population and a likely dwarf planet.
 
Thanks to Nick Mellis for suggesting these speakers.
Jan. 12, 2026Not Yet Scheduled
Feb. 12, 2026
John Bochanski
Associate Professor and Chair,
Department of Computer Science and Physics
Rider University		Dr. Bochanski has been connected to the Legacy Survey of Space and Time Discovery Alliance since his graduate studies more than 15 years ago. Rider University is part of the global effort using the Vera C. Rubin Observatory to map the optical sky. The Rubin observatory (formerly the Large Synoptic Survey Telescope, LSST) will capture more information about our Universe than all other optical telescopes throughout history combined. The observatory released its first images this past June. Prof. Bochanski will discuss the project’s history and discoveries.
 
Thanks to Nick Mellis for suggesting this speaker.
Mar. 10, 2026Robert Vanderbei
Emeritus Professor in the Department of Operations Research and Financial Engineering
Princeton University
 
AAAP Assistant Director
rvdb@princeton.edu
Prof.  Bob Vanderbei will talk about stellar dynamics.
Apr. 14, 2026Not Yet Scheduled
May 12, 2026
John Horgan
Science Writer
horganism3@gmail.com		Mr. Horgan will discuss his controversial 1996 book The End of Science, in which he argues that pure science, defined as “the primordial human quest to understand the universe and our place in it,” may be coming to an end. Horgan claims that science will not achieve insights into nature as profound as evolution by natural selection, the double helix, the Big Bang, relativity theory or quantum mechanics. In the future, he suggests, scientists will refine, extend and apply this pre-existing knowledge but will not achieve any more great “revolutions or revelations.” Shades of Auguste Comte, perhaps?
 
We expect to have copies of his book(s) for sale for the author to sign at the conclusion of his presentation.
 
Thanks to Rex Parker for engaging this speaker.
Jun 9, 2026
Jacob Hamer
Assistant Curator
NJ State Museum Planetarium
Jacob.Hamer@sos.nj.gov		As usual, the June meeting will take place in the planetarium at the NJ State Museum in Trenton. There will be no streaming of this live-only sky show and PowerPoint presentation. Topic to be announced.

As always, members’ comments and suggestions are gratefully accepted and much appreciated. Thanks to Ira Polans and Dave Skitt for setting up the online links and connecting the meeting to the world outside Peyton Hall.

victor.davis@verizon.net
program@princetonastronomers.org
(908) 581-1780 cell

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Minutes of the September 9, 2025 Meeting

Posted on October 5, 2025 by ST Editors

by Gene Allen, Secretary

Director Rex Parker opened the meeting in Peyton Hall at 1930 with 54 attending. He reported:

The new website, under construction by Member Jeff Pinyan for many months, is available as a beta version to try out at https://www.princetonastronomy.org/beta. When fully implemented, a login will offer members to exclusive content and functionality.

Member David Ackerman is also a member of Dark Sky International and DarkSky New Jersey. Earlier this year he founded DarkSky Hopewell to remediate bad lighting in Hopewell Borough. His team has helped the Hopewell Village Square convert to dark sky compliant lighting and has two more businesses waiting to follow.

Astroimaging Chair Michael DiMario, PhD will be giving a talk Before Pluto Was Pluto at the Morris County Library in Whippany, NJ on Saturday, September 13.

Restoration of power to the observatory continues to await the glacial response of JCP&L.

NJAA will hold their annual open house and astro flea market on September 13 in High Bridge, NJ.

Program Chair Victor Davis introduced our speaker for tonight, Dr. Edwin L. Turner, Emeritus Professor of Astrophysical Sciences at Princeton University. His talk, An Observable Universe Devoid of Extraterrestrial Life, Intelligence, and Technological Civilizations Is Plausible, was delivered in person. He showed how many of the presumptions about the likelihood of extraterrestrial life are emotional and not determinant.

Thirty minutes of questions and a break followed the talk.

Rex convened the business meeting at 2122 with 16 attending in Peyton Hall. Fifty years ago Viking 1 was the first spacecraft to successfully land on another planet (Mars) to begin a search for biology. Member Rich Sherman shared images he made of the Antenna Galaxies and Rex showed his of the Trifid and Iris Nebulae, demonstrating that it is nebula season. The NSF-DOE Vera C. Rubin Observatory on Cerro Pachon in Chile had first light on the world’s largest camera on June 23. Later this year Rubin will begin its Legacy Survey of Space and Time, scanning the sky for 10 years to precisely capture every visible change.

