GLOBE AT NIGHT 2008 TELCON ------------------------ John Pazmino NYSkies Astronomy Inc www.nyskies.org firstname.lastname@example.org 2008 February 25 initial 2008 March 10 current
Introduction ---------- The Night Sky Network (NSN) of NASA-JPL and Astronomical Society of the Pacific (ASP) from time to time offer telephone conferences with its affiliates to better discuss various topics in public outreach for astronomy. The one on Tuesday 5 February 2008 featured 'light pollution' or, as it's known in the City 'luminous graffiti'. This is the GLOBE at Night program (GaN). The session, starting at 21:00 EST, was hosted by Vivian White of NSN and Connie Walker & Chuck Bueter of GaN. I represented NYSkies at this telcon. Here I present both a summary of the conversation with NSN and GaN and additional comments that missed the dialog.
GLOBE at Night ------------ GLOBE at Night (GaN) is a project sponsored by National Optical Astronomy Observatory (NOAO), Tucson AZ, to enhance public awareness of light pollution. NOAO operates Kitt Peak National Observatory and other astronomy facilities, and has an immediate concern for the loss of the night sky thru luminous graffiti. Set up in 2006, it offers assistance and materials to anyone, mostly home astronomers, for promoting sound lighting practices to reduce luminous graffiti. Its theme is not only for astronomy but for the wider scope of environmental and social benefit. The 2008 round is the first for NYSkies. It just did not know about GaN before then.
The telcon -------- About 30 callers participated in this telcon from Maine to Hawaii. The rollcall was a bit rapid and I lost count. i don't recall any from outside the US, altho GaN is a worldwide effort. Attending the phone call itself was a simple matter of dialing a certain 800-number and giving the conference agent a passcode and name. Unlike a regular conference call, which is set up between specific phones, this session could be entered by callers from any phone. Probably the freecall is valid only within the United States, closing off overseas callers. To keep crosstalk and banter of some 30 people in check, the session was mostly a one-sided chat, like listening to radio, between the hosts. The responding microphone for the listeners was muted. After the host talk, the phone line was opened for listener dialog. One person at a time was let into the open line, as queued by a key press on his phone. At the end of the session, at about 22:20, we were released to hang up.
Preparation --------- NSN deposited in its website several files to download and have in hand for the telcon. The main one was a PPT file of 44 slides, which could be printed onto transparency sheets for a group presentation. One idea was to have the telcon around a speaker phone with the slides projected, like at a club meeting. Listeners could also gather around a computer and view the slideshow as a digital presentation. I printed the slides on paper and binded the set into a report cover. I did this because for this first telcon I was at a phone far from my home computer. The host chat went thru the PPT, well enough written and illustrated for self-instruction, with a few sidelights and comments. The hosts first explained luminous graffiti, a simple homemade demonstration of it, and feasible remedies, GaN sky assessment methods, and reporting procedure. The essence of the latter two are to match the eye's view of Orion and with one of a set of graduated charts. The charts are numbers for the approximate magnitude of stars plotted in them. For example, on Manhattan on the nominal clear dark night -- away from nearby lights shining on the observer's face -- transparency is 4th magnitude. This would match closely chart #4 for the corresponding number of Orion stars.
Photometer -------- GaN in 2007 devised a photometer to measure sky illumination, in magnitude/arcsec2, that was given to clubs by random drawing. NYSkies missed getting one, but it is not crucial for GaN participation. This device is called a 'Sky quality meter'. It is a handheld device, like a calculette, with a photometer sensor on top and a single 'start' button. It is aimed at the clear open sky with no obstruction or reflections in its field. It accumulates photons and registers their mag/sec2 value. This is, with other sundry info, recorded on a report form. Because lay people, and few home astronomers, work with mag/sec2, the units in the readout are called 'squims', from the initials for 'Sky quality meter'. Without this device or other similar photometer I have no idea what the sky illumination is for the City, at least in the parts I frequent. GaN can correlate the photometer readings to threshold magnitude. A back of envelope calc gives for a 4.0 transparency a sky illumination of 18.5 mag/sec2.
