FROM THE BRONX TO BUZZARD'S BAY ------------------------------- John Pazmino NYSkies Astronomy Inc www.nyskies.org firstname.lastname@example.org 1999 November 30
[This article was written before the founding of NYSkies and is lightly edited from the original. The date is a nominal one set at one month after the AAVSO convention of October 1999]
Introduction ---------- The final meeting of the American Association of Variable Stars Observers of the 1900s was a overload of news, ideas, discussions, projects. It was topped by a revelation that astronomy is finally, finally, mainstreamed into the American civic and social culture. This year's convention, on 1999 October 28 thru 31, was held in Hyannis. Massachusetts, at the gateway to Cape Cod next to Buzzard's Bay. One impetus for moving the meeting there was the sharp increase over the last couple years of lodging costs in Cambridge-Boston, the normal seat of the AAVSO fall meetings. Hyannis in October is well past the tourist peak and the hotel rates slide to affordable levels, while in the Boston area they remain high all year round. This may be a continuing situation for AAVSO being that Boston is enjoying a round of prosperity. This can only enlarge with the opening of electric rail service from the City to that town in spring of 2000. Hence, AAVSO faces the prospect of shifting its meeting around Massachusetts -- its bylaws require its fall meeting to be within that state -- in a economicly enforced detachment from its homebase in Cambridge.
Getting to Hyannis ---------------- At any rate, Hyannis was easy to get to from the City. I went by Bonanza busline from the Port of Authority at 09:30 on Thursday the 28th of October. AAA's Dan Morgan and his friend Alice Snyder went to this meeting, too, on a later bus. Due to other engagements the two had to return to the City on Saturday the 30th, missing most of the sessions. The bus lurched out of the Port of Authority onto tenth avenue. It scudded along the Upper West Side, zigzagged thru Harlem, and hopped onto the Major Deegan and Bruckner Expressways. These vectored the bus into the New England Thruway and on into New England. Bonanza tried an airline trick; it showed an inflight movie, with rentable earphones, 'Out of Towners'! The screens, about letter-page in size, were hung under the luggage shelf at about every eighth row. They were quite bright and clear to see, even in the bright sunlight of that Thursday morning. The ride, with a halfhour reststop in Providence, took quite six hours. The short taxi ride from the Hyannis depot was a surprise. The driver asked why so many people were going to the Four Points Sheraton hotel this weekend; he had many trips there so far. I explained about the astronomer's meeting. The driver perked up. He was an amateur astronomer! We chatted about recent sky phaenomena. For him the August eclipse, at sunrise in Massachusetts, was clouded out.
The hotel(s) ---------- Upon arrival at the hotel I gave the driver a few EYEPIECEs. I brought along a supply of them for the litterature table during the convention. I went into the hotel to check in. No room for me at this place! The clerk checked and said I was booked for the Four Points hotel. So? Give me my key. Uh, sir, this is not the Four Points, but an other Sheraton property! The cabbie took me to the wrong hotel! The clerk fetched a second cab, noting to the company that I was left off at the wrong place. There was no charge for this extra ride. The hotel was on the far north side of Hyannis, well away from the tourist section and the waterfront. There was no easy way to travel about and the slate of activities was too full for any free time. So I confess I didn't get any view of the town. The hotel was deceptively small from the outside, like a village inn. In fact, it's about 150m on a side with a large courtyard and pool in the middle. My room was diagonally opposite the main lobby and meeting/dining rooms. I did get my walking exercise at this meeting. Presentations were slated for both Friday and Saturday, all day. Normally only Saturday has the papers and Friday has optional tours or informal meetings. My presentation was on Friday; Dan and Alice were on hand to hear it.
