From the Director

Posted on November 5, 2017 by ST Editors

Rex

 

 

 

by Rex Parker, Director

Dark Skies, Our Eyes, and Outdoor Lighting.
Nearly three-fourths of all Americans reside under skies where the Milky Way is not visible. It’s natural as we age to lose some night sky acuity, as our upcoming guest lecturer, author James Chen, will discuss on November 14 (see the section by Program Chair Ira Polans in this issue). But in addition to aging eyes, worsening light pollution translates to further loss of night vision especially in NJ and the northeast. Among several aspects to this issue, one that I want to bring to your attention is skyglow, the increased sky brightness arising from light scattered by aerosols and molecules in the atmosphere.

Initial optimism for replacing outdoor lighting fixtures with energy efficient solid state LED luminaires, originally thought to reduce light pollution, has recently turned to concern within the astronomy community. As installation of the new LED technology expands around the country, it has become apparent that the relatively blue-rich LED spectrum actually worsens visual skyglow. This unfortunately diminishes the ability of the dark-adapted eye to see stars and the Milky Way, and worsens the contrast of faint deep sky objects in telescopes. Compared to the yellow-shifted emission spectra of the historically most used lighting fixtures, high or low pressure sodium vapor, the adverse effects of blue-rich LEDs are an ominous new threat to our remaining natural night skies.

This emerging well-intentioned effort to replace older outdoor lighting fixtures with newer LED lighting is going to make our astronomical lives more difficult because of the shift in light source spectrum. Most of the discussion about these light sources concerns their favorable electricity usage and profile for normal light adapted (photopic) vision, which is physiologically distinct from night (scotopic) vision. Scotopic vision is dependent on the eye retina’s rod cells which are sensitive to shorter wavelengths of light (blue to green) and insensitive to longer wavelengths (red). This is why light sources richer in short wavelengths stimulate our dark adapted vision and make artificial sky luminance we perceive as skyglow. A recent report by US Naval Observatory astronomer Christian Luginbuhl describes this situation in depth (Journal of Quantitative Spectroscopy & Radiative Transfer 2014, 139: 21–26.) Another good discussion of the topic including several spectrum examples of the various lighting types can found here: http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-light-pollution/.

One solution to the problem is to promote a change to yellow/amber-filtered LED sources, which are becoming available from manufacturers. I urge AAAP members to become more informed by reading up on these complex issues and spreading the message to use amber filtered LEDs whenever possible, while there is still a chance to make widespread changes.

Skynet Update. Taking other steps to mitigate skyglow and loss of night vision, to date 26 members have requested Skynet accounts, and 9 of us have taken images with the Skynet robotic telescope network. Our arrangement with the University of North Carolina, Chapel Hill, Physics and Astronomy Dept, provides remote astrophotography access using state of the art telescopes, mounts, and CCD cameras and software. The instruments are located at observatories spanning the globe. This is an exclusive benefit of AAAP membership, as we seek to gauge interest among members for deeper learning about astro-imaging technologies and approaches. If you’re interested but haven’t yet taken the plunge, send me an e-mail note and I’ll provide you with an account to log-in to the system.

Mark Your Calendar for Next Year’s StarQuest. At last month’s meeting we voted to continue the Jersey StarQuest tradition next year. We’ve reserved Oct 5-6, 2018 at Hope Center in north Jersey where the effects of light pollution are less than around Princeton. The deep sky observing conditions at Starquest-2017 last month were among the best we’ve had in New Jersey, reminding us why we pursue such a challenging avocation as seeing faint, distant galaxies and nebulae with our own equipment through our own eyes!

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From the Program Chair

Posted on November 5, 2017 by ST Editors

By Ira Polans

James Chen

The November AAAP meeting will be held on the 14th at 7:30PM in Peyton Hall on the Princeton University campus. The talk is by James Chen on his book “Astronomy for Older Eyes”. This month we are introducing a new format to the meetings. After the Rex’ introductory comments one of our members will give a 10 minute talk on an astronomy related topic. This will be followed by the guest speaker’s presentation. Then there will be the regular break followed by the business meeting.

Jim Chen’s book is for the aging amateur astronomy population, including newcomers to astronomy in their retirement and hobbyists who loved peering through a telescope as a child. Whether a novice or an experienced observer, the practice of astronomy differs over the years. This guide will extend the enjoyment of astronomy well into the Golden Years by addressing topics such as eye and overall health issues, recommendations on telescope equipment, and astronomy-related social activities especially suited for seniors.

Many Baby-Boomers reaching retirement age are seeking new activities, and amateur astronomy is a perfect fit as a leisure time activity. Established backyard astronomers who began their love of astronomy in their youth, meanwhile, may face many physical and mental challenges in continuing their lifelong hobby as they age beyond their 55th birthdays. That perfect telescope purchased when they were thirty years old now suddenly at sixty years old feels like an immovable object in the living room. The 20/20 eyesight has given way to reading glasses or bifocals. Treasured eyepieces feel all wrong.

