Tuesday, February 27, 2007

20070303 - Eclipse planning

On 03 March 2007, Moon will be in eclipse as it rises at 5:43pm. I'll be at Carl Schurz Park around the 86th St. entrance. I'm sure they will be many others. Eyes, binoculars, and telescopes should be plentiful. Ideally, the weather will be on its best to let us enjoy the show.

img credit: snip from larger illustration NASA's Eclipse Page managed by Fred Espenak

This eclipse is unusual because the Moon itself eclipses, or occults, this bright star during totality. 59 Leonis is magnitude 4.98, a challenge for the urban observer. This occultation will most likely require optics to observe the actual moments of ingress and egress. Perhaps a test for the eagle eye.

The following Eclipse time table & illustrations were prepared and distributed by John Pazmino.
Thanks, John!

17:43 moonrise 00 81 before sunset on March 3rd
17:44 totality begins 01 81 right after moonrise
17:48 sunset 02 82 moon in totality
18:21 mid totality 06 87
18:34 59 Leo ingress 15 95 2:00 o'clock on limb
18:48 nautical twilight 11 90 full night for NYC
18:57 totality end 13 92
19:11 59 Leo egress 15 95 2:00 o'clock on limb
20:12 partl phase ends 26 105 umbra leaves Moon
20:32 paenumbra leaves 29 110 ~20 min after umbra
00:17 Moon transit 55 180 on March 4th

image of eclipsed Moon & 59 Leonis prior to occultation

Illustration shows location of 59 Leonis a few minutes prior to ingress of occultation.
image of partially eclipsed Moon & 59 Leonis egressed from occultationIllustration shows location of 59 Leonis a few minutes past egress from occultation. Typically this is a challange when stars emerge from the bright limb of Moon but under this circumstance, a chance to see the star "blink" on should improve considerably.

Sunday, February 25, 2007

20070224 - filled with pleasure

Session name: 20070224.1710

After a hiatus from observing that included a getaway to Bermuda, I returned to TotL. When an observing session at TotL is not part of the week, the interval between sessions always feels like ages. Having been about two weeks, I had that feeling to shrug off.

I arrived earlier than usual with the Teleport. Sun was still up and people were still walking around. This scope grabs attention and that was my intent. I wanted to share sidewalk astronomy and this session turned out to be a real delight. Many passersby stopped during setup and after the cool down and throughout the night. Even before Charlie arrived around 8:30 at least two ~ three dozen people and families stopped. One gal summed it up when she asked us rhetorically if we were the astronomers, following it up saying that everybody knows you guys.

A small crowd assembled as we looked for Venus while Sun was still up. It takes two or three people to look up, squint, and point toward the sky. This is enough of a core to build a crowd. Actually the extended hand with the hang ten hand sign is marking off 21°. Only one other person and myself saw Venus when the Sun was above the trees, almost all saw her when Sun dropped below the tree line.

Early I showed off Moon & Venus. When Sun set and the brighter stars appeared on a darkening sky, I showed Saturn rising above the trees in the northeast. For most of the adults and children this is their first time looking in the scope.

Saturn looked very good with tonight's condition. At 180x, a lot of detail was observed including A, B, & C-rings, Cassini Division, banding across the planet, and the southern polar hood. What caught my attention was the shadow on the leading side of the planet (right in our reflector flipped fov). It isn't long after opposition which occurred on 10 Feb and the shadow is already noticeable.

Daniel, the young intern, stopped by my second time meeting him. He arrived when I was looking at M81 and M82 (SEDS M81 & M82) through my favorite eyepiece - Tele Vue Nagler 17mm T4 - with the Teleport. He wasn't impressed at all, lifting and dropping his shoulders with a "Eh". Daniel is a dark sky observer but he doesn't have his scope here.

I made a round with doubles and multiples spanning the sky from Aries to Leo when offering a survey of the sky to a young couple Fatima & Jesse. Nice group of folk. I gave them a standard tour of different object types that included a ringed planet, a bright, winter nebula, open clusters naked eye and in the scope and more.

Charlie, Kin, and Mark would arrive later on. This sessions celebrity came in the form of J. D. A. Wiseman, an author was passing by and remarked on the scope. J.D.A. doesn't escape what is common practice for Team TotL to remember the various people that pass. Just like Michelle the Librarian, Greg the Painter/Met Guard, Mark the Literary Agent, Hawaiian George, and the many, many others, J. D. A. became the Cambridge Mathematician. A volley of banter revealed he earned his Mathematics degree from Cambridge and he mentioned that he sat in on a few of Dr. Steven Hawking lectures. (And Mark has a story with Brian Greene, both of them are affiliated with Columbia Univ.)

The best line of the night without a doubt was: I suggest you drop the precious. I'd love to tell you the story about the line, but I'm afraid the humor is reserved for "...you had to be there."

Before we packed up Charlie and I observed a few objects in the spring sky. I hopped over to M3 which looked really good at 75x. At first glance this globular cluster is"crunchy" and when the eye relaxes on the object, stars partially resolve above the cluster and along the periphery. Its brightest concentration, wanting to call it center is actually off center. Charlie and I described the brightness profile slightly differently.

