From the Director

Rex

 

 

 

by Rex Parker, Director

Proposed Amendment to AAAP Constitution.  The Constitution and By-laws of AAAP have provided a solid framework establishing the purpose and structure of our organization that has lasted 55 years.  We’ve been able to grow and adapt to the many changes in amateur astronomy and the role of the club in the eyes of our members and the public. We’ve been guided and maintained by a five-member Board of Trustees, comprising the Director, Assistant Director, Treasurer, Secretary, and Program Chair.

The ability to draw upon the ranks of members to fill key leadership positions in the club is essential to our future.  In recent years the importance of the observatory and public outreach has become more apparent, and this has led us to re-evaluate the organizational structure. Heretofore, the Observatory Chair and Outreach Coordinator positions have been appointed by the Director, and as such they do not have Board authority or voting privileges. The effectiveness of these positions and the prestige and recognition of the roles would be enhanced by making them Board-level positions. Then they would be elected by the membership each year as are the other officers.  A proposal to institute these changes was made last June and reviewed by the Board in November last year. It was agreed by unanimous consent to initiate formal Amendment proceedings to make the relevant changes in the Constitution and By-Laws.  For efficiency, an additional change is being proposed to raise expenditure authorization “for equipment or observatory improvements of up to $500” (formerly $200).  Other minor changes will be made for accuracy in the document.

This article serves as formal notice of the Amendment proposal, as spelled out in Article V: Amendments.

Amendments to the Constitution and By-Laws of AAAP may be proposed by a majority vote of the general membership at any regular business meeting, provided that a quorum is present as provided for in the By-Laws, or by a vote of the Board of Trustees.  Before any amendment shall be adopted, the amendment shall be discussed at regularly scheduled general membership meeting and a written notice of the proposed amendment shall be distributed to all members.  No amendment shall take effect unless it receives a majority vote of the total membership.  Voting by mail or e-mail is permitted.

The current full version of the Constitution and By-Laws can be downloaded from the website, http://www.princetonastronomy.org/club_by_laws.html.  At the January 9 meeting the Amendment proposal will be discussed, and if it goes forward a vote will be held at the February meeting.

Back home again in Jersey.  After an amazing 3 week trip to Thailand and Cambodia in December, it is great to be back home in New Jersey. That was a cultural and archeological trip, not science, and so I very much look forward to talking astronomy with you on January 9 at Peyton Hall (7:30pm) for our first meeting of the new year. See Ira’s article below for background on the guest speaker.

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Posted in January 2018, Sidereal Times | Tagged , | Leave a comment

From the Program Chair

By Ira Polans

The January meeting of the AAAP Is on the 9th at 7:30 PM in Peyton Hall on the Princeton University campus. Parking is available in the lot across the street from Peyton Hall.

Michael D. Lemonick

Michael D. Lemonick

The talk is by Michael D. Lemonick on his book “The Georgian Star: How William and Caroline Herschel Revolutionized Our Understanding of the Cosmos”. While William Herschel is mostly known to the public for his discovery of Uranus, this is one of the least important contributions he made to astronomy. In fact, working with his sister Caroline, he single-handedly invented the modern science of astronomy, along with discovering infrared radiation—accomplishments that are all the more remarkable given that he had no formal training in astronomy or science but was instead a (very accomplished) professional musician for the first half of his life

After the meeting there will be a book signing.

There will not be a meet-the-speaker dinner this month.

We look forward to seeing you at the meeting!

Posted in January 2018, Sidereal Times | Tagged , , | Leave a comment

December 12, 2017 Meeting Minutes

by Jim Poinsett, Secretary

Minutes of the December 2017 meeting of the Amateur Astronomers Association of Princeton

• The meeting was called to order at 7:30 by Michael Mitrano standing in for Rex Parker.

• Bill Murray gave a presentation on the life of Charles Messier.

• Treasurer’s report, Astronomy Calendars will be available at the next meeting and membership reminders will be sent out in January.