Public activity ------------- The ideal use of GaN materials is to get the public, those outside the astronomy world, involved with measuring sky conditions and turning in reports. While this is one path to a greater public awareness of the luminous graffiti situation, it can be tough to implement in some settings. At least, for sure among the listeners, the clubs can and will use the GaN methods during their public starviewing sessions. There was discussion about giving instruction to school officials and students on light pollution. Again, this is an ideal situation due to the packed schedule for education in the school semesters. In some parts of the country unreviewed and unapproved outside intrusion is not taken too kindly, given some of the recent 'science' topics that wormed their way into the classroom. There is also the burocratic conditions in schools that frown on external collecting of information from or by students and teachers. I came onto this situation in the last few years with the NYC Science & Engineering Fair. Altho operated with NYC Department of Education sponsorship, there is a rigorous review and evaluation of requests to use surveys and questionaries as part of a student's science project. A science project attempted without this approval, as must be proved by appropriate paperwork!, is expelled from the Fair. Regardless of how the lay person may take part in GaN, he can be tutored in luminous graffiti at club activities like starviewings, meetings, special shows. A few listeners were from planetaria and could bring luminous graffiti into their presentations under the dome.
NYSkies operation --------------- NYSkies is skipping a general public enrollment in the GaN, keeping to its own crew and supervised visitors. It is real chancy to expect proper reporting from untended lay people, who will treat GaN litterature as merely a curious handout. When, if ever, a lay report is received, there is no way to perform a sanity and purity check on the information. The numbers turned in will be unverifiable. NYSkies will give the GaN project to its colleague group Top of the Lawn (TOTL). This team of telescopists sets up in Central Park, in the middle of Manhattan, on most clear evenings for public starviewing. Its crew will assess Orion each evening for GaN. This procedure should give consistent data from a single known location for the whole two-week GaN run by more or less the same observers. It also takes measurements from what some astronomers consider among the very worst places to stargaze from. In addition, TOTL will ask visitors, who stop at the telescopes, to inspect Orion and pick out a matching GaN chart. This report is turned in separately from the main TOTL one. In this way, we know that the lay person gets a proper instruction and obtains results of credible value. For NYSkies members who are not in Central Park, GaN measurements will be made, on an occasion, from where ever they happen to be in the City on each evening. for instance, I may inspect Orion from my house when I arrive home from work after nightfall.
Luminous graffiti --------------- The term 'light pollution' seems to escape proper meaning for the community enclosing astronomy. It can be taken to mean 'minor, lesser, pollution', compared to 'heavy pollution'. The term also does not emphasize the effect of skyward dumping of excess illumination. In the late 1990s, as part of the impending millennium crossing, astronomers in New York City adopted the term 'luminous graffiti', alluding to the marring and defacing of the sky by spraying photons into it. The City at that time was coming off of an icky time when regular graffiti -- sprayed paint on walls -- was rampant. The City's response was mixed, from new bans on selling spray paint to minors to incorporating graffiti as a quality-of-life violation. We eventually rid the grosser graffiti from public places, like subway cars and highway structures. Mitigation of luminous graffiti is a collateral theme in PlaNYC, the manifesto to green the City for a projected one or more million growth in residents. People in the City in the turn of century period were intensely familiar with the societal degradation evidenced by painted graffiti. Transferring this theme to the sky, 'luminous graffiti' was a natural concept for us. in working with developers and planners, as well as managers of existing properties, 'luminous graffiti' is more graphic a description of the potential damage from photon dumping into the sky.
Up and side spray --------------- One of the classic examples of a star-hostile lamp is one that spreads its beams out and up. The slide show had examples of these lamps. In a four-story town the effect of these lamps is, ahem, disastrous for stargazing. Light beams fly up and over the skyline. In New York there are two tempering factors almost unique here. First, out and up beams don't get into the sky so easily. They are intercepted by towers around them. Only beams sent into the zenith reach the stars. The other is that the towers are residences or night businesses. Their occupants at night can -- and do! -- complain loudly about disturbance from upward beams. In an instance in December 2007 I attended a conference on energy conservation in a Lower Manhattan skyscraper 40 floors above the street. In evening the audience went to a reception overlooking the street. There, front and center, on the street a quarter=K away was a glaring floodiamp! Its beams filled the reception room to the point of casting shadows WITH THE ROOM LIGHTS ON. This was meeting was convened by utility delegates and state & local officials! They noted that lamp (we ALL saw it). They vowed to 'look into the matter'. On the very next evening, at an other, unrelated, lecture in the same skyscraper, The lamp was GONE.