Hands On Astrophysics ------------------- The morning session on Friday was an intriguing one on AAVSO's major educational package 'Hands on astrophysics'. This is a kit of textbook, video, slides, charts, computer data and programs, and forms for teaching astronomy. The central theme is that astronomy, maths, physics can be taught and understood thru the medium of variable stars. The outfit is smartly assembled and packaged, and actually does present astronomy in a real and professional way. It is not a set of 'educational toys'. The intent was for schools to buy the kit and incorporate its materials into their science classes. Many of the speakers in this session were teachers and all gave lavishly favorable reports on their use of HOA. The one problem teachers -- or clubs and camps and other groups interested in astronomy -- had with variable star observing is that the students were battered by bad weather during the term. The data collected were too scanty for any analysis and study. Stars could also be out of season, too dim, hard to locate among the field stars. HOA breaks these barriers by including the full database of some 45 stars selected for their variety of behavior and astronomical importance. There are some 600,000 datapoints for these stars. The discs, with data and the programs to read and manipulate them, are written for IBM DOS. Why DOS in the end of the 1900s? Simple. DOS is a thoroly adequate operating system capable of doing all the tasks needed in HOA. It is easy to program in (the code is QBASIC), and it runs on any IBM computer. Remember that schools typicly have computers from the mid 1980s! These rigs can not run Windows, let along Linux, and few are linked by network. It is rare that a school will continually update its computer facilities every couple years. The programs are the same ones downloadable from the AAVSO website, www.aavso.org, but the database is unique to HOA. The stars in the kit are all 'northern' stars. That's because the project was partly funded by NSF with the stipulation that the project be built for use in the US. However, for southern teachers, even in Hawaii (a US state, right?) AAVSO will toss in an extra disc with data for southern stars. While those who purchased the outfit were, to a man, enthusiastic toward it, the actual sales are, brrr, lousy. Since 1997 when HOA was first issued only 200 were sold worldwide. Why? The educational apparatus, particularly in America, has no place for astronomy. So far no school department or even one entire school anywhere adopted HOA as an integral part of its science offering. Only by the individual effort of a teacher is HOA brought into the classroom. And then the teacher faces a nasty expense. Out of his own pocket he must rationalize the price of HOA, $200. That's a bit too much for a teacher to lay out with little hope of professional reward from the school authorities. Lastly, HOA can not be spooned out straight from the box. It is not a canned sequence of presentations or a bunch of worksheets. The teacher must have the smarts in basic maths and science -- and computers! -- to read, select, tailor, and work the HOA materials into his class. AAVSO says no prior background in astronomy or science is needed. Nope. You have to know what you're doing to get the benefits out of Hands On Astrophysics.
Meals --- Friday lunch was on one's own nickel. Meals could be taken at places along the main highway in front of the hotel. There was a traffic control on the corner of the hotel, making it easy to get across the street to the shopping center and string of other stores on the road, I went to a pizza parlor for lunch on Friday and took supper at Cook's, a seafood joint, with other AAVSOers. Breakfast was just simpler to eat at the hotel's coffeeshop.
delta Cephei stars ---------------- The papers on the rest of Friday and all day on Saturday are too numerous to review them all here. I select several as highlights. Geoffrey Clayton presented his work at Harvard College Observatory in summer of 1999. He examined the photographic plates covering the Large Magellanic Cloud for delta Cephei, or Cepheid, stars. These stars have the amazing property that their luminous (actually the entire radiation) output is a one-to-one function of their period of light oscillation. This is expressed graphicly in the period-luminosity curve, discovered by Leavitt in the early 1900s. By assessing the illumination, the apparent magnitude, from a Cepheid star and clocking its period, we have two elements of the inverse-square law. The third, the distance, is found by algebra. However, the scale has to be calibrated by knowing the true distances to some of these stars. Astronomers have been frustrated over the entire 20th century for they have not yet measured for certain the distance to any one Cepheid star. HIPPARCOS tried but the Cepheids on its list were all too far away. Son-of-HIPPARCOS in a few years will for sure capture a true Cepheid distance. However, with the explosion of supernova 1987A in the LMC, the distance to that galaxy is now known very accurately. We do this by seeing the angular expansion of luminous shells around the supernova. The expansion rate and the constant speed of light yield the precise distance. Clayton hunted up delta Cephei stars on the old Harvard photos to determine their periods and illumination. These with the known distance to the LMC, generated new values for the luminous emission of the stars, and thus, rescaled the period-luminosity curve. The correction is crucial in cosmology. For the first time we can confidently fathom the distance to the remotest galaxies where delta Cephei stars are now being newly resolved. As a sidenote, Cepheid is sounded SEH-fay-id and Cephei is SEH- fay-yee. Cepheus, the constellation, is, of course, SEH-fay-yuss. Spike those EE-ee-EE sounds! David Turner related his experiments of monitoring the brighter Cepheid stars with just the naked eye. He studied delta Cephei, zeta Geminorum, and eta Aquilae and collected enough datapoints to draw up full lightcurves. These agree quite well with those produced by binocular observations. He found that he is more confident of his measures when observing the stars near the visual threshold, like in twilight or moonlight.
