Tuesday, May 29, 2007

20070528 - Manhattanhenge

Session name: 20070528.1900

Manhattanhenge 2007 sequenceSunset observed from 34th & Park Ave.

The turnout this year was nothing like last year. Charlie & I shared our curb with a couple who came in from New Jersey. Across the avenue to our west, other photographers and sightseers watched the sun emerge and set in a hazy sky. Rather than filter the solar disk, the haze just smeared the light with a brighter center. The sun was weak when observed through a solar filter.

A shot of Venus setting into the foreground rooftop, the Empire State Building in Memorial Day colors.

A montage of close-ups.

Grand Central Station Mercury Clock

Hung out for a while at 34th & Park to watch Mercury cross the street. Determined that it wouldn't show up until 9:20pm so Charlie & I decided to move on. Found Mercury earlier than suspected. When I arrived at West 57th St., I pulled out the 7x50 bins to see Mercury as a ruddy-colored point still more than 5 degrees in altitude.

Monday, May 28, 2007

Update: Manhattanhenge on 28 May 2007

20070528.2017 - Sunset for Manhattanhenge

(photo from last year, read about it here)

There is correspondence bouncing around Team TotL that Manhattanhenge May 2007 is tonight. Charlie referenced the Manhattan-henge article on the Hayden Planetarium website. I referenced a message from their email newsletter service star-struck. This article provides the following sunset dates for Manhattan-henge around these dates:
  • May 28 at 8:10 PM
  • July 11 at 8:27 PM
It appears that most will observe the event tonight, especially since I heard this date more than once from others. I'll most likely join others at 34th & Park Ave. Arriving by 8pm will be adequate to watch the sun set into New Jersey, requiring at least 15 minutes before sunset. Sunset is the time when the sun's upper limb descends below the horizon. That is the Sun has disappeared from our view. To observe the Manhattanhange, one begins watching prior to sunset.

It has been a lot of fun in the past and the energy created by the interested persons is uplifting. In spite of its small scale, it is one of those events that brings New Yorkers together in harmony. Where else can one see when a traffic light change for red and a hundred or more people rush the center line flashing away?

Lastly, listen to the caution that many will voice: Don't look at the Sun directly as it is harmful and dangerous to one's eyesight.

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Want to know more about sunset?
U.S. Naval Observatory
- Rise, Set, and Twilight Definitions

- Complete Sun and Moon Data for One Day calculator

- Sunset

Fox Lane High School


Sunday, May 27, 2007

20060526 - A couple of hours out on the Solar System

Session name: 20060526.1835

The weather forecast for the evening of this session was not too positive but at the time I decided to go it was partially clear. At times, I could see the light grow bright and shadows sharpened on the buildings outside of our windows. That was encouraging enough that I intended to scout Vista Rock for the Manhattanhenge sunset. As I left the house with the Bin backpack over my shoulder, I turned to my wife saying I'd return just after sunset.

Knowing that there was some time to kill, I sat on a park bench to leisurely sketch the Moon. A father and his two sons sat to my left. One asked if I was looking at the Moon and, naturally, I invited them to the eyepiece. Small gasps but I wondered if they could really appreciate what they saw. In broad daylight, even with blue skies, the contrast is low and experience has shown that one needs to adapt in the eyepiece for some time. Theirs were quick glances but they did remark of big craters. (The mare I suspect.)

I use the Moleskine pocket plain reporter notebook (wanting to return to the standard portrait binding) to capture what I see. My notebooks are filled with lunar disks smudged with graphite to show the mare. I continue to practice for scale, relative location and obvious features. Hopefully the day will come that I get the courage to sketch specific lunar features. Nothing special but it does help to stir my memory. In fact Clavius, on the left, is not entirely accurate. The interior craters are not properly scaled or positioned, but the shadowing along the northeastern wall and the small, dark shadow south of Clavius emboldened the lines of the wall and impressed a curvature or 3d to the observation. Similarly, Sinus Iridum held fascination with the western wall rising into the sunlight while the foothills below were still in shadow. Without an atmosphere, the stark difference between night and day on the Moon must be stunning.