I made half hearted attempts which I abandoned on M65 & M66 and NGC2903, three galaxies in Leo. I didn't check charts and thought I could hop right on them but when I reached the fields and scanned the area I didn't see anything pop out. I ended moving on to the galaxy M94 in Canes Venatici. M94 was was very easy because its surface brightness is bright. In terms of size, the galaxy appeared as a smaller "fuzzy" than the globular M3 but lacked the stellar resolution except its nucleus.

One of my favorite monthly events occurred with Time's Up making their monthly Central Park midnight ride, led by Richard. Got admit it that I love when these folks stop by. And like the crescent moon events - it's a weather permitting meeting.

Time passed so quickly with the late Fall, Winter and early Spring skies passing over us. Team TotL and the many others that I met over the course of the session shared peeks and stories and questions and answers. It was pretty busy most of the night and I didn't log any notes of the session until now. I dropped by Charlie's blog to his post of this session for some reminders. But nights like these don't fade from memory so easy.

Some of the hyperlinks lead to Kiminori Ikebe's website. A terrific inventory of astrosketch and information of a number of DSOs. Well organized and the Japanese website is more up-to-date and interactive.

Other links lead to SEDS, another fantastic resource for the interested person.

Saturday, February 10, 2007

20070209 - Clouded out & Colded

Session name: 20070209.2050

Snippet of Cartes du Ciel screen. Blue was observed; gray was not)

Arrived at TotL with a positive forecast but poor transparency. It went downhill then an improvement sometime around midnight. My scope was already packed. I showed Saturn to the passersby by hat was all. It wasn't worth the effort to look for anything. Occasionally, Kin, Charlie, & myself would step up to Charlie's tripod mounted bins. The screen grab is a snippet from Cartes du Ciel and shows what we saw of Saturn and its moons in the eyepiece at 100x. (Blue - yes; gray - no) The size appears to be close to what we observed. Anything larger was pretty soft.

On 10 Feb, Saturn is in opposition; a syzygy of Sun, Earth, and Saturn. I prefer observing Saturn from another location in Earth's orbit. Saturn's disk casts a shadow on the rings which this enhances the 'sphericity' of the planet. Sometimes I feel like I can see the shadow extend into space. A pretty cool optical or mental trick.

By midnight we all agreed we were men enough having withstood the cold, stomped our feet to the pavement one last time. It would be a short time later when each of us would arrive to a place not so hellish.

Friday, February 09, 2007

20070208: Galactic starhop down memory lane

Session name: 20070208.2030
Handheld Binos: Fujinon 7x50 FMTR-SX, fov 7.5°
Tripod-mounted Binos: Takahashi Fluorite APO 22x60 Binoculars, fov - 2.1°

The highlight of this session was observing M81 in the Tak bins from Central Park. I looked for M82 in the same field but had different results. As M81 resolved as a milky oval at the apex of a small equilateral triangle in the eyepiece, a moment of disbelief passed. I traveled back to a time when I began observing in Central Park. Traveled to a place we call TPO.

I first met team TotL back in October 2003 and began observing with them from Turtle Pond Observatory. Our squatters' right dubbed the spot TPO. I had just gotten the Tak 4" refractor, replacing the Coulter CT100 and Tele Vue Ranger as my primary scope. This was the time when I began in earnestness to learn the sky. I was seeing most objects for my first time. I was meeting many of the dog owners that I know today. I am grateful to Ben, Charlie, Curtis, Rich, and others that assembled there, sharing their scopes, knowledge and experience. It was all learning for me at that time.

One evening during this dawn of amateur astronomy, after a couple of failed attempts to starhop to M81, I prepared a chart to deliberately find this galaxy. I didn't know about surface brightness and contrast. Atlases showed magnitude 7 & magnitude 8.5 thinking these should be easy. Instead I recognized small triangles, kites, and diamonds that fit within circles the size of a 2° field of view. A trail of these were drawn from Dubhe. This gomsa post describes the night when M81 & M82 appeared to Debbie and me for the first time. Debbie & Sammy, dog owner and dog, that I haven't seen in years. Together we shared the excitement of bagging the galaxies, even with a 6.7d waxing Moon, from Central Park. A feat not many have, let alone in small scopes.

Fast forward to today, I have seen some 30+ galaxies from here, all but half a dozen or so, needing the 10". This evening, I look at 23- & 29 UMa drawing an imaginary, flat triangle to the east where sometimes I'll see 24 UMa. I land the bins, look into the eyepiece seeing a 1° right triangle, which has a mag 7.2 star along the long leg. I look southeasterly across beyond the apex to find M81. I struggled for m82 spending some time in the eyepiece to dark adapt. I suspected an area that averted vision registered a reaction but I couldn't confidently place it in the field of view. I am confident that on a more transparent night that M82 could be seen in these 2.6" optics.