eclipsing binary stars -------------------- David Williams explained his work on 22 Vulpeculae, a binocular variable in our summer and early fall sky. 22 Vul is a G5 (yellow) supergiant with a B8 (white) main sequence star as its comes. The orbit is edgeon, making eclipses; the last one was in August 1999. When the white star is eclipsed it actually shines thru the yellow star's atmosphere! It does not blink out but gradually fades over roughly 20 days. This system is similar to epsilon Aurigae, but with far more frequent eclipses (eps Aur has a 27 year period). Williams did multiband photometry to probe the chemistry of the supergiant star and see how its material is layered.
therapeutic stars --------------- My own presentation was titled 'The therapeutic stars'. This was, by comments from the delegates, among the most fascinating papers they ever heard. It described the new children's hospital at Montefiore Medical Center in Norwood, the Bronx. The Association gave a couple starviewing and astronomy presentations to the present children's wing in the last two years. This year the hospital, already fundraising fro a new pavilion, was hit by an inspiration from those AAA visits. The new building will be a spacestation in which the children are explorers of the universe! In fact, it's not even called a hospital. It's the Carl Sagan Discovery Center. With pictures obtained for me by AAA's Antoinette Booth and discussions with Caralynn Sandorf, the project's director, I laid out the concept of the works. The entire experience of the patients is that of working on the crew of a gigantic spaceship travelling among the planets. The entry hall has a large rotating globe of the Earth, wall maps of the Bronx and the world, and ceiling model of the solar system. The patients, called cadets, live in cabins, not wards, and are issued an explorer's kit. This has, among other items, a ruler, navigator's compass, magnifying glass, boxes and jars for collections, notebook, pens. Their pajamas are space cadet suits. There is a central hall with internet computers for the cadets to receive news from NASA, ESA, and other space-related websites. Wall maps here plot the tracks of various spacecraft. In this regard, NASA may have its InterPlaNet running for the first of the new spaceprobes when the hospital opens in 2003. The cadets will get realtime news directly from the other planets! For those confined to their cabin the computers are at bedside on carts. The roof, in the second phase of the project, sports an observatory and planetarium. The scope, of about 400mm aperture, is fully automated. This reduces the fritter time to manually aim the instrument and helps cadets with mobility and dexterity constraints. The scope would be similar to a Meade LX-200. The planetarium may, just may, be a Zeiss projector. No promises here from Montefiore, but it is studying the Zeiss already in the Bronx. The Bronx has a Zeiss planetarium? Yes! It's in the Bronx High School of Science, just a K away along 210th Street. This project, so utterly of a nonastronomy purpose, is one crowning achievement of the 20th century for our profession. It crosses that final frontier yet to be approached elsewhere, the mainstreaming of astronomy as a viable and vivid element of culture. Astronomy has been featured as attachments to nonastronomy works in the past. We can look at the sky ceiling at Grand Central Terminal, the long-gone Luna Park of Coney Island, the Sputnik and Foucault pendulum at the United Nations, the mythical statues and murals of Rockefeller Center, the noon marker at the McGraw-Hill plaza, the sundials on College Walk of Columbia University. But never on Earth has astronomy been so intimately bound within an structure for so totally a nonastronomy purpose as the new children's pavilion at Montefiore. And it's in the Bronx! I rounded out the talk with some diagrams and statistics about the Bronx, which many delegates thought were plain too terribly funny to stifle the laughter.