While on the bench, I thought of others snapping photos with their camera phones. Since the Nikon CP995 was on hand, snapped this at the eyepiece. I am impressed by what others can get using this method. I just don't have a steady hand for this.

I blew off my wristwatch alarm that alerted me to 20 minutes until sunset. Instead, I moved over to the east of TotL where the view on the western horizon is low. The horizon rises and falls between 5° ~ 10° along azimuth 270° ~ 300°. A familiar observer, Ken Taurian, stopped by and shared sights of the Moon and Venus with passersby. We looked for Mercury and spotted it when the sky darkened at civil twilight and the clouds let some sky through. Carol & Dog "E" came by at this time. We saw Mercury through the handhelds as well as the tripod mounted Taks but couldn't see the planet naked eye. Nobody was impressed by any color or shape from the planet.

Kin arrived by skateboard by after dark. Mike, one of the birders, also stopped by. It was too late for them to see Mercury but Venus, Saturn, and Moon were obvious. Clouds shrouded the Moon in a thin veil and then moved off. The Tak bins delivered very pleasing views when the sky conditions allowed. The 1/2° moon frames nicely in the 2.1° field of view. It wasn't much longer that the clouds would win out. I remembered what I told my wife so I packed the bag and left the company of Ken, Kin, Mike and the park passersby to return home for a movie and popcorn with the family.

Thursday, May 24, 2007

2007 May 30 - Manhattanhenge notification

Manhattanhenge occurs May 30th, beginning at 8:10 p.m. It happens a second time later in the year on 13 July at 8:20 p.m. Any street that looks across town to the western horizon works. In the past, I have tried 34th St. & 57th St. This year I am considering Vista Rock Summit Rock, one of the highest elevations in Central Park and overlooks W83rd St.

In a star-struck message from AMNH, Neil deGrasse Tyson corrects a misnomer "Manhattan Solstice":

Note that last year, an article in the New York Times identified this annual event as the "Manhattan Solstice". A term that has achieved some currency since then. But of course, the word "solstice" translates from the Latin solstitium, meaning "stopped sun," in reference to the winter and summer solstices where the Sun's daily arc across the sky reaches its extreme southerly and northerly limits. Manhattanhenge comes about because the Sun's arc has *not* yet reached these limits, and is on route to them, as we catch a brief glimpse of the setting Sun along the canyons of our narrow streets."
Read the 2002 City of Stars essay. As with most celestial events there is a ramp up time and ramp down to the day of the event, so watch the sunsets on the preceding and succeeding days as the Sun slowly creeps northward along the western horizon.

Monday, May 21, 2007

20070520 - 1st International Sidewalk Astronomers Night in NYC

Session name: 20070520.1500

Sunday was a tossed salad weather day. Early on it was partly cloudy with blue skies, quite a change from yesterday's weather of completely overcast skies with rain at times. ISAN was canceled for rain in NYC. Today, however, seemed to be a day of redemption. I braved the clouds and forecasts with the Tak102 nearby Turtle Pond Observatory (TPO) at the south end of the lawn.

Despite the gloomy darkness and threatening clouds, many people stopped to ask what was special today. I relayed to them the efforts of Donna Smith trying to mobilize a thousand amateur astronomers around the world to the street to share the night sky through our optics with the public on Saturday, 19 May. Since yesterday was a no-go, I was giving today a shot to show off the solar system. Through out the day from 3:00 to about 9:30, I would say a hundred or so folks stopped by. Early in the session not all had a chance to see anything but still stuck around asking questions.