Reflected light ------------- One of the topics in the dialog of the GaN telcon was reflected light. Photons sent downward are bounced back up and can trash the sky. This is specially true with shielded lamps, that direct their output to the ground, supplying more photons to reflect.. This problem is often missed out of orthodox light pollution education, In fact, in the very PPT slides showing shielded lamps, the down beams just disappear when they meet the ground! It would seem that the problem of reflected light is more or less the same thruout the US. The landscape is pretty uniform everywhere with grass, dirt, brick, wood, stone. Where the potentially greatest amount of down lighting may be installed, for general street lighting, the southern tier of the country may suffer more than the northern. Northern states tend to pave roads with asphalt, a black or dark gray material. Its low albedo reflects back a small fraction of street lamp output. Southern states generally pave their roads with concrete because their hotter climate softens or melts asphalt. Concrete is white or light gray. even after soiling by traffic. Its higher albedo reflects upward significantly more light from street lamps. Similar reasoning applies to other large planes for vehicle traffic like parking lots drive-in theaters. It may be impossible to remedy the light pollution from reflected light. The texture and substance of the ground is dictated by factors well outside the province of outdoor lighting.
Snowcover ------- A collateral reflective situation comes when it snows, common in the northern states. With snowcover, even a single centimeter deep, the ground becomes a highly reflective uniform indefinitely large plane. The amount of light reflected upward off of snow can call off critical observing. The result is that nights otherwise well suited for stargazing, being clear and steady, are lost during snowcover periods. Note well that the GaN round is smack in the middle of the northern snow season! I would suspect that sky darkness will be skewed to the worser side by snowcover in reports from the frostbite regions. The GaN paper report form asks about snowcover but the webpage report form does not.
Why Orion? -------- I'm guessing Orion was picked as the target for GaN partly from the intent to get the lay person to participate. 'Orion' is a familiar word, in common use for business names, In the Noertheast, it is the name of two distinct electric power companies! Funny thing is that one firm says its name as 'O-ree-yonn'. The other says 'oh-RIGH-yonn'. In New York it's the model name of certain street buses! I see from time to time an Orion bus working the M42 route on Manhattan. As a group of stars, it has many bright stars to make it easily recognizable with personal validation of most lay people. Even under grossly bright skies, at least a couple of its stars are visible to get a positive transparency statement. From the worldwide effort of GaN, Orion straddles the celestial equator, making it visible from all parts of the globe. Depending on the hour of the observation, Orion may be in mid heaven, high in southwest, or low in west. The sky darkness is generally a function of altitude (worse near the horizon) and locally a function of direction (in the glow of a nearby truck stop). While GaN can suss out the alt-azm of Orion from the time of observation, it can not apply any indigenous intelligence to an apparently poor sky assessment.
Alternatives? ------------ Some astronomers in the City, while discussing the GaN project, suggested other groups. It turns out that almost all require detailed familiarity with the sky and, therefore, may preclude a role by the public. The favorite alternative is Ursa Minor, with a range of stars from 2nd to 5th magnitude. The argument is that Ursa Minor is always in a fixed location in the sky and is identifiable once north is determined. Ursa Minor is either low in the sky or out of sight from low north latitudes to all of the southern latitudes. That kills a global coverage. It also is not an obvious figure of stars. apart from Polaris and Kochab, you really have to contort the imagination to make out a 'dipper' shape, assuming you do see the fainter stars. An other alternative was the Big Dipper, an obvious pattern of stars. In northern winter it is in northeast, too low or hidden by skyline. It also lacks a graduated mix of stars for magnitude assessment. How about taking measurements always in the zenith? For us in the north latitudes, Auriga is overhead and has a mix of stars, including the winter Milky Way. A lay person can be instructed to examine the are around the brightest star overhead in evening, Capella. Again there's the latitude factor and a time factor. Late at night Auriga drifts into the northwest, leaving the zenith occupied by the poorly stellated regions of Lynx, Leo Minor, western Ursa Major. All in all, It seems that we stick with Orion for now.
February window ------------- The GaN request is that NSN affiliates do sky assessments from February 25 thru March 8, when the Moon is out of the evening sky or is small. It wasn't certain if only ONE datapoint was wanted in this period for a given location but it seems that as many as practical are useful. This would span a variety of local weather conditions and help smooth out anomalous observations because, say, there's a conflagration in the next hood on one particular night. TOTL in Central Park is on duty pretty much on every clear night. NYSkies will have it do runs every time it's in the Park for the whole two-week period. An additional run was suggested for the lunar eclipse on February 20th. NYSkies and TOTL should observe before, during, and after totality. The sky during the eclipse was generally clear, but there remained a thin high cirrus gauze that tempered transparency over the City to only 3rd magnitude.