counting sunspots --------------- Casper Hossfield detailed the miserable state of the sunspot counts in use today. He traced the history of the original Wolf sunspot counting method by Rudolf Wolf at Zurich Observatory. In 1882 the method was altered and called the Zurich sunspot count. Since 1882 thru a series of misreadings of the instructions and misunderstanding of the purpose of the sunspot counts, there arose two separate and misnamed systems. One mimics the old Wolf scheme, and is called either Wolf or Zurich count. The other follows closely the Zurich method and is called either Zurich or Wolf number. The result is that the modern observer may not know what he's doing and could be turning in counts under the one system while using the method of the other. This situation has caused much friction among sunspot observers over the years. Hossfield sorted things out as chair of the AAVSO Solar Division in the 1960s thru 1980s. He used as the baseline for historical sunspot counts the notebooks of AAA's Herbert Luft. Luft viewed the Sun by projection thru his 50mm tabletop refractor at 90 power for, at that time, over 40 years. Hossfield recommends small apertures, high power (to let the Sun's disc overfill the field), and a count of all visible spots. Some instructions, the wrong ones, at that time advised to ignore small spots and pores. Today the AAVSO numbers are far more aligned to the Zurich -- not Wolf! -- system and are a direct lineal continuation from it. This continuity of data allows for proper correlation among the past 110 years, about 10 sunspot cycles, of solar activity.
gamma-ray bursters ---------------- Mario Motta reported on the AAVSO gamma-ray burst alert project. At the 1998 fall meeting Dr Gerald Fishman of NASA explained about the prospect of home astronomers capturing the afterglow in optical wavelengths of a gamma-ray burst [EP 98 Dec]. At that time he thought it could be done but there were still too many unknowns in the behavior of these objects. Since then more baseline knowledge accumulated. It seems that there is a fighting chance that within a couple hours after the initial gamma blast there should be a residual optical flash. Moreover, this flash should be within range of home scopes fitted with CCDgraphs and automated control. Naively an observer so equipped would get a phone call from, say, AAVSO about a new gamma-ray outbreak. The observer would then fire up his rig and capture CCDgrams of the optical afterglow until it faded beyond his range. As exciting as this project sounds, so far it's hobbled by two factors. One is that the positional accuracy of the gamma-ray burst is still in those first crucial moments only within one degree. This is far too large for the typical home CCDgraph to search over when the flash may die out within minutes. The other is the method of sounding the alarm. Phone or email are out. The observer may not collect his email and anserfone messages for several hours. One suggestion is to issue beepers. Most beepers allow a one-line text message to be sent; this shows on the LCD screen of the unit. This text can be the [hopefully precise] RA-dec of the blast, a unique message saying that this beep is a gamma-ray alarm.
luminous graffiti --------------- The supper on Friday night was a shock! Now, mind you, if you be a remote reader, that I live and play in New York, the most antiastronomy place on Earth. Well, that's what you hear about the City from the lower tier of darksky authors. In the half kilometer walk with the other delegates from the hotel to Cook's, I was assailed by truly blinding and obnoxious lighting on the stores, road, carparks! It was tricky seeing the way with lights crazing up mu visual field! I toughed it out. The other delegates in the party were, of course, puzzled by my plight. Until I explained. Having grown so used to the wholesale eradication of excess illuminations from the structures and streets of New York, this experience in Hyannis was not normal anymore for me. Nor for any other astronomer from the City.