Growing old is a natural process of life, but astronomy is timeless. With a little knowledge and some lifestyle adjustments, older astronomers can still enjoy backyard observing well into their seventies, eighties and even into their nineties.

During the break James’ book will be available as part of a book signing.

Our first 10 minute talk will be given by Peter Wraight. Peter will talk about two topics “A Different Approach to Building Astronomical Binoculars” and “A Generalized Coordinate and Finder System for Locating Celestial Objects” For the first topic Peter will present binocular designs that attempt to overcome some of the drawbacks of regular binoculars for astronomy. Two examples will be shown: one using 100 mm f/4 objective lenses and the other using 6 inch f/5 mirrors. The second topic is about the Tri-Finder system a fully generalized star reference coordinate system which enables a telescope to be pointed to within 0.5 degrees of any absolute position in the sky by only using two guide stars of 3rd magnitude or brighter. This accuracy is available over the entire sky and is achieved without any specific alignment or precision of the telescope mount.

If you are interested in giving a 10 minute talk at a future meeting please contact me at program@princetonastronomy.org. Please let me know the topic and your availability.

Prior to the meeting there will be a meet-the-speaker dinner at 6PM at Winberie’s in Palmer Square in Princeton. If you’re interested in attending please contact program@princetonastronomy.org no later than Noon on September 12.

If you have suggestions for speakers please send them to program@princetonastronomy.org. Please provide the speaker’s name, topic, and affiliation. Thanks!

We look forward to seeing you at the September meeting and the dinner!

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October 10, 2017 Meeting Minutes

Posted on November 5, 2017 by ST Editors

by Jim Poinsett, Secretary

Minutes of the October 2017 Meeting of the AAAP

• Rex called the meeting to order at 7:30

• Two speakers for the evening

    –  Arshad Jiliani showed the video he compiled of the trip to Oregon to view the total eclipse taken by a group of club members. He also answered some questions during a brief Q&A session afterwards.

   –  Rex Parker explained how to sign up and use the club membership to take photos using the Skynet Robotic Telescope Network. It is a free benefit for all club members interested in using it.

• After the break, the first topic discussed was the club sponsored star party, Star Quest. This year was possibly the best weather ever for the event, everyone who was able to attend had a great time. Next years event will be held on the weekend of October 5-6, 2018. A change in pricing will be discussed at the board meeting as the fee charged only covered about 50% of the expense.

• The observatory was the next item discussed. This has been a very good year for the observatory with few weeks to go. The equipment has held up very well.

   –  The Mewlon’s image is less than ideal. It needs to be collimated. Takahashi sells a tool to do this, it is about $400 but would also be adaptable for use on member owned scopes. The board will discuss buying it at the next board meeting.

   –  A discussion was held on the need for better monitor for the video camera. The possibility of needing a higher resolution camera was also brought up as an alternative. Further discussion will be held before the next viewing season.

   –  The topic of security at the observatory was also brought up. With the additional equipment better security is warranted and with the addition of internet access better security is readily available. Several options will be prepared for the board meeting in December.

• The program committee is looking for members to give about a 10 minute presentation at our meetings. Anyone interested in showing or discussing a topic that interests them please let the program chair know.

• There being no more business do discuss, the meeting was adjourned.

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Videos of Total Solar Eclipse taken by AAAP members.

Posted on November 5, 2017 by ST Editors

Total Eclipse Story 2017 – by Arshad Jilani

The sky and horizon at totality – submitted by Joy Saxena, shot by Pallavi Narain

Time lapse video of the sky before, during and after totality – submitted by Joy Saxena, shot by Pallavi Narain

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Gravity Waves and the Higgs Boson

Posted on November 5, 2017 by ST Editors

by Prasad Ganti

Aerial view of LIGO. Credit - Dailymail

Aerial view of LIGO. Credit – Dailymail

Gravity waves have been in the news for the last two years or so. Firstly, when the hundred year old prediction of Albert Einstein came true. Gravity waves were discovered when two black holes collapsed into one, about a billion light years away. The feeble vibrations of space-time was heard by two well engineered and sensitive detectors called LIGO (Laser Interferometer Gravitational-Wave Observatory). Few more such observations have been made over the last two years. The most recent one resulting from a neutron star collapsing into a neutron star.

When a massive star, tens of times heavier than our Sun dies, it ends up as a neutron star and possibly a black hole. Being so dense and compact, both of them represent gravitational extremities. Neutron stars can be detected by radio and optical telescopes but black holes can only be detected indirectly.