< https://rubinobservatory.org/news/first-imagery-rubin >

Outreach Chair Bill Murray reported on three upcoming outreach events:

Friday, September 12: only 4 have volunteered to take scopes for 100 observers at the Plainsboro Preserve. We need more please.

Week of September 22-26: Active Day Of Hamilton is seeking astronomers to give talks to their adult day care participants. Only Assistant Director Bob Vanderbie has volunteered so far. < https://www.activeday.com/locations/active-day-of-hamilton/ >

Thursday, November 13: Stone Bridge Middle School in Allentown NJ has invited AAAP to provide educational materials and stargazing, weather permitting, at their science fair. We manned a table there last year.

Observatory Co-Chair Dave Skitt reported that Washington Crossing State Park is getting a new visitor center but neither the parked JCP&L trucks nor the extra funding has enabled any improvements in the gates or roadway to our observatory.

A member reported great skies when attending the Maine Astronomy Retreat at the Medomak Retreat Center, August 18-24. < https://astronomyretreat.com/ >

A comment was made that we really need to get funding for a Mars Sample Return mission to bring back the numerous samples already collected and packaged by the Perseverance rover.

The meeting was adjourned at 2200.

As of September 8, we have 215 active members. So far in CY2025, renewals number 86 and expirations number 42, giving us a 67% retention rate. We have added 36 new members.

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Minutes of the September 15, 2025 AAAP Board Meeting

Posted on October 5, 2025 by ST Editors

by Gene Allen, Secretary

Minutes taken from the Zoom recording of the meeting.

The meeting convened at 1900 on September 15, 2025

In attendance:

Director Rex Parker
Treasurer Ira Polans
Program Chair Victor Davis
Secretary Gene Allen (joined late)
Observatory Co-Chairs Jenn & Dave Skitt
Outreach Chair Bill Murray
Astroimaging Chair Michael DiMario
Editor Surabhi Agarwal

Rex, Dave, and Michael briefly reviewed the two quotes for replacing the failed underground power line between the pole and the observatory panel. The quotes were sent to everyone in advance and have been made part of this document. Discussion followed which fairly quickly revealed a preference for the Holcombe Electric estimate. It seems perfectly adequate and complete, supports a smaller, more local business, and comes in at $4,000 less. They had done good work for Michael in the past, and we may be able to get on their schedule more promptly. The motion to have Holcombe do the job was seconded and approved unanimously.

To recap, a UniStellar eVscope 2 was donated to the club last spring. After polling all members for a project team to take on learning the scope and presenting to the membership, some 16 youth members responded enthusiastically. The scope was handed over to them with the expectation that they will organize themselves to learn to use it and then make an Unjournal Presentation, now scheduled for the October meeting.

Rex has been coordinating with them, and Jason Mak, a high school age Keyholder, is requesting that we officially establish a youth subgroup. Pros are that it will add legitimacy to youth membership, we can Bill expects they can be a great outreach resource at events such as the Stone Bridge Middle School Science Fair coming up again in November. Dave has seen youth interest at a recent event at Plainsboro Preserve. The group should remain mostly self-organizing with little structure forced on them. They should be members, but Dave, Mike, and Surabhi spoke out for implementing tiered memberships. The only con that came up is that they will age out of the group and it may not be self-sustaining. Connecting with astronomy club advisors that we think exist in most schools should help keep youth membership refreshed. There does need to be a formally appointed advisor, and our Assistant Director Bob Vanderbie has the panache of being a retired Princeton University Professor. [In completing these minutes, it was noted that he had accepted that role at our April Board Meeting.] Dave kept coming up with projects we could suggest to them, including a human sundial, a solar system walk, creating a real-world horizon from panographic photos for The Sky X software that runs our observatory scopes, and manning the greeting and literature table function at the observatory. There was universal support for creating a youth member subgroup.

The failed underground power cable to the observatory has been replaced, but the trench refill was done poorly, with many sharp-edged rocks making it a hazard. A motion, second, and unanimous approval vote authorized spending $2000 to pay a landscaper recommended by Michael Mitrano to clean it up. Dave will follow up. JCP&L continues to be even more unresponsive in hooking us up than the state. It was noted that the end of the conduit at the building is open and that the electrician responded that a weather head was not included in the quote, though it probably should have been.