Spanish on Hyannis? ----------------- At the dinner, and all thru the meeting, we chatted with one special delegate from overseas, Jose' Iban~ez from Barboles, Spain. This was his first AAVSO meeting and it was a massive effort to get to Hyannis. Iban~ez speaks essentially no English at all. This was no problem at New York's JFK airport, where he felt at home with his Spanish. But from there to Hyannis via Boston the language barrier really hindered him. But he made it to the convention in one piece. You guessed it. AAVSO slid him toward me. Just because I sort of speak Spanish being that I come from the City and all that. Iban~ez's Spanish is a very pure, almost italian, dialect which I understood if he spoke a little slowly. Gradually a couple other AAVSOers tried their hand at Spanish and soon the burden of shepherding him at the meeting was distributed around. He gave a slidetalk, all in Spanish, on his view of the August 1999 solar eclipse and other astronomy activities in Spain. For the Q&A I figured, what the hell, and asked my question in Spanish. The audience roared! He also laid out for display some clear detailed photos of the Moon, which he taped together as a composite of the entire lunar crescent.
solar physics ----------- After the Friday supper at Cook's, we went back to the hotel to hear Dr Margarita Karovska. She gave a thoro headsup on current solar physics, of the sort our Carl Schurz Park solar observers would love to hear. Her emphasis was on the prominences and corona, the regions revealed in eclipses and H-alpha filters. One wow feature of her presentation were videos of coronal holes erupting from the Sun. They expanded in the thinning pressure to punch voids in the corona. Study of the motion and expansion of the these holes maps out the pressure and density in the corona. This is one of Karovska's specialties.
AAVSO reports ----------- The presentations continued on Saturday. Theodore Wales read Bob Evan's report on supernova searching. Despite the headline-grabbing accounts of automated or computerized supernova searches, the visual observer at his manual scope is still the prime method for finding supernovae. The fancy observatories do find the very faint ones but all the brighter ones are still captured first by the eye at the eyepiece. Dr Janet Mattei, AAVSO Director, gave her annual report. AAVSO membership is on a plateau at quite 1,100 with new entrants balancing out the dropouts. But AAVSO received in 1998-1999 reports from 1,500 observers. Of these, about 500 are actual members; the rest are outsiders who knew that AAVSO is the repository for variable star reports. The cumulative total observations in the AAVSO database reached 9- 1/2 million on 1999 June 12. In the period 1998 October to 1999 September AAVSO received over 340,000 reports. Of these 117,000 were from the US. Overwhelmingly these are sent in by email in the prescribed form ready for incorporation into the database. The use of paper forms is rapidly declining, also they are always acceptable. All of the 90ish years of data are now online at the website, except for very new data still under review. Even these are on the site as 'unevaluated' observations to clue observers to the behavior of their favorite stars. The Internet has slashed the cost and time and effort to handle requests for information and data. Virtually all the boilerplate information about AAVSO is on the website, as are all of the starcharts, lightcurve programs, notices and bulletins, and announcements of meetings. Mattei demonstrated this by the numbers. In the Oct-Sep frame AAVSO HQ received about 240 paper requests for assistance. The website fielded in the same time over 100,000 requests. This is not hits or visits, but fetching of information by download. She announced a fantastic meeting for next spring, one which many AAAers will definitely want to attend. It's on 2000 April 13-16 at the Marshall Space Flight Center, Huntsville, Alabama. The meeting includes a crash course for home astronomers on high- energy physics. This is meant for those following -- or more and more observing -- objects emitting in wavebands outside the optical zone. It ties in with the proposed gamma-ray burst alarm system and the growing need for home astronomers to understand what happens beyond the red and violet ends of the spectrum. One obvious set of folk who may really push to attend this classroom tuition is that from the Recent Astronomy Seminar.
89 Herculis --------- Dr John Percy gave two papers on different stars. The more interesting was on 89 Herculis, near the Cerbei Caput asterism in the summer and early fall sky. It is a binocular and small scope star with a 65 day period with profile indicative of pulsations. This short period makes it a favorite for home astronomers for its continuous activity at every observation. The star is a supergiant leaving the redgiant phase and crossing the upper edge of the HR diagram. The pulsations could in time regularize into those of a Cepheid. But superimposed on this period is a 282 day slow oscillation, recently discovered from archival data from AAVSO and the Fairborn Observatory in Arizona. This long period also suggests pulsation, as does separate radial velocity measurements. However, over the decades, the periods are increasing whereas in the usual case of a supergiant the period decreases. The model for 89 Her postulates severe mass loss while it was still a redgiant that offset the tendency for a shortening of the period. That is, angular momentum was shedded far more than normally. In addition the star has strong radiation in the infrared bands, a mark of fluorescence between optical radiation and dust. One possibility is that the lost material persists in a stellar ring.