• Observatory News

      o The water is turned off, bring your own if you want.

      o The focusing tube on the Hastings is being worked on so the telescope is unusable. A break in the weather is needed and hopefully the work will be done by the end of January.

      o There was lots of interest in electronic assisted astronomy, the event at the observatory was well attended. A decision needs to be made to have the new video camera ready for the next observing season.

• Outreach – the first event has been posted in the new outreach calendar, Feb 21 – intro to stargazing.

• There being no further business the meeting was adjourned.

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

Winter use of the observatory

by Dave and Jennifer Skitt

The cold weather has set in but that doesn’t mean the observatory can’t be used to catch that elusive asteroid or your favorite winter galaxy or star cluster. Here are a few considerations to keep in mind before you head out.

First and foremost is to dress appropriately for the cold temperatures. Dress in multiple layers (more than you think you’ll need) and bring along a hot beverage and snacks to keep your energy levels up. There is a small heater in the control room that can be used to keep warm; just be sure to turn it off before leaving. Also, having a willing and devoted spouse, friend or fellow observer accompany you is highly recommended.

Second, please consider that any significant snowfall will affect how you access the observatory. The park’s main entrance gets closed and locked much earlier now and our typical access from Bear Tavern Road may be plowed in. You may need to shovel an opening to reach the locked gate. Furthermore, the parking lots by the soccer fields do not get plowed, nor does the gravel road by the campsites. Therefore, a vehicle with a high stance and all-wheel/4-wheel drive is highly recommended.

Next, thick/compacted snow on the control room roof will impede opening the roll-off-roof. However, light/fluffy snow can be simply (but carefully) brushed off using the broom stored in the bathroom. While there is a snow shovel in the observatory, it should not be used as it can all too easily damage the roof surfaces.

Lastly, the water to the observatory has been turned off and the pipes and fixtures drained to protect their integrity. If used, the toilet bowl can be manually flushed using water you bring with you in a five-gallon bucket. Pour the water rapidly into the bowl to flush and be sure to replace the pink RV antifreeze in the bowl before you leave. There is a supply of antifreeze in the bathroom; about two cups added to the bowl is sufficient. If you happen to use the sink, please add some antifreeze to the drain trap as well.

While this may seem like a lot of effort to go through for winter observing, remember that the telescopes are already there, already set up, aligned and waiting to be used. Use them as you would on any warm summer night. Happy New Year and happy observing!

Posted in January 2018, Sidereal Times | Tagged , | Leave a comment

Hastings-Byrne Refractor Update

by Dave Skitt

AAAP member Tom Swords, in consultation with John Church and with my assistance, is currently working to improve the connection of the focuser for the Hastings-Byrne refractor to the tube assembly. We have become aware that the focuser attachment screws would loosen over time, allowing the heavy focuser to wobble. While the views through this F/15 refractor are still wonderful and a de-focused star test shows no noticeable distortion of the airy disk, misalignment of the focuser to the optical path is typically not considered ideal. We believe our efforts will not only correct the attachment issue, but also improve the optical alignment and future ability to collimate the telescope.

The first task, after removing the focuser, was to square up the end of the steel tube. As John recounted, he and Gene Ramsey were reluctantly forced to shorten the tube when the original, worn out, focuser was replaced with the current one some years ago. In the process of shortening the tube, a slight deviation in the cut was inadvertently introduced. Tom and I identified the deviation and Tom gingerly removed the protruding metal with a small grinding wheel (Photo 1).

The preliminary result has been to move the optical center of the focuser closer to the center of the lens cell. In Photo 2, Tom’s finger is pointing to where the center point was falling prior to squaring, and the red laser dot is where it is now pointing with the focuser only temporarily attached in the newly squared tube (Photo 3). Further refinements, described below, will likely bring the final alignment even closer to the true center of the lens cell.