Aurora watch? ----------- In spite of the overall lower activity on the Sun nowadays, there were recently a few strong solar eruptions that caused northern lights over various states. There can plausibly be major aurorae during the GaN observing period. With more astronomers outdoors specially for making the Orion assessments, perhaps they could inspect the sky for aurorae. This would collect a concentration of reports for a two-week span from a variety of geomagnetic locations around the world. Inspection for aurora should be conducted within the astronomy circle, without trying to involve the public. The observing techniques are a bit peculiar and require intimate knowledge of the local sky. More over, in many locations there can be unusual temporary ground- produced illuminations in the sky that are easily confused with northern lights.
Reports from lay folk ------------------- From my workaday career, I can compare GLOBE at Night to other efforts to collect data from the general public. I have friends, associates, colleagues who track birds, tree leafing, insects, snowfall, water quality, and many more items. In many cases they try to get the public involved to gain more reports and greater coverage by time or region. The results are mixed. It is plain naive to expect diligence from a lay person not already part of the instant interest. Bird sightings can be gathered from members of a nature club but not reliably from the casual audience at its meetings. River pH readings can be obtained from members of a riverkeeper club but not from casual swimmers along the shore. It could be futile to ensure that the pH of water samples was correctly and properly measured. The lay person may not understand or follow the instructions given to him. Did the person really wash the collection bottle with distilled water? Did he wait the required three hours to let particulates settle out first? Did he read the first or next band on the pH stripe? Did he pick the water from a clear shore point, not from the paint factory's outfall? Things like this can foul up beyond all recovery (That's one meaning of 'FUBAR'.) the documented condition of the river. The results of these data collections can work themselfs into decision and policy processes, like enacting a new water quality rule or building a new bird flyway station. I tell you, these results, as obtained from people out of the circuit of the pertinent profession, can be severely challenged in the social forum. GLOBE at Night data, and its online maps, can become just as much a football if not structured and interpreted with competent supervision. I'm told, and I'll have to check this during the TOTL runs, that the online reporting is anonymous with no way to trace the entry to a particular observer. If so, an errant entry may indeed be fouled up beyond all recovery and probably has to be left in place. In the case of a lay report, it is hardly likely that the person will later review his entry for goofs, like mistyping, wrong lat-lon, date rollover at midnight, and so on. These errors can occur for astronomers, too, as I've seen for occultation, variable star, and meteor shower observing. I hope that there's some means of reviewing the entries, which an astronomer would be more attentive to do, and correcting them,
Low-vision observers ------------------ One intriguing statement made during the host dialog was that older eyes may not see 5th to 7th magnitude stars. With the general adveteration of the astronomy population, specially in clubs, there has been an overburden of depressed sky transparency from precisa mente this cause. It is likely that reported sky deterioration over decades is a mix of real increase of luminous graffiti (and other air pollution) and declining vision of the astronomy population. On top of this is the real consideration that eyesight varies enormously among any given group due to a portion of low-vision people. To some extent the astronomy population suffers a 'natural selection' as low-vision people are weeded out by failing to see what orthodox stargazing expects of them. They turn to other pursuits, leaving astronomy behind. Among 'indoor' astronomers, low-vision people are present in about the same portion is in the general population. If anything, their ratio is higher since the 1990s with the assistance of ADA. ADA governs places of public accommodation, those where public astronomy is offered. In the past low-vision people were discouraged from attending certain astronomy functions due to poor lighting and confusing landscape. Many functions require driving by car to the location, a task often beyond the low-vision person. Today signs, lighting (helping to remove luminous graffiti!), color/shape distinction, demarcated slopes are far better suited for taking part in astronomy activity.