Weiss, Thorne, Barish

Weiss, Thorne, Barish

Upon finding the evidence for a century old prediction by the all time great physicist Einstein, the Nobel prize for Physics in 2017 was awarded to Kip Thorne, Rainer Weiss and Barry Barish for their work on gravity waves. These waves were undetected for a century mainly because they are very very weak. They result from very violent cosmic events like merger of gravitationally intense objects like black holes and neutron stars. These events do not happen frequently in our galaxy. Certainly not in our neighborhood. If they did, we would not exist anymore. Happening at far away distances, the waves travel at the speed of light, and get attenuated on the way to almost the level of insignificance.

Lot of sensitivity in the instrumentation is required to detect such feeble signals. And the noise resulting from other sources needs to be subtracted. Rainer Weiss had analysed the possible sources of background noise that would disturb their measurements. He had also designed a detector, a laser-based interferometer, which would overcome this noise. Basically consisting of two arms in “L” shape running across several miles, with very precise mirrors in both the arms. And a laser beam bouncing back and forth. If there is any disturbance in space-time, the two beams would be out of sync, almost by a whisker. It was necessary to develop new laser technology and invent new materials, as well as construct gigantic vacuum tubes, seismic isolation and other vital technology far beyond what had previously been achieved. Two such detectors were constructed (One in Louisiana and another in Washington state) to eliminate any false alarms resulting from local incidents. Now a third detector in Italy joined the fray.

LIGO. Credit - The Optical Society of America Inc.

LIGO. Credit – The Optical Society of America Inc.

In 1994, when Barry Barish took over as leader for LIGO, he transformed the small research group of about 40 people into a large-scale international collaboration with more than a thousand participants. He searched for the necessary expertise and brought in numerous research groups from many countries. Thus, big science and sophisticated engineering came together. Reminds me very much of the LHC (Large Hadron Collider) in Geneva, Switzerland, which led to the discovery of Higgs Boson, another monumental discovery of this decade. This led to a Nobel prize in Physics to Peter Higgs and Francois Englert in 2013.

Kip Thorne was instrumental in setting up of LIGO. In addition, he was a consultant and an executive producer of the science fiction movie “Interstellar”. The special effects in the movie were pretty close to realty. The graphics team which created the special effects worked very closely with Thorne who worked out several equations to bring a sense of credibility to the imagination. I am glad that Throne won the Nobel prize. Though the prize is not for the movie.

The most recent detection of gravity waves resulted from the collision of two neutron stars. The difference this time being that as soon as the waves were detected, other telescopes and observatories were notified. There was detection of other signals from the same event. Gamma rays were detected by the Fermi observatory in space. Several telescopes detected optical and radio signals as well. It was the first time when multiple scientific devices were able to track a mega cosmic event and study its aftermath.

It is a watershed event in the history of science when such mega projects come together to witness a significant cosmic event, amplifying the human ability to study the cosmos in such detail and depth.

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Fortuna ipsa muta

Posted on November 5, 2017 by ST Editors

by Ted Frimet

sheer dumb luck

Not everything is as it seems. And sometimes, despite months or years of amateur training, a gain in insight can be chalked up to “sheer dumb luck”. As most of our AAAP club members are aware, I’ve been hunting an asteroid. And J2012 TC4 came into our field of view, quite nicely in fact, on October 11, 2017 – between the wee GMT hours of 04:01:28.432 and 04:04:38.185. Ten images, at 5 second exposure each, were captured with the Prompt-8 telescope, located at Cerro Tololo Inter-American Observatory, Chile.

APERTURE: 0.6 m
FOCAL LENGTH: 4000.0 mm
F-RATIO: 6.6
FILTERS: B, V, R, I, Red, Green, Blue, Lum, Clear
CCD SIZE: 2048 x 2048 (13 um pixels)
FOV: 23.8 x 23.8 arcmins
SITE: Cerro Tololo Inter-American Observatory

Snippet from skynet robotic telescope network prompt 8 status page, Saturday, October 28, 2017.

The telescope location is at latitude -30:10:3.300’, longitude -70:48:19.200’ (negative means“South”). Why, oh why is he giving us coordinates for his telescope? As I learned, a month before making a Near Earth Object (NEO) observation, the number one thing to remember in Outer Space Real Estate is, “LOCATION, LOCATION, LOCATION’ ! ! !

Sounds easy. Yet, here I am weaving a Saturday morning tale of “woe is to me”, for testing the limits of unknown parameters. I unknowingly ran smack dab into ye old Murphy’s Law. I didn’t know that Murph held title to an NEO. Despite being fenced in by my own mistakes, Murph told me that good fences make good neighbors, and he let me take a peek at the old gal for 10 decent exposures.

What went wrong? Nothing really. That is if you do not count the fact that Skynet – and I must stress – PROPERLY – dispatched my observation requests to sites other than Chile. We took a swing by the R-COP telescope, located at Perth Observatory, Australia, as well as a side-step to the Dark Sky Observatory, DSO-17, in North Carolina, USA. Neither of these observations were validated with an asteroid find. And that, my fellow amateurs, is because the detail lay in the ephemeris data.