Since the historic steel tube is known to have a very slight taper from front to back, a small gap was likely introduced between the new focuser’s outer diameter and the tube’s inner diameter when the tube was shortened. Tom is currently in the process of experimenting with shim material of different sorts, widths and attachment methods to find the best match to remove the wobble the focuser was experiencing. After temporary placement for final adjustments, the existing holes in the focuser will be drilled and tapped for larger screws with increased gripping surfaces.

While the cold weather has delayed further work on the project at the observatory, Tom has used the time while the focuser has been in his shop to perform some additional maintenance. Photos 4 shows the freshly cleaned and polished coarse focus rollers and new rubber tension spring washers. Photo 5 shows the freshly cleaned and lubricated fine focus assembly. And finally, Photo 6 shows the freshly painted interior surface of the drawtube.


We hope to have the Hasting-Byrne refractor back in operable condition in the next few weeks. If you have any questions or comments about our work, please feel free to reach out to Tom, John or myself.

Posted in January 2018, Sidereal Times | Tagged , | Leave a comment

Bare Naked Ladies

castor and pollux exposed

by Ted Frimet

No, we haven’t changed the sex of our favored Gemini twins. This title has been haunting my mind, for a few days now.

The Father of Advertising, David Mackenzie Ogilvy bombards my mind with memories of past reads. Among more discrete topics, Ogilvy wrote that sex sells. Well, only that is, if the subject is relevant to that which you are selling.

I could have tried to sell you snake oil, however Draco isn’t in my eyepiece at the moment. And snake oil, I presume isn’t too tasty. Nasty stuff. Very few repeat customers. Hence the title. No snakes, just bare naked ladies.

Oh how, just how do we save the title and write a smidgen of Astronomical significance?

Ah-Ha! Join me on a short journey, where we shove off to a near death experience. Or rather, a Near Earth Object (NEO) that was categorized as potentially hazardous. That’s WordSpeak for ye old end of days. A story, charred down to the boney essentials and filled with magnitude and parallax. Starring of course, a bare naked comet, better known now-a-days as Asteroid 3200 Phaethon.

Phew. The essay that follows is shorter than that intro. Thank the heavens!

I was sitting on the couch a few weeks back, lamenting the clouds that precluded us from enjoying the marvels of the yearly Geminid meteor shower. Yes, a few days had passed. But I hang onto my lamentations. They become the core excuse for not hauling out my 12 inch dob, into the backyard on the least stable viewing nights. Then some smart bloke wrote about the Ursids. Some consolation, I thought! As a newcomer to amateur astronomy, I was pretty certain that Ursid would not be the bees knees, and leave me sulking for another 12 months while waiting for next years Geminids.

Let’s take this back to the couch, again. Perfecting the art of couch potato, remote in hand, my hind brain motions to battle with my forebrain. And won. Out popped a reminder that this evening 3200 Phaethon, a NEO, was an able and willing target. A quick check on regional weather ( that’s fancy astro-speak for looking out the window ) showed the promise of a clear night. Of course, a promise of a clear, stable atmosphere to an amateur astronomer almost always leads to broken promises, and cloudy nights. A sheen of clouds rolled in with hardly any notice. Leaving me to whimper. sigh. Cloudy sky. What to do?

Some of you are aware that I have been cultivating data on the variable star Algol, from minimum to minimum. This continues to be an ongoing project, with 39 out of 69 data points still required to be filled. I’ve been requesting telescope time on those evenings, where and when I can fill the gaps in my data. The two scopes that have been successfully tasked are the fourteen and seventeen inch telescopes at the Dark Sky Observatory (DSO), located in North Carolina. A quick check of my spreadsheet, shows that I have imaged Algol, during 10 (minimum to minimum) sessions, since November 16th, on both DSO-14, and DSO-17. Being fond of the more diffuse star light results of DSO-14, I decided to capture Phaethon, status quo.