What is measured? --------------- GLOBE at Night wants to chronicle luminous graffiti by assessing sky transparency in the direction of Orion. The collected record is the number of the standard Orion chart the best matches the sky view. Does this measure actually document light pollution. It seems that there is a hidden assumption that any defect of measure from the top transparency, chart #6 or #7, is pura mente caused by luminous graffiti. Seasoned observers know that defects of transparency are due to many causes, not just light pollution. I mentioned one above about defects from low-vision or aging astronomers. Because GaN is still new, it is on a learning curve, trying to find a valid means of separating light pollution effects from others. Maybe the Orion chart method will be replaced in the future? Any influence on the value captured for transparency I and experienced observers can think of works to decrease the transparency, never to increase it. Factors like lack of dark apation, general fatigue, medical side effects, industrial air pollution, soiled eyeglasses or contact lenses all force the reading to a lower value, fewer stars, brighter sky. Likely the biggest problem is to get the astronomer to acquire dark adaption first before looking at Orion. Stepping outside from a lighted room and looking up will slash the reading to an artificially poor value. That's what happens so routinely when the public is released outdoors for starviewing after an indoor talk. It remarks how few stars the can see, yet the sky looks dark. Only after many minutes does the eye shift to night-vision. tt would be reckless, for example, to discuss GLOBE at Night to an indoor audience and then send it outside to immediately take readings. Other examples of depressed readings come from an observer having a stressful workday, having a domestic fight, taking a sedative medicine, seeing a highway collision, escaping a store shootout, learning adverse family news, having a hygiene accident, and on and on. All of these influences worsen the reading and there are no obvious and casual ones that can better it. The bottom line is that GaN data could be wrongfully offered as proof of light pollution status in a given district. Such assertion could be severely contested in a policy or decision proceding.
International Year of Astronomy ----------------------------- 2009 is the International Year of Astronomy (IYA), the 400th anniversary of Galileo's first observations with the telescope. Many astronomy centers are planning special celebrations then. NYSkies is working with other clubs for IYA at the 2009 Astronomical League convention, coming to Long Island in summer of 2009. Likely the Allies in Space show for 2009 will highlight the IYA and space exploration. NSN and GaN are preparing some special activities for IYA, as yet in gestation. Details will be announced in their websites.
Potential conflict? ----------------- This telcon was set for Super Tuesday! Some 20 states ran primaries or caucuses for the presidential candidates, each until early night in local time! As far as I can recall, no one specificly noted this potential conflict during the telcon. Apparently the listeners already went to the polls or opted out. There was no conflict with the Super Bowl tickertape parade because that took place in mid day. I, with a million other cityfolk, were still high from that show when the telcon began.
Astronomy Day ----------- Many clubs are gearing up for their annual Astronomy Day shows. I explained that NYSkies does not do Astronomy Day. It takes part in Earth Day. Earth Day in the City is a gala celebration attracting hundreds of thousands of visitors. Earth Day is typicly a street fair taking up a few hundred meters of street or an acre or so of park. Astronomers before the founding of NYSkies had a spot at Earth Day. Now the go in with NYSkies as the New York City astronomy delegation at the fair. Attendance varies with the weather. We had, as I can remember, only two rainouts when there were only 10,000 or so visitors. (The exhibition is held rain or shine.) The largest attendances were at the fairs in Madison Av and in Water St. Each drew a full one million spectators. The boon of Earth Day is that large corporations and agencies pay for the all of the arrangements: booths, music, performers, handouts, decorations, publicity, advertising. NYSkies pays a modest fee for its booth, builds a display for it, prints its own handouts, and handles other other out-of-pocket costs. For only a couple hundred dollars, NYSkies gets into a show that would otherwise set it back millions of dollars and involve immense burocratic manipulations. In a very honest sense, astronomy in the City is lavishly supported by the likes of JPMorgan-Chase, myspace.com, Elle, NYS MTA, Toyota, Con Edison, MotherJones, Burt's Bees, Grand Central partnership, NYS ERDA, Transit Center, US EPA, Clean Air NYC, NYC DEP. These are only the major ones, as noted on the sponsors page of the 2007 Earth Day souvenir book. All the exhibitors, including NYSkies, are described in its pages. The exhibitor shows up, assembles its display, and fields the avalanche of visitors. As long as it's not raining (the fair is always in April), the people come. Every one loves a fair. For the astronomy community, Earth Day is the perfect setting to show Earth as a planet, to show off the Sun with solar telescope (solar energy), discuss luminous graffiti (hard to save the planet if you can't see the other planets), and all that. This year of 2008 Earth Day is next to Grand Central Terminal on April 18-19 in a tent city. Inside the depot there are earth and space pictures projected on the columns. NYSkies gives luminous graffiti litterature, of its own design, to other exhibitors. Because the fair is at Grand Central Terminal, NYSkies has handouts to illustrate the astronomy points of interest inside the building. There's a LOT more than just the Sky Ceiling!