I was feeling fresh and all squeaky clean from a visit to NASA’s JPL Horizon database for ephemeris data on our asteroid. I wistfully entered data into the Skynet Robotic Telescope Network Advanced mode. At the time of generating the ephemeris data, I changed my locus to the La Serena site, in Chile, where the Prompt telescopes are given astronomical sanctuary. I made specific requests to match the Right Ascension (RA) and Declination (DEC), gleaned from said ephemeris, right into Skynet, with a matching specified “time of capture equals past mid-night”. I was galavanting past midnight (as my Grandmother would say).

And there’s the rub. Skynet is programmed to direct your request to the next available telescope in your observers list. As I didn’t want to get cheesed out of targeting my asteroid, I left in a healthy dose of alternative ‘scopes. Sans the matching ephemeris data. And that’s when ‘ol Murphy stepped in. If you were imaging stars, your location wouldn’t be quite as critical. However, when you are locating a NEO that is one-tenth Lunar distance from the Earth, your location is important. Ouch. Parallax became the answer to a month long question, as I reviewed, and generated movies for the Australian data, some 6 or 7 times, – leading to negative results.

As I may have mentioned to one or few AAAP members, I do not fear the consequences of failure. I endure, and learn from every miss-step I encounter. I am sure that if I had allowed SkyNet to select my RA/DEC, and automatically reassign to telescopes in waiting, all would have been well. However, my ego got in the way, and I felt that exercising an additional degree of control would be for the better. Nope. I built that fence for Murph, all by myself. “Scored an own”, as the British say. As I found out, a month later, my newest neighbor even tossed in a free doorpost, as the DSO in NC, was of course, not located in a La Serena, observers location.

At the time of this writing, I was planning on establishing tighter magnitude measures of 2012 TC4. I was going to make lemonade out of the lemons of R-COP and DSO-17. The elephant in the room, is of course, parallax and that there is no data to measure in those astro-images.

I am planning to program a course of observations of Algol, a variable star, from minimum to maximum, to map out its magnitude (thanks to John Church, AAAP for pointing out the RASC data on the web). And to compare the results to knowns, so as to establish my own candlestick. And then to revisit the 10 successful images taken by Prompt-8 and re-sample the magnitudes, and make some coarse adjustments. Armed with some self-obtained results, I will be able to compare my magnitudes with the NASA data, and decide if the asteroid is closer to being 15 meters or 28 meters wide. Or perhaps, if it emits more light than predicted (thanks to Gregg Waldron, NWJAA for pointing this out) – that I have proof that 2012 TC4 is a younger asteroid, as opposed to being an old beaten space rock, not unlike my neighbor, ‘ol Murph.

Please note that although hundreds of observations were made of this NEO, there were only two observatories that posted videos that focused primarily on the science of the asteroid. That was the Kiso observatory in Japan (whose primary focus is on super-novas), and our video composited from the images taken from Cerro Tololo – whose credit of telescope stewardship can be found with Dr. Dan Reichart of UNC, Chapel Hill, as they hunt for the after glow of gamma ray bursts.

Video, as promised:

Posted in November 2017, Sidereal Times | Tagged , | Leave a comment

Snippets

Posted on November 5, 2017 by ST Editors

compiled by Arlene & David Kaplan

Colliding neutron stars - NPR

Colliding neutron stars – NPR

Astronomers Strike Gravitational Gold In Colliding Neutron Stars
For the first time, scientists have caught two neutron stars in the act of colliding, revealing that these strange smashups are the source of heavy elements such as gold and platinum…more

-BBC

-BBC

The place spacecraft go to die
China’s Tiangong-1 space station is currently out of control and expected to fall back to Earth next year. But not in the remote place where many other spacecraft end their days. Explorers and adventurers often look for new places to conquer…more

-NASA/JPL

-NASA/JPL

Nasa carbon space observatory ‘watches Earth breathe’
A Nasa satellite has provided remarkable new insights on how CO2 is moved through the Earth’s atmosphere. The Orbiting Carbon Observatory (OCO) tracked the behaviour of the gas in 2015/2016 – a period when the planet experienced a major El Niño event…more

-NASA/JPL


Astronomers Race to Study a Mystery Object From Outside Our Solar System
For the first time that we know, an interstellar visitor has zoomed through our solar system. The small space rock, tentatively called A/2017 U1, is about a quarter of a mile long and astronomers across the world are racing to study it before it departs just as quickly as it arrived…more

Sync your calendar with the solar system
Add the calendar on Google or iOS…more

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From the Director

Posted on October 3, 2017 by ST Editors

Rex

 

 