Based upon previous observational success with a smaller 28 meter asteroid, J2012 TC4, I cast my line out to 3200 Asteroid Phaethon. I bait my hook with a 10 minute interval, 4 seconds exposure, for 60 images. The proverbial float on the water bobbed up and down. Asteroid on the hook – I cautiously check the first 8 images. Viewing them in quick succession I quickly established that the asteroid was moving out of frame. This was moving much too quickly to produce a viable video. I cancelled the remainder of my Skynet observation. I resubmitted anew at 30 second intervals. Voilà.

Asteroid Phaethon is the remnant of a comet that produced the Geminid’s. Kevin D. Conod, writing for The Star-Ledger composes his article, “N.J. Night Sky: Shooting stars from an asteroid” (updated Dec 9; Posted Dec 9) and can be read here: https://goo.gl/7b5YtK Conod writes briefly to remind us that the Geminid’s parent is Phaethon.

And this now lays a foundation of future thought, for this amateur, that I should pay more attention to asteroids that pass thru other cometary debris fields. And pay homage to the bare naked ladies – those asteroids stripped of their cometary nebulosity and consider them as the source of my yearly visual delights – our dazzling meteorite showers.

Here is the final video of Asteroid 3200 Phaethon:

Some final thoughts and thank you’s. There was a technical error in my first video, where I confused apparent magnitude with absolute magnitude. The error occurred to me after reading a critique by Joe Stieber, a fellow member of UACNJ. I am equally gracious for our AAAP Club President, Rex Parker, taking the time out to vet the video, and make recommendations that were equally helpful. And a shout out to our Observatory Chair, for an early distribution of the asteroid video. And for discovering at a late hour, a broken link on YouTube. Fortunately, the only sacrifice was the 230 or so, original views on the first two published movies. The current count is now 30, views and that can grow, going forward.

Below you will find some of my commentary, on some of the quirks of remotely imaging NEOs as I reached out to Joe, by way of UACNJ posts:

The creator may be in the structure, but the devil is still in the details!

Thank you, for refocusing me – on Asteroid Phaethon.

I rechecked the ephemeris data with the NASA Horizons web interface. I plugged in the longitude and latitude of the DSO-14 telescope location. And the AP Magnitude comes back at 11.8, across the board.

My photometric tool must be measuring “absolute magnitude” and not apparent magnitude.

Stellarium displays an absolute magnitude of 14.60 for this asteroid.

So, the data I measured, as an overall average of 13.94, isn’t too far off the mark for an amateur.

I must make an effort to be clear on “absolute” measurements, versus “apparent”.

After this email, I will make the necessary correction to the video’s text.

I set the telescope exposure time for 4 seconds, at 30 second intervals. So the 60 frames should represent about a half an hour.

However, DSO-14 is a shared resource, and I have lower priority. The reality in time management pushed this to an hour observation, over-all.

As for the “jumps” in magnitude – they are as recorded, and I rechecked four frames. A closer examination might show that lower numbers corresponds to stars being in the field of view. Or not. This will have to wait until I have much more time for evaluation, and a second pot of coffee! (side note to self – use the small mug!)

On the face of it, however – the data is real, and my opinion based upon the data is that the asteroid is not a uniform object for reflectivity.

As for the “orientation” part of the video – showing the asteroid in the vicinity of Pegasus, I rechecked with Stellarium and I am still in the ballpark, so to speak.

When I plugged in the long/lat for the telescope, incorporated my start time, and date and looked for Pegasus – I found the asteroid where I expected it to be.

If there is a discrepancy, it probably comes down to parallax. When observing near earth objects, recording the origin of the telescope is paramount, to getting correct on screen observations.

DSO-14 is located at:
36.253 Latitude
-81.415 Longitude ( or 81.415 W )

The time of the first image taken was on:
December 17, 2017 02;08:12 UTC, which is December 16th, 2017 21:08:12 EST.

I was going to scribe out the date-time groups, however, for brevity sake, I’ll list the first and last data points.

The date-times are UTC.


Happy New Year, and Clear Skies for All !