Light pollution reward -------------------- Transit Center, noted as an earth day patron, runs for the City the 'light pollution reward' program. An enrollee by positively abating luminous graffiti gets a monetary congratulation of as much as $110 per month! This is NOT voodoo money. It's the crinkly stuff you can spend for light pollution outreach work or pistachio malteds. By now most astronomers in New York are enrolled, bringing home varying amounts each month, but averaging $76. That along in a single month covers your astronomy club dues and a magazine subscription. One of the NYSkies handouts at North East Astronomy Forum (NEAF) tells how the show could be FREE if you enrolled in this program at the previous NEAF. the annual accumulation of monthly rewards can easily pay all of your NEAF expenses and have left a pile of cash for astronomy gumbo.
Land use review ------------- In the City, when a major project is proposed, a public review process kicks in. The proposal is presented to the people for comment, review, critique. The developer must make good faith effort to effectively solicit, receive, and consider the public's input about his project. What is the 'public' depends on the project. For the new World Trade Center the review was conducted by, litterally, the entire world, by delegates from just about any country you can think of. The main meetings were held in the Javits Center with an audience of some 10.000 delegates. More typicly, the project is presented in its vicinity in a public venue, like an auditorium or gallery. Representatives of the project discuss the plans with the visitors and collect comments. Displays, models, videos, posters round out the presentation. NYSkies attends many of these reviews to offer guidance concerning luminous graffiti, in additional to the usual bread-&-butter issues. Major projects tend to be stupendous on the scale of most of America. The Hudson Yards project plans for 500,000m2 of commercial floorage, about 5,000 residences, and towers up to 300m height. One universal criticism was that no tower may challenge the nearby Empire State Building. It's a fullsize mid Western town.
Civic integration --------------- NYSkies gave each of the Hudson Yards reps flyers about luminous graffiti. Most reps then pointed out on their model how they are already looking after outdoor lighting! They also took the materials for study back at their offices. Similar dialog was exchanged, before NYSkies was founded, with the Grand Central Partnership, Times Square redevelopment, Riverside South development, and several housing estate managements. In all cases, outdoor night lighting was given due consideration, resulting in greatly reduced (but not always eliminated) luminous graffiti. In a very real sense, NYSkies, from its peculiar status in New York City, can have its thumbprint on building entire new towns! We do got lots of company for our efforts. Civic, environmental, social, business groups are involved. They argue for their interests, like parks, transit, sewer treatment, traffic circulation, sports salons, arts and culture halls, school seats, waterfront greenways, and more. From this scene in the City, it has long been the astronomer's function to become integrated with hs encompassing society. The ivory tower mindset plain doesn't work and can be, in the case of light pollution, glatt hazardous to his profession. It is an imperative -- Jovis manu menteque! -- that astronomers take proactive part in civic affairs to make their existence known and knowable, to present their concerns, to steer their town from obnoxious growth to one of harmony with the planet. This must be a continuous process, not just an Astronomy Day exhibit.
Stargazing as 'astronomy' ----------------------- It is prevalent to equate 'home astronomy' with 'stargazing' in the orthodox litterature. You're not really a home astronomer UNLESS AND UNTIL you engage in stargazing. In New York with its chaotic weather -- with February 2008 being one hell of a good example! -- NYSkies and astronomers before NYSkies never stressed stargazing as the road to home astronomy. Far too many stargazing sessions are called off for bad weather, a situation that rapidly quenches even the most fiery of initial enthusiasm. No stargazing, no home astronomy. You may think of the many lunar eclipse sessions that were cancelled in the afternoon of 2008 February 20, sending many eager skywatchers into other busyness for the evening. What happened in the Northeast? The sky CLEARED UP during the partial phases and totality was observed in generally cloud-free skies! Probably a lot of public folk, marking an eclipse watch on their calendar, were royally annoyed.