 

by Rex Parker, Director

A Perfect StarQuest Weekend in Hope NJ. The 23 AAAP members who convened at the Hope Conference and Renewal Center in northern NJ Sept 22-23 had a truly stellar weekend with warm weather and the clearest skies we’ve had in a long while. The Milky Way was readily visible high overhead and many of the Messier and NGC objects we sometimes struggle to see were being picked up by nearly everyone on the observatory field. Several moderately sized portable refractors (3-5 diameter lenses) set up on equatorial and alt-az mounts turned heads all night long with remarkable displays of real-time CCD imaging. This technique, referred to as electronic-assisted astronomy (EAA) continues to develop as an area of high interest in our club. A variety of portable Schmidt-Cassegrains and Newtonian telescopes were also on display, including the novel binocular telescopes with original triangulation-finding method designed and made by member Peter Wraight.

At the October meeting we’ll ask the question – shall we continue the StarQuest tradition and request a reservation at Hope Center again for fall 2018? The low moon weekends to consider are Sept 7-8, Oct 5-6, and Nov 2-3 in 2018 – please give it some thought.

Telescopes are readied as darkness descends on the observing field at Jersey StarQuest Sept 23 in Hope NJ.

Goodbye Cassini – Now Part of Saturn. Always remember the amazing and beautiful images and the science discoveries made by Cassini and it’s project team in the nearly-20 year mission to Saturn. A good way for us to keep those memories alive is to see Saturn with our own eyes. Now the giant ringed planet is well-positioned for splendid telescopic views just after sunset this month. Members of AAAP as well as the public can see Saturn – and imagine the ghost of Cassini – through our state of-the-art telescopes at Washington Crossing Observatory each Friday night through the end of October. Members also have the privilege to be at the observatory any other night if a trained keyholder has opened and is using the facility, preferably before colder weather arrives. To participate send your request, indicating which nights you’re interested in coming to the observatory, by e-mail to keyholders@princetonastronomy.org.

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From the Program Chair

Posted on October 3, 2017 by ST Editors

By Ira Polans

The October AAAP meeting is on the 10th at 7:30PM in Peyton Hall on the Princeton University campus. The presentation will be divided into two 30 minute parts. The first part is “The AAAP’s 2017 Total Solar Eclipse Trip to Monmouth, OR” by club member Arshad Jilani. The second part is “Astro-Imaging with Skynet” by AAAP Director, Rex Parker. The October presentations wrap-up our talks about the solar eclipse and promote a new member benefit.. The October presentations wrap our talks about the solar eclipse and promote a new member benefit.

Arshad Jilani at Mauna Kea
Rex Parker with his telescopes.

The Great American Eclipse of August 21, 2017, is an event that amateur astronomers and others across the US will remember for a lifetime. Arshad Jilani and other AAAP team members went to Monmouth, OR, near Portland, to observe the eclipse. Since Monmouth was in the path of totality, they were able to see the eclipse as could only be observed from such locations. Arshad recorded the event and gives us an interesting personalized insight into the people, the drama, the location and of course the event itself as it unfolded for the rapturous observers. He has used a number of member photos and videos to bring the occasion to life for the rest of us

Telescopes and imaging technologies and software are essential tools of the trade to professional and amateur astronomers alike. However, for most of us breaking in to astro-imaging has high entry barriers. To provide a practical path to learning, AAAP has obtained access to Skynet, a remote astro-imaging network developed by the Univ. of North Carolina, Chapel Hill, Physics and Astronomy Dept. The Skynet telescopes typically are 16” imaging scopes with large format CCD cameras located all over the world. In this talk, approaches to remote imaging will be discussed with emphasis on Skynet. Members can begin learning hands-on remote astronomical imaging at no cost through access to Skynet provided by AAAP.

There will not be a club dinner prior to the meeting.

Looking forward to you joining us at the October meeting!

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From the Treasurer

Posted on October 3, 2017 by ST Editors

By Michael Mitrano

The income statements and balance sheet show the AAAP’s financial results for the fiscal year that ended on June 30, 2017, and the AAAP’s financial position at the beginning and the end of the year.

You will see that the AAAP had a deficit for the fiscal year that roughly equals the amount spent on observatory upgrades. During the year, we added the Mewlon telescope with several eyepieces and replaced the computer equipment. Under the AAAP’s method of accounting, investments in equipment that has long-term benefit is shown as an expense in the year we purchase the equipment.

StarQuest also showed a significant loss. 2016 StarQuest’s revenue was lower than in past years, when the events ranged from having a strong surplus to showing a small deficit.

Membership for FY 2017 was strong, with a total of 107 members by year end. The chart on the right shows annual membership revenue, which has fluctuated with a slight downward trend.

The chart below shows AAAP reserves over the past 12 years. They grew over many years to very high levels relative to the annual expenses of the organization. In recent years we have invested more of those reserves into our program and facility.