Posted in January 2018, Sidereal Times | Tagged , , | Leave a comment

no more buwwets

by Ted Frimet

how much wood

could a woodchuck chuck

if a woodchuck could chuck wood ?

I bring you tidings of a final essay, as I have spent all of my Shekels from 2017. And have no coin left for another asteroid. I probably have done as much as I can, given the precious tools that were lent to me, by educators, and club members alike.

While researching Elf on a Shelf, I stumbled across Mench on a Bench. I knew it. I should have bought one. Or maybe, I should never have touched the elf. I heard that if you do so, the magic just runs out of ‘em. Or as Bugs Bunny once said to Daffy Duck, “hey doc, No more buwwets ?”

I took a keen interest in a website that manages data, by way of a NASA grant, on minor planets. Asteroids, I have learned, are sometimes referred to as minor planets. So full of ego, was I, to continue to read that a recently captured asteroid, temporarily labeled YY897E1, was observed in the deep of space on not less than four occasions. And was rated at 100% desirable for more data. I took the bait. Yes I was hooked, and knew that I would tire on the line. The magnitude, you see, as at 21.6 v. And I had my doubts that I could find an object that faint.

I broke down the NEO confirmation data into four blocks, of 10 minutes each. And asked for 4 seconds exposure 30 second interval images. Not enough bullets,  for ‘ol Bugs. The stellar limiting magnitude, if memory serves me correctly, cut out at around 17. To add mischief to miscalculation, the telescope release times were delayed, and did not match my ephemeris data. I, as Mr. Hopeful (a tip of the hat to one my indoor cats, that is Ms. Hopeful, aka Big Pussycat, aka Maybell – around dinnertime) did spy upon three potential variances in the image cache. A pot of coffee later, and with Digital Sloan Survey in hand, two of the hopefuls were stars – and the remaining minor trailing spark of hope was written off as a high speed energetic particle of other worldly origin. (Ok – maybe it was just from our stratosphere. sigh.).

Last man standing with a few coins in hand, I turn my attention to a list of asteroids for 2018 that would make good mention. And fell in love with 1362 Griqua. Wiki records her as 28 kilometers across. That is 1,000 times the diameter of J2012 TC4, imaged back in the day, when I was drunken with Skynet currency. I had my marching orders, now.

After experiencing the elusiveness of YY897E1, imagine my glee, when Griqua lit up my screen! How would I present this object? Well, two ways of course! Once as static, Griqua smiling back to you at center of screen, while the surrounding stars flew by. And once again, as Griqua sailed thru the night sky, leaving her starlets, motionless in awe.

And then I saw the discrepancy. There was an unintended time delay between image 0 and image 1, of 24 minutes, plus some. Not the two minute interval I had hoped for. I asked the Mench for help, but he simply sat there, on the bench, with nothing to say. What could I do ? Of course, ask the Elf to speak to Mr. Claus, on my behalf! However the Elf was out of magic, and her lines of communication had been cut. No direct line to Santa. Beans!

How much wood can a woodchuck, chuck ? is my euphemism for how fast does an asteroid travel thru space? I couldn’t quite wrap my noodle around ideal calculations with J2012 TC4, or 3200 Phaethon (recently imaged) for linear velocity. However, NASA had already calculated the diameter of Griqua at 28 km, and I knew the time frame from which I took pictures. Teeming with errors, I decided to not use Julian calculations (which report down to fractions of a second) and used vernacular minutes and seconds to limit precision within the boundaries of acceptable error.

Measuring the diameter of each asteroid in frame, I arrive at 8 pixels, rounded due to errors in measurement. So, 28 km = 8 pixels. Taking my time, I arrive at the following:

I have recorded 26.13 pixels from one asteroid location (image 1), to the “last” (image 7), over 765 seconds. Griqua is 8 pixels across, in my image. 26.13 / 8 = 3.266 Griqua units.