Michael DiMario reported that the astroimaging Group.io free account is using 80% of its free allotment of 1GB for archiving both images and the conversations supporting them. He expects it to be full early next year and proposes that the lowest paid increment provides 30GB and costs about $200 a year. While only 10 or so out of the 45 or so in the group provide most of the images and discussions, he finds 20% active participation is also shown in the other two astronomy clubs to which he belongs. At present, EAA does not comprise much of the activity, and the introductory description should add that. A motion, second, and unanimous approval vote authorized spending the annual $200.

The beta website has generated no feedback and it is suggested that having two sites in parallel is confusing and not as productive as we had hoped. There was consensus that we need to migrate content from the old website to the new, populating the blank blue boxes and preparing to go officially live with the new site around about the first of next year. The website team will see what Jeff’s plans are. In that process, Mike suggested that we make the Sidereal Times newsletter a members-only benefit, as it is at his other clubs. Since everything else we do is free to the public, that would make it a reason to pay dues and might add legitimacy to the document. It could be moved to beyond the members login with little trouble, and Surabhi reported that a “teaser” extract on the public side could easily be created to entice joining.

Bill noted in closing that the planetarium is planning to bring groups to the observatory on October 10 and 24.

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Cozy Layers

Posted on October 5, 2025 by ST Editors

by Rich Sherman, Merchandise Chair

Greetings from the AAAP Store! AAAP store!

We will shift our inventory from warm weather to cool weather gear on October 15.  Don’t forget AAAP gear makes a great holiday present! If you want a different color just email me at merchandise@princetonastronomy.org, and I will do my best to get you what you want.    

We also offer a wide range of non-apparel items at our Next Gen Store—from bags and magnets, to towels and cups, and lots of stuff in between. The password for both is:  SiderealTimes.

You can also reach our stores by clicking here: AAAP Shopping

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From Princeton to Pleiades: Adventures with a Smart Telescope

Posted on October 5, 2025 by ST Editors

by Robert Vanderbei, Assistant Director

I’ve been having lots of fun with my Seestar S30 smart telescope. Over the last week or so I took pictures of the Andromeda galaxy, the Orion Nebula, and the Pleiades. As I’m sure many/most of you know, I have for about 8 years been teaching a Freshman Seminar here at Princeton University called “Sizing Up The Universe”. The course is all about how we can measure distances to things using data/pictures acquired using cameras and telescopes that are affordable to amateur astronomers. We start by measuring the size of Earth, then the size of and distance to the Moon, followed by the Sun and other planets in our solar system. After that we use pictures I’ve taken over multiple years of Barnard’s star to measure its parallax and hence its distance. Then toward the end of the semester, we study RR-Lyrae stars and use them to measure the distance to some globular clusters near our Milky Way galaxy and from those distances we estimate roughly how big our Milky Way galaxy is. Then, we notice that there are some globular clusters that can be imaged in nearby galaxies and comparing the angular size of those far away globulars to the angular size of our nearby globulars we are able to estimate the distance to some of our nearby galaxies. Lastly, we study some pictures I’ve taken of Quasar 3C-273 using a diffraction grating that I bought. From those pictures we are able to measure the red-shift of that quasar. These things are all very fun to do and in previous years I’ve mostly used pictures taken with my 10″ Ritchey-Chretien telescope together with cameras I’ve bought from StarlightXpress.

This year, we are doing things a little differently. The Freshman Seminar program has bought eight ZWO Seestar-S30 smart telescopes so that the students in the class (there are 15 of them) can take their own pictures of things. My hope is that maybe we’ll use some of those pictures for our analysis. With those goals in mind, I have started taking pics with my own Seestar-S30. I’m having lots of fun. It’s both easy to do and the images captured are amazingly good for such a small telescope. Shown here are three of the pictures I took recently.

The first picture is of the Andromeda galaxy (aka M31). It was taken in the evening on September 19. The image is a stack of 480 10-second exposures, i.e., 80 minutes. I used the Seestar app in “Mosaic” mode. As I recall, I enlarged the image to be about 70% larger than the base size of the camera. When doing mosaic mode, there is a significant temporal gap between exposures because the app moves from one position to another position after every exposure. So, the 80 minute total exposure time took about twice that long to get.

The second picture was taken of the Orion nebula (aka M42) in the early morning hours of September 22. The image is a stack of 210 10-second exposures, i.e., 35 minutes. This picture was also taken in “Mosaic” mode but the size was not upscaled. I only used mosaic mode so that I could orient the picture so that we can see Orion’s sword in a vertical orientation. The nebulosity we see around those few bright stars near the top is called the Running Man nebula, aka NGC 1977. Those stars are the “top” of Orion’s sword. And, of course, Orion’s nebula is the large interesting nebula at the center of Orion’s sword. And, lastly the few bright stars similarly far down below the Orion nebula form the bottom of Orion’s sword. Visually, the top, middle, and bottom of Orion’s sword just looks like three stars but here we see that it’s actually more than three stars.