Our cash balances and cumulative reserves are close to $15 thousand, equaling roughly two years of the association’s total average annual expenses from FY 2013 through FY 2017.

Please let me know if you have any questions about the report.

Posted in October 2017, Sidereal Times | Tagged | Leave a comment

The Cycle of Eclipses

Posted on October 3, 2017 by ST Editors

by John Church

Many of my fellow AAAP members will have heard of the “saros”: the 18 years, 11 and one-third day cycle when eclipses of the sun and moon recur with nearly the same circumstances. To be more precise, the cycle lasts 6,585.3211 days. The reason that eclipses recur like this is that in this period there will have been 223 synodic months (new moons or full moons), 239 anomalistic months (returns of the moon to its perigee or apogee, its closest or farthest distance to earth), and 242 draconic months (returns of the moon to a particular one of its nodes, the two points where its path crosses the ecliptic every month and eclipses can happen if the sun is nearby.

This cycle was known to ancient skywatchers; the word “saros” is derived from the Sumerian “shar,” meaning “multitude” or “large number.” Its usefulness lies in the fact that if you see an eclipse of the sun or moon of a particular kind, i.e. total or partial and lasting a certain length of time, there will be a similar one 18 years, 11 and one-third days later.

Therein lies two difficulties. The major one is that in the extra one-third of a day, the earth will have rotated 120 degrees of longitude eastward from where you were the first time. In the case of a lunar eclipse, these are visible over such a large area that you might be lucky enough to see both of them without having to travel. In the case of a solar eclipse, as we all know, these are only total or annular in a very restricted path, but there is still a significant area where one can see at least a partial eclipse.

If one is patient enough to wait three whole saroses (a so-called “triple saros” or 54 years and about 31 days depending on how many leap years intervened), the same kind of eclipse will come back to roughly the same part of the earth where you were the first time. However, because of the extra days, the earth will now be in a different part of its slightly elliptical orbit and a different distance from the sun. The sun will also be at a different altitude, if visible at all. So if it’s a solar eclipse, the path will not be exactly where it was before and the duration will not be the same. However, in most cases you will still see something similar, if you are not clouded out.

I have been lucky enough to have seen several solar eclipses of about the same character separated by these intervals. The attached images, taken from https://eclipse.gsfc.nasa.gov/SEpubs/5MCSE.html (Espenak and Meeus, public domain), show these eclipse paths. I have added red dots to show where I was when these eclipses happened.

The individual saros series are in the upper left. If the series number is the same, then these two eclipses are in the same individual series but separated by one or more 18 + year intervals. A series starts with a small partial eclipse near the north or south pole and slowly progresses southward or northward until no more eclipses take place in that series. The only solar eclipse series currently active are those numbered from 117 to 156; the others occurred before or will occur after the 5000-year period of the maps.

1970 eclipse
click on photo to enlarge

The “x’s” in the diagrams are the subsolar points (where the sun is in the zenith) at the time and place of maximum eclipse, which is shown by an 8-pointed star. The Earth is oriented to show the full eclipse path, with the subsolar point always on the “meridian.” The dotted lines are where there is a 50% partial eclipse.

The first eclipse of which I have any reliable memory was the annular one of 1951. In Virginia, my father and I got up before sunrise and went to a park where we might have seen the annular phase. However, it was cloudy. Later on it did clear up and we saw a large partial eclipse.

The next one was in 1954, which was total farther north, and it was clear in the morning. We did see something like a 70% eclipse, which was still quite nice. I could not know then that in 1972 I and my growing family would see the next one in the series in New Brunswick, Canada as a fine total eclipse through high thin clouds. The one in 1954 was near the beginning of its track and the one in 1972 was near the end of its track, which made it possible to see both of these from the eastern part of North America despite the 120-degree turn in the earth mentioned earlier for two eclipses separated by one saros.

The first total I ever saw was at Old Point Comfort, Virginia, in March 1970 in a clear sky. One “triple saros” after this, there will be the eclipse of April 2024. I hope to be lucky enough to see this one as a total also, to complete one full triple cycle of totals.

In between these two was the large partial one in 1963 when I was a graduate student in Wisconsin. Again, I had no idea that I would see it as a superb total this August in Oregon with a group of club members. In a sense, this does complete a triple saros, but without having seen them both of them as totals.

Two other eclipses of memory were the annular (but nearly total) one of 1984 and the annular of 1994. I and my two sons were in Virginia in the central path in 1984 but were clouded out of the central phase. (Later on, of course, it cleared up.) The notable thing about this eclipse was how it suddenly got very dark for a few seconds and then as suddenly lightened up again. The cattle in a neighboring field were startled and vocalized.

In 1994, my workplace in Piscataway took a break around lunchtime on a Tuesday and we were treated to a very large partial. Some AAAP members may have seen this as a long-duration annular elsewhere. If so, it would be interesting to hear their stories about it, or about other totals that they may have observed.