28 km * 3.266 = 91.5 km

91.5 km / 765 seconds = 430 km/hr

Now, back to my woodchuck:

There was a jump in imaging between my first and second frame resulting in:

1,445 seconds elapsed between a distance of 48.88 pixel distance (center to center).

48.88 / 8 = 6.11 Griqua units.

6.11 * 28km = 171 km

171 km / 1,445 s = 426 km / hr

Griqua, it would seem, and of course, only at first blush, travels around 430 km per hour. Prepare yourself as the mensch on the bench, just established a toe-hold in the boundless world about the elvish kindred, by virtue of chucking wood at the void. At 430 km / hr, that’s some pretty fast wood.  

For the linear velocity portion of the video skip ahead to time frame 2.25.  For telescope exposure/filter times click here.

Happy New Year to all club members!

Posted in January 2018, Sidereal Times | Tagged , , | Leave a comment

The perfect machine – Ronald Florence

by Prasad Ganti

The book “The Perfect Machine” is written by Ronald Florence. A fascinating book about the design and construction of the 200 inch telescope at Mount Palomar during the years leading up to the second world war and its immediate aftermath. George Hale, known for his research in solar astronomy, championed the telescope right from the proposal stage all the way into the advanced construction of mirror and the mounts. He died just before its completion. New York Times urged that the telescope be named in his honor.

George Hale was known for his earlier efforts to build the big telescopes for the Yerkes and Mount Wilson observatories. The 200 inch at Mount Palomar was a logical successor to the 100 inch at Mount Wilson which Hale had built. Hale also had other impressive credentials, as a co-founder of Caltech, an officer of the National Academy of Sciences and the National Research Council, and the founder of Journals of Astrophysics. Hale conceived of the design, sold it to the scientific community and other stakeholders at large and got the funds needed to support the project. Lot of detail was written about the casting of the huge mirror. It really stretched the technology envelope of those times. GE first started off the mirror work with fused quartz. Fused quartz had such a low coefficient of expansion, that it would be far more efficient to grind and polish than plate glass. GE ran into trouble using this new material. Corning was assigned the task of casting the mirror. They used Pyrex which is basically borosilicate glass with extremely low coefficient of expansion. It required heating to very high temperatures. And then cooling in a very slow and controlled manner, called annealing, taking months to do so. The tolerances for the cast were very tight. Any imperfection leads to discarding the mirror disk and starting all over again. There were several attempts before the mirror could be finally cast.

Once the mirror disk was ready, it was shipped in a special freight train from Corning factory in New York across the country to Caltech in Southern California. Caltech had an optics and machine shop for grinding and polishing the mirror to its final shape. The train became a spectacle. People lined up all along its route to catch a glimpse. Several trains had to be held up or rerouted to provide clear tracks for the train with this special cargo.

At Caltech, the laborious work of grinding and polishing the mirror and fabricating the mount took several years interspersed by World War II. An equatorial mount was designed with a yoke holding the mirror and the yoke itself moving on a horseshoe bearing. There were three big motors to guide the telescope precisely. One for declining axis, tipping the telescope to be in the great yoke. One right ascension gear was for slewing the telescope, moving at relatively high speed when the observer wanted to point the instrument at new area of the sky. The third gear was for the slow-moving drive that would keep the telescope moving synchronously with the motion of the earth.

The mirror and the mount had to be transported on a huge trailer along a carefully selected route. New roads were laid to the top of Mount Palomar in San Diego county. The assembly of the mirror and the mount within the dome was an extraordinary engineering feat by itself. When it opened in late 1940s, it was the biggest telescope in the world and was to be for decades to come.

Overall, the project was a gigantic engineering marvel, no lesser than the Manhattan project or the construction of the Hoover dam. A grand intersection of physics and engineering. To this day, the Hale telescope holds its own against the newer ones with larger segmented mirrors and the simpler alt-azimuth mounts controlled by sophisticated computers.

Posted in January 2018, Sidereal Times | Tagged | Leave a comment