M42

The third picture is of the Pleiades (aka M45). It was taken in the earlier morning hours of September 22. It’s a stack of 105 10-second exposures, i.e., 17 minutes. And, it too was taken in “Mosaic” mode so that I could orient the picture with north at the top, east at the left, etc.

M45

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The Bubble Nebula

Posted on October 5, 2025 by ST Editors

by Michael DiMario, Astrophotography Chair

The Bubble Nebula NGC 7635 is located in the constellation Cassiopeia 7100 light year from Earth. It is 7 light years across and is a glowing molecular cloud due to a very hot central star. The bubble molecular cloud is expanding at 4 million miles per hour. This image was captured with a Celestron C9.25 telescope with a 0.7x reducer, ZWO ASI2600MC Pro camera, and Optolong L-Ultimate filter. PixInsight was used for post processing 250 light frames of 300 sec each for an integration of 20.8 hours over a course of 4 nights.

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The Pulsar Map

Posted on October 5, 2025 by ST Editors

by S. Prasad Ganti

A recent news item piqued my interest. The National Air and Space Museum in Washington DC opened 5 new galleries. In the “Boeing milestones of flight hall”, etched on the floor is a set of radial lines emanating from a central point. This is the Pulsar map. It is a map showing the bearings of our planet earth with respect to 14 known pulsars, some in our galaxy and some outside. Pulsars are spinning remnants of once massive stars. These emit pointed beams of radio waves which is what the radial lines in the map represent. 

Stars end their lives and become smoldering remains of once glowing nuclear furnaces. Smaller stars like our Sun become white dwarfs after death. While massive stars become neutron stars and black holes. Neutron stars are very dense objects where the electrons and protons of all the matter collapse into neutrons. Some neutron stars spin very rapidly and emit radio waves in focused beams from their poles. These neutron stars are known as pulsars. Something like light beams coming from a light house. Not all neutron stars have their beams coming towards earth. Some of them do. And 14 of them were selected to guide any alien to make the trip to the earth ! The picture below, courtesy National Air and Space Museum, shows the pulsar map on the floor. All the radial lines are not equal in length. The length indicates the distance of earth from the given pulsar. 

The Boeing Milestones of Flight Hall Gallery 100 at the National Air and Space Museum in Washington, DC. July 2, 2025. (Smithsonian Photo by Mark Avino) [20250702.MA.117] [NASM2025-03405]

The Pulsar map is very similar to the earlier navigation used by airplanes in our skies. There are a number of special radio sources installed on the ground, which transmit 360 different radio signals to indicate the 360 degrees of the direction from the source. Airplanes have specialized radio receivers which can receive these signals and specify which radial the plane is currently on. Similarly, another radial from another source can specify radial with respect to the second source. The intersection of the two radials provides the location of the airplane. Now, this is supplanted to a large extent by GPS navigation which works everywhere on the earth, even where there are no radio transmitters.     

How do we know how far the pulsars are ? The spinning pulsars send radio waves. The pulse period, related to the frequency of the emitted radio waves, indicates the distance from the earth. 

NASA launched 2 spacecraft Voyager 1 and Voyager 2 in the 1970s to make a grand tour of the outer gaseous planets – Jupiter, Saturn, Uranus, Neptune. And then they made their way across the outer solar system to interstellar space. A memento called “Voyager golden record” created by a committee led by famous astronomer Carl Sagan was put on these 2 spacecraft. A gold-plated phonograph record which contains images, greetings in 55 languages, diverse music, sounds of earth, and the Pulsar map. The Pulsar map itself was designed by Carl Sagan and another famous astronomer Frank Drake. These spacecraft also carry the needle used to play the golden record ! Any such modern day spacecraft would carry USB memory sticks instead ! The picture below, courtesy NASA, shows the details of the golden record. 

The Pulsar map is not a static image which can ensure accuracy for centuries. Things keep changing all the time. Pulsars move. Our solar system moves around the center of our galaxy. An older version of the Pulsar map was sent on Pioneer 10 and Pioneer 11 spacecraft, which predated the Voyagers. What we have in the museum is the latest version, even later than what went on Voyager. 

The museum is getting a lot of face lift. Some more galleries are coming up next year. It will be time to make the pilgrimage again !

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