Other urban factors ----------------- An other major impediment to stargazing is the lack of a casually available viewing site, the 'backyard', in many parts of the City. Recall that overwhelmingly, city astronomers live in flats in towers. The rooftop is often closed off or filled with obstructions. The lawns and paths are hemmed in by towers, exposing only the zenith. On Manhattan there is Central Park (notable the site for Top of the Lawn), Carl Schurz Park, Battery Park, a few others. Even there, the traffic is too dense and distracting for serious observing. Instantly you set up your apparatus, a crowd collects and you end up showing celestial sights to it. Not a bad favor, of course, but it takes away from your own observing efforts. Stargazing can be an important element of an astronomy career but it can not be the ultimate or dominant feature in the City. One of the immense value of the monthly NYC Events column is its huge number of indoor astronomy activities, making up for the punctured chances for regulation stargazing.
Correlative factors ----------------- One slide for the telcon was a plot of sky darkness against population density near Tucson, Arizona. There was a loose concordance between density of residents and sky darkness, but there are several anomalies. One is a low sky darkness, high sky brightness, in the southeast part of town, surrounded by a density of less than 1,000/mile2. Just from this map it's impossible to understand this feature. Intelligence can come only from local familiarity with the town and perhaps an on-site visit. A possible cause of the bright sky is a highway rest station, the plots being close to road I-10. GaN could, in a higher level of operation, give such plots to the astronomy center of each town so it can check into such anomalies. The center would use local resources, like paper maps, aerial photos, GIS layering, personal visits to see what's going on. For New York City GaN would work with NYSkies.
Population density ---------------- The Tucson map did draw out a giggle from me. The density scale tops off at 24,142/mile2. There's no way a scale of values would purposely have such a step! The value is suspiciously a conversion from metric. Using the close approximation of 2-1/2 km2 to the mile2, I hazard that the original step is 10,000/km2. I compare this to the residential density on Manhattan. In the zone on Manhattan between Central Park and East River, the Upper East Side, the population density, the one used for municipal planning purposes, is, uh, 50,000/km2. It's easy to see why Manhattan had no choice but to exploit the third dimension. Towers in this district reach 150 to 200 meters in height. I did carefully note that this density is that for planning. It is taken from the US Census data. it's no secret that there are a lot of people in New York who opted out of the census, something like 1-1/2 million. This is quite the counted inhabitants of Phoenix, Arizona. The actual density of Upper East Side is more like 65,000/km2! This is handsomely evidenced by the crowding in the stores and streets and trains in this nabe.
GaN observations -------------- Here are the recorded chart matches from various sites in New York City during the GaN period of 2008 February 25 thru March 8. This is a dark Moon interval when celestial luminous graffiti is in ebb. Observations were taken with the procedures established by GaN. The main observing station was the Top of the Lawn site in Central Park. This location is sometimes offered as the worst place to stargaze from. Other sites were used occasionally, mainly near astronomers's residences. All hours are Eastern Standard time. Daylight Savings Time kicks in on March 9th, in the morning following the final night of the GaN period. ------------------------------------------------ Date Hour Chart Location Comments ------ ---- ----- ----------------- -------- Feb 25 19h 3 56 St & B'way MH Feb 25 20h 3 Central Park MH by lay person Feb 25 21h 4 Central Park MH Feb 25 21h 3 Central Park MH by lay person Feb 26 --- N/A whole City cloudy, no observations Feb 27 --- N/A whole City cloudy, no observations Feb 28 20h 3 56 St & B'way MH Feb 28 21h 4 Central Park MH Feb 28 20h 4 Gelfands Hill BK Feb 29 --- N/A whole City snowing, no observation Mar 1 21h 3 Tompkinsville SI Mar 2 19h 4 Gelfands Hill BK Mar 3 18h 2 Gelfands Hill BK mostly cloudy Mar 4 --- N/A whole City raining, no observations Mar 5 20h 2 Gelfands Hill BK mostly cloudy Mar 6 23h 3 Gelfands Hlll BK Orion low in west Mar 7 --- N/A whole City raining, no observation Mar 8 --- N/A whole City raining, no observation ---------------------------------------------------------------
Conclusion -------- The telcon was recorded and a transcript will be put into the NSN website. If any one objected at the start of the meeting, he was allowed to disconnect. I didn't hear any one take that action. On the whole the telcon was orderly, mature, informative, useful, and encouraging. The host talk was well presented with good comment about the PPT slides. Time ran low for the Q&A. Listeners were waved down after only a couple minutes. In fact, the 60-minute planned time for the call went to 80 minutes.