I arrived mid afternoon wanting to share sights of the Sun. Sunspot 956 was clearly evident. Often times we had for the clouds to yield to the Sun. Actually, I think the clouds help the pedestrian grasp what they are looking at. For many, I inform them that the entire white disk they see is the Sun. With a black field of view, it is very easy for one to miss the fact that sun is not the little black dots on the white circle, rather the entire white circle is the Sun & the little black dots are a grouping of sunspots. (magnification ~ 26x; field of view ~ 2°). With the clouds passing before the Sun it provides something familiar the observer can relate to. Also, I suggest that folks look through the viewing window to see safely observe the Sun with no magnification. once again seeing a round disk and clouds passing over now become a familiar, known sight that when they look in the eyepiece, an equivalent to Eureka! moment occurs. I can't help but a grow a smile when this occurs.

Within an hour after I arrived black clouds advanced from the west. In a short amount of time it began to rain. Grabbed my daughter's pink Hello Kitty picnic blanket and wrapped the scope. I found shelter nearby at the Delacorte Theatre where many others stood beneath a large overhang. There I met Bruce & his son, a lab man at a local college, where I received a lesson in general optics and microscopes while waiting out the rain. When returning to TPO, Bruce carried my tripod. Thank you, sir!

On this second toss, Venus and the crescent Moon were the objects of our desire. Tom came with his Fujinon 16x70mm which were homed on Venus. I bounced back and forth between the two, though mostly on the crescent.
The wet sidewalks and shallow puddles from the rain dried rather quickly. The lawn before us was now empty, people returned slowly but fewer in number.
Ben would arrive about this time and he concentrated on Mercury. He pointed it out above the western treetops to the assembling crowd where it was a difficult naked eye object but rather easy in the bins.

Venus exhibited a phase very close to what is shown above. This photo of Venus was snapped through a Tele Vue Ranger & a 20mm Plossl eyepiece. Clearly the slight gibbous hump is evident as Venus is nearing its last quarter phase. In the field I pu;; out the Palm to show Ian's Venus montage that shows phase and size over time as she orbits the Sun inside of Earth's orbit.

This was one of the larger groups that came through, maybe a dozen young adults in one group with a few other unrelated couples. The guy with the black backpack, hand to his pocket mentioned that one of his RSS feeds (the name escapes me) mentioned that sidewalk astronomers were taking to the streets. His gal at the eyepiece was about to observe Saturn and Titan. Many were thrilled with seeing the ringed planet amazed that one could see it so recognizable, so clear.

This is an illustration snipped from Starry Night Pro, showing the arrangements of the 4 moons. To the keen eye, three other moons could be seen. For the Tak in the park, 4 moons is par for the course, and occasionally Iapetus, a fifth moon when circumstances are right.

I am glad that I made it out to share with teh public and hope that the others in the City were able to get to the street. Two AAA observers, Bruce & Rik, were planning to setup by the American Museum of Natural History while Derek was to be headed downtown to Union Square. Rich was setting up with others in Brooklyn. I'll be checking the gomsa board to see if any reports are posted.

Wednesday, May 09, 2007

20070508 - Left my game home

Session name: 20070508.2000

I read albireo's blog with a degree of envy of how he effortlessly hopped & skipped across the sky. He describes the galaxies he observed along the way. Oh! and he popped in a filter to observe some nebulae. Not once but twice. M57 & M97.

Me. I struggled this session. Sometimes it's like that, busted. Need a re-boot. Didier stopped by with his dog. She sat in the ball field on the other side of the fence while we looked to the stars of Corvus and Virgo. Maybe it was this time that albireo was teasing the galactic nuclei from his skies but with the 4" Tak refractor that's a bit of a pull from here. Consulting Karkoschka's Atlas I decided for both of us that NGC 4361 was the target. That was the beginning of the frustration which mounted progressively in a short period of time. To say the least, I found the field but neither could detect the object. Another struggle with M57 as the Lyre cleared the trees this cluster nebula was way too low. Most objects I planned to observe didn't yield easily. The dog tired of waiting and casually approached Didier giving him the glance. Didier turned around and mentioned they had to leave.