American home astronomy --------------------- Thomas WIlliams gave some history of the early years of the AAVSO and some insight to how home astronomy centers developed in the United States. In the early years of the 20th century many efforts were mounted to build an omnibus national coalition of home astronomers comparable to the British Astronomical Association in England. America still looked to England as a role model for many phases of its life well into the 20th century. This never caught on. What happened is that there arose several phaenomenon-&-object orgs, like AAVSO for variable stars, which submerged the 'sections' or 'divisions' in the general national groups. Where the BAA has a variable star section, the US has AAVSO. Over the decades since AAVSO's founding in 1911 other such P&O groups were established. Among them are American Meteor Society, Association of Lunar & Planetary Observers, and International Occultation Timing Association. In this country national comprehensive groups withered or were stillborn. The only major exception is a strong and influential regional union of astronomers in the place where astronomy doesn't belong. That's the Amateur Astronomers Association in New York. The best the United States accomplished for a national home astronomy group is the Astronomical League. This is a confederation of local astronomy clubs. Its main function is to provide sundry services out of reach of the individual clubs for their small size and means. Williams based his paper on visits to several astronomy centers across the US, including to the Association in December of 1998.
solar spectroscope ---------------- Gerald Dyck described his homemade spectroscope. He based it on a stock Edmund reflection grating. The collimators are old binocular objective lenses and the slit is the classical double razorblade. He tested out the optical arrangement by manoeuvering the parts, mounted on wood blocks like chessmen, on a large sheet of paper. When he got everything lined up right he traced the locations on the paper and cut his chassis from it. He uses it only for the Sun being that everything else in the sky is far too dim. Not even the Full Moon or Venus give clear spectra. He tried photographing the spectra with mixed success. The pictures have grotesque banding and gaps in the continuum. This is an artifact of the trilaminar emulsion of color film, for which there is no cheap and easy remedy. He may turn to black-&-white pictures later.
CCD shutter errors ---------------- Dr Ronald Zissell brought up a hidden source of error in short exposure CCD photometry. The shutter may open in a pattern that lets photons from some parts of the field pass thru longer than from other parts. The differential accumulation of photons from various parts of the field must be accounted for in photometric assessments. He used a bivalve shutter, hinged at one end of its diameter, placed on the viewgraph projector to illustrate the problem. The stars far from the hinge are exposed longer than those near the hinge. The effect is due to the mechanical movement of the shutter blades. He showed other shutter patterns, including iris, multivane, and curtain. All have their own exposure function over the field. To obtain a correction factor one must take short exposures of a white field, as if doing a flatfield exposure. Then map out the photon count over the whole field. Exploit symmetry to fill in missing points. The actual photon count then has to be adjusted according to this map.
conclusion -------- Saturday's banquet was at the hotel followed by an award ceremony for accomplished AAVSO members. There was no special talk like that on Friday night. This dinner delivered the only substantial downer of the convention. One or maybe two batches of the food were undercooked or almost raw. I had to push away my vegetarian pasta; it was, well, tough and grassy. The delegate to my left waved away her chicken whitemeat plate. Sheraton offered replacements, of course. In balance, the Thursday reception, the Saturday lunch, and all the breakfasts in the hotel were tasty and filling. The breakfast buffet was well stocked with second helpings allowed. The convention wound down on Sunday morning with many delegates heading for a tour of Cape Cod. Dan and Alice already left for home on Saturday morning. I packed up, ate breakfast, and got a taxi back to the bus station. From thee it was the six hour ride to the Port of Authority with arrival just after local sunset.