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Biosphere 2

Posted on October 3, 2017 by ST Editors

by Prasad Ganti

On a recent vacation to Arizona, the Grand Canyon state, I had the opportunity to visit Biosphere 2, near Tucson. It is a futuristic looking structure containing a sample of ecosystems found on Earth. Used currently for conducting experiments on the impact of climate change on an accelerated timescale, it was once a habitat for a voluntary group of people who lived in its sealed premises for two years from 1991 to 1993, as part of an experiment on the sustainability of life in such a closed, and scaled down ecosystem.

My first curiosity was why Biosphere 2 ? Where is Biosphere 1 ? I found that our planet Earth is Biosphere 1. The giant set of ecosystems sustaining life all around us. Millions or billions of members within each of the millions of species. It remains in harmony but for some extinctions from time to time, some as part of nature, and some forced upon by an intelligent specie called Homo Sapiens or the human beings. Other than quick experiments which can be done to predict how Biosphere 1 will behave in future, Biosphere 2 also serves as a laboratory for habitats which need to be setup in mankind’s quest for colonizing planets or moons in the future. To test the viability of different life support systems.

I recently read the book titled “The Human Experiment” by Jane Poynter who was one of the Biosphere residents for two years. An interesting experience and some interesting observations. I am not sure if I would give up two years of my life to stay in such seclusion, but this team did endure a lot to become the guinea pigs. There were some controversies regarding the experiment itself, but overall, it was more than a glass half full kind of scenario.

The Biosphere 2 was financed in its entirety of a quarter million dollars by Ed Bass, a Texas billionaire who is labelled as an ecopreneur, an entrepreneur who deals with ecological ventures. Putting his inherited wealth to good use, he contributed immensely towards the study of ecosystems. Covering an area of little more than three acres, it was architected as a series of space frame based structures. Space frame is a mesh of lightweight metallic bars, interspersed by glass. Double panes of glass sandwiching a shatter-resistant plastic film. It was constructed as the tightest building on the Earth. Once sealed, the atmosphere could not escape into Biosphere 1, nor anything could get in. It was tighter than the space shuttle. An engineering marvel in support of science! The pictures below were taken from my iPad pro.


The entire complex contains a habitat, a rainforest, a savannah, a desert, a marsh, an ocean, and some land for agriculture. The habitat contains living quarters for the inhabitants. Agricultural land is for growing crops for sustaining life within the sealed system. The ecosystems have been built with great care by importing the plant and live species from around the world. There are lot of equipment in the basement to control the environment in different parts of the Biosphere 2. The vast gamut of machinery is dubbed as Technosphere. There are sensors placed all over the Biosphere 2 which feed into the Technosphere below.

Once the Biosphere 2 is sealed, the pressure inside would fluctuate wildly as changing temperatures caused by changing seasons and the sunlight falling through the glass, causing the air inside to expand and contract. The Biosphere 2 needs lungs to breathe. For the Biosphere’s lungs, a round steel chamber the size of a large ice rink with a neoprene roof, was attached to the side of the Biosphere. The flexible ceiling would act like a bladder, rising as the pressure increased, and sagging as the pressure lowered. I could not think of such a need or a contraption earlier.
The team which lived inside for two years, prepared for a life in seclusion. First by being on a boat in the middle of Indian ocean for a month or so. And then staying in the Australian outback for about a year. Far from any civilization or its conveniences, it was similar to how small groups of people live in space like the Russian Space Station Mir or the International Space Station. Or in the research labs in Antarctica. Although they did all the chores like growing food, cooking, cleaning, recycling, operating the machinery by themselves, they did have gadgets for cooking, laundry etc.

The team grew starchy foods like white potatoes, sweet potatoes, rice, wheat sorghum etc. The variety in crops made the land use sustainable. No fertilizers or chemicals were used as they could contaminate the atmosphere and could make life unbearable. They were constrained in the amount of meat they could eat. They started with some livestock and nothing else could come from outside. The cattle had to multiply before being slaughtered for meat. The inhabitants had to grow all the food for their needs. As a result, they became skinny, often craving for all the nice food which the waving visitors were eating beyond the glass walls. There were some conflicts within different members of the group from time to time. It is to be expected from a small isolated group of people living together for extended periods of time. A simplistic lifestyle reminiscent of our forefathers! The experiment resulted in some species becoming extinct, which was to be expected, and more importantly proved that human beings could live.

There were a couple of occasions when there had to be an external intervention. Jane Poynter cut her finger very badly to the extent of dismembering. One of the inhabitants was a doctor. He could not do much. She had to be carried out to a hospital. She was back after a few hours. Second time was the reduction in levels of oxygen. It was later found to have been caused by concrete, which breathes in oxygen long after its curing is over. Oxygen was pumped from outside to make up for the loss. Other than these incidents, there was near perfect isolation.