People passed by and I showed them Saturn. How could I miss? The regulars passed, stopped and said hello.

It wasn't difficult to decide to pack at midnight. Stan the photographer & his dog Gigi stuck around after the packing completed. A bright meteor fell from the sky, lasting about 20° with a sputtering tail. It was really bright causing a real drawn out Wowwww. Sluggish as it was I thought Stan would see it when he turned around, but it was that kind of night. While talking about photography the sprinklers came on exactly at midnight. Charlie had been watching for these in past sessions but we lucked out. Tonight, not. We got wet from the spray but continued to speak. As we walked out of the park, I pulled my Palm out to show him the photos I have saved from Andrew, Astromick, and Vern.

Knowing these things pass, I'll have soon forgotten the struggle, only remembering that fireball that rained down the sky while showing off the bloggers' photos.

2007 May 19 - Int'l Sidewalk Astronomy Night

I plan to be at the southeast corner of the Great Lawn, Central Park setup by 8pm EDT. Later around 10:00pm, I'll move eastward towards Delacorte Theater, about 50 yards, for a better angle to observe Jupiter rising above the trees in our northeast..

Objects I intend to show will concentrate mostly on the Solar System and, if possible, will show a little diversity with Doubles, Open Clusters, and Globular Clusters.

Sunset occurs at 8:09pm EDT. I anticipate waning, gibbous Venus and waxing, crescent Moon to be the early showcase in the constellation Gemini, standing in the western sky. A 2° field of view eyepiece should capture both and also provide enough magnification to see Venus' phase. Naked eye I am sure it will be splendid sight. From the southeastern corner of the Great Lawn, Mercury will be visible at 15° altitude descending with Taurus. Mercury will appear as small round dot under high magnification, at 6" (arc seconds) in size, distinct from a stellar point. If one can visualize the size of the Jovian Moons, then Mercury will be slightly larger. Not much longer after sunset that Saturn pops from a twilight sky leading Leo's head. Regulus, alpha star of Leo, will be recognized to the left of Saturn, more easterly. Even at this hour and a magnification say 50x ~ 60x, everyone will see the rings and moons of Saturn. Higher magnification and increased contrast will provide greater size and more detail to the observer.

While waiting for Jupiter to rise, there may be time to offer some celestial diversity with open clusters like M35 in Gemini or M44 in Cancer. When Jupiter does rise the Great Red Spot will be near the center line of the planet and 3 moons will be visible. Europa, Ganymede, Callisto will be seen with Jupiter while Io will have to egress from two events: an occultation and followed by an eclipse.

A pretty double star that exhibits color is nearby iota Cancri (STF1268 magnitudes: 4.13/5.99), north-northeast of M44. Speaking of doubles, Polaris, alpha Ursa Majoris, is a fun object. First, to point out where our North Star can be found and which you may discover many do not know. With adequate magnification, Polaris will reveal its much fainter secondary star. Though no color, this pair exhibits a great range in magnitudes - 2.10/9.10 - with Polaris (WDS STF93). Lastly, there is Mizar & Alcor, a naked eye double in the tail of Ursa Major, or more familiar to pedestrians as the handle in The Big Dipper. Can you see the lost sister hiding naked eye? Then throw a scope at the pair to observe that Mizar has a come 14" ( seconds) separated. Compare that with Mizar at 12' (minutes). Sidus Ludovicianum will be spotted as a fainter star between Mizar & Alcor.

Staying with deep sky sky objects that are relatively bright, a couple of the bright Messier globular clusters are easy to find and may be suitable for the scope. M13 is easily found in the Keystone of Hercules and M3 in Canes Venatici is nearby and slightly fainter.

I expect all to have a good time with a good dose of fascination and good cheer. Typical for our sidewalk astronomy nights in Central Park.