There are enclosed systems like rainforests in other parts of the world like Gardens by the Bay in Singapore, but such a diverse set of ecosystems, along with life support systems all under one roof is really unique. Biosphere 2 is not sealed anymore, there are no more human experiments, only ecology related experiments conducted by visiting scientists. Administered by the University of Arizona, it is an excellent science facility which tourists can find very interesting.

Posted in October 2017, Sidereal Times | Tagged , | Leave a comment

Trifinder Trouble

Posted on October 3, 2017 by ST Editors

by Ted Frimet

It’s the end of the world as we know it.

A brief recapitulation on the status of my cats endeavor to improve the sighting accuracy of my 12 inch dobsonian telescope by way of collapsing his cat tower onto my behemoth. The cat survived. And the dob has good views. Good news, all around. As for the horizon challenge laid out by a member of another club – I am at the precipice of understanding, by way of an 80 year old scholar, that given the several concentric lines that represent each passing billion year eon, that our shared astronomical sight lines extend from one point in a horizon, to another. As a line is drawn, from the observers point to the observed, as a geometric chord across the curvature of our graph, the area under the curve is my horizon.

Hence, my answer to the esteemed gentlemen of other club grand stature is that I now proclaim “horizon” to be a relative term. Did anyone take a breath? Did you want some dressing with that word salad? Wait for it. One more verbal equivalent of the hand jiggle to get all the wiggly wigglies out!

If you fast forward to the end of this essay, you will find an embedded cat meme, produced by yours truly. I would rather you get the message, other than the fortuitous laugh. The message being, “please spay or neuter your pets”. This message comes to you, across a vast emptiness of space and time, experienced by myself, and my recently adopted feral family of one. This cat, although not personally reared to be a telescope destroyer, has recently chucked up a couple of hairballs in protest of my dobs’ temporary location in her lioness lair. However, to be fair, she is good company, and we have changed her name from “Hissy cat” to “Priss” of the Hunger Games variety. Could not ask for a better companion while hunting down faint fuzzies.

Your world is about to come to an end. And I don’t mean to relay any confidence, that this article dated September 23, 2017 has anything, coincidental to share with the end of world phenomenon espoused by others. They don’t write here, and I don’t credit ‘em being credible. Besides, I am hardly on the cusp of credibility, myself. Here is what I had to say on that: After careful calculations with a rubber band, and a ruler, I have prognosticated that a 28 meter wide asteroid will impinge operability of the ISS composting toilet, creating a causality “Do – Loop”.

No, sincerely – the only astronomical item that might coincide with the end of world event, is Asteroid J2012 TC4. The Apparent Magnitude (as seen from Earth) should be just under 22, for today. It will be closest on October 13th. As it approaches Earth with 0.10 lunar distance, the gravity will accelerate the asteroid, increasing its APMag from 16 to 13. Making it a decent target for amateur level scopes.

Unfortunately for AAAP members, the asteroid will be either below the horizon, at peak magnitude, or below the tree line. The end of the world however will have a vantage point, no matter where you observe from!

Wiggles done. Engines engaged. Warp drive committed. And now…the end of the world: PUT AWAY YOUR TELRAD. Ah got your attention. At this years Starquest we happen
across Dr. Peter Wraight, and his hand developed and simply sublime construction of astronomy grade binocular viewing devices. After being completely blown away by the reflective mirror he employed in one, and the 100mm lenses from another, I am pleased to say that you no longer have to crane your neck to get a good view of the sky thru binoculars. Could this almost be too good to be true? Well, yes. There is a slight bit of craning to be done, however, not what you would expect from Dr. Wraight.

Peter has developed a finder. You decide on a target in the night sky, and pick two guide stars of magnitude 3 or brighter. You then can either calculate, or use his NGC guide book (with pre-calculations) to obtain, a reference angle. He has written program code to doggedly convert right ascension/declination into his new Trifinder system.


As pictured above on our finder disc, two sides of a triangle (not shown), one leg ends at one guide star, the other leg – the other star. And at their vertices you will find your target. Easy Peasee. And if you didn’t get it the first time, the vertice angle is formed by the two legs. On Peter’s finder, one leg is calibrated and can span up to 18 degrees with illuminated dots for each degree, while the other is represented by a small illuminated line pointing toward three illuminated dots and spans 22 degrees. The finder incorporates a simple lens and a semi reflective perspex disc to effectively project an infinity image of this “triangle” on the sky above. Move the dob so the end points are on the guide stars, and Wa-La! – target acquired at the vertice. The seeing is the believing! I’d write more on The Trifinder, however, we should all encourage Dr. Peter Wraight to publish his work, on the web for all to know and tell.

Meme as promised:

Posted in October 2017, Sidereal Times | Tagged , , | Leave a comment