These actions are almost second nature now; effortlessly, not taking more than a minute. Many of the objects I observe frequently are at or nearby familiar landmarks in the sky. Like a deli at the street corner or the bookstore in the middle of the block, the street with the 3rd building down that has the blue door, I learned many city landmarks in the sky. With thousands of objects in the sky, while discovery remains an opportunity, I traverse the sky and find new pathways, comforted in knowing where I am, so I can return.

2003 used to feel so close, close as a glance over my shoulder. But now in 2007, it seems more distant. From my beginnings, Saturn has moved from the belly of Gemini, passing M44, and now located in the sky making a smaller version of the Square of Pegasus with Regulus and other stars of the Sickle. Jupiter, now is Ophiuchus, the thirteenth zodiac, takes about 12 years to orbit Sun. Now 3+ years into observing, Jupiter has moved than a quarter of the way around since he was in Leo.


Image credit 2005 Digital Sky LLC, obtained from Wikipedia

Labels: , ,

Monday, February 05, 2007

20070204 - Risings and settings through the window

Here are some shots of objects seen setting and rising on Sunday evening. Displayed in shooting order.

Venus shines brilliantly above the rooftop while Mercury is observed setting between the valley of two buildings. This shot taken through the window.

Color shot taken after Mercury set behind the building. This shot taken through the window.

A shot of the moon through a window that faces manhattan-east with camera aimed to the northeast. Moon rises, occulted by church spire. The reflected image's brightness is attenuated beautifully to make out the mare and other lunar features.

Here is Orion rises, camera is looking out the same manhattan-east window, but now points to celestial south east.

Labels: ,

Sunday, February 04, 2007

20070203 - better skies for naked eye

Session name: 20060703.1920
Equipment: Teleport TP-10 & Fujinon 7 x 50 FMTR-SX

The cab transported the scope & I up to Mariner's Gate. This is the usual entrance for Top of the Lawn observing sessions and it has a small grade hill right at the start. In fact, to the south just on the other side of the playground is the highest point in Central Park, Summit Rock. The summit, at 141 ft./43.0m, is 1 ft/0.30m higher than Vista Rock which sits on the far side of Turtle Pond at the south end of the Great Lawn. (Climbing up Belvedere Castle, one reaches the highest point in the park.) Summit Rock's great elevation bleeds along this edge of the park, a small ascent I sort of dread.

Walking up the grade I look through the naked trees seeing the Winter Hexagon and Orion blatantly in the sky. It does look clear. Bundled in layers of clothing, my jacket is tucked in my backpack to avoid overheating. Catching my eye to the northeast is the rising Moon maybe 2½° ~ 3° in altitude. A striking buttery yellow, a honey moon hue - she is large! The branches and limbs can't conceal this girl -- she's much too large. I lost sight of her as the foreground buildings occult her view and I arrive at TotL.

I set up the scope and put the fan on to get it cooling off. I looked around feeling at home. Last month there weren't many nights I got out so I was looking forward to this one. While waiting for scope time, I spent time using a pair of my favorite instruments: mine eyes.

The February 2 essay of the book, 365 Starry Nights, Chet Raymo refers to a small illustration that shows a section of sky looking south. He asks, "Can you find Orion on the drawing above?" I think for most of us we'd find it with no problem. When one easily gets their bearings, not only is Orion apparent but one can see a trail of constellations: Lepus, Columba, Puppis, Canis Major, Monoceros, Canis Minor, and a dense river of dots showing the path of the Milky Way. Chet describes how both dogs have a pair of stars of unequal brightness and Canis Major's is more widely separated. The lines created by the pairs are almost perpendicular.

Canis Minor's pair are Procyon & Gomeisa. Canis Major has the brightest evening star Sirius coupled with Mirzam, Arabic for "announcer". Canis Major's stars are brighter than its counterpart in Canis Minor.

Look further south in Canis Major two stars that are part of the big dog's hind quarters, Wezen and Adhara. Adhara, the brighter one, is west of the fainter Wezen. Low in declination these stars don't rise that high in altitude. Jumping west, I look for Furud, zeta Canis Major, a magnitude 3 star. The low elevation and the approaching gegenschein radiating from the CitiGroup building both present challenges to Columba. It takes a clear, transparent sky to pick these stars up, ranging from magnitudes 2.65 to 4.37. Magnitude 4+ is difficult at low altitudes approaching and beyond celestial south. The gorgeous Manhattan skyline and a dark night sky collide.

The scope had cooled down and maybe a dozen people, a blend of friends and first timers, passed over the course of this session. Moon was shown only to a few as it was low, stressing the dobsonian to a seemingly horizontal recline. A survey of the different objects consisted of:
  • Solar System: Saturn
  • Open Cluster: M35
  • Planetary Nebula: NGC2932, Eskimo Nebula
  • Bright Nebula: M42 & M43
  • Multiple Star: Trapezium
I didn't look so hard as the seeing was poor. Saturn was still soft at 100x but large enough for the people to recognize and admire. Personally, I preferred the naked eye skywatching. I recall looking to the west seeing Aries hanging perpendicular in the sky, dancing past the Pleiades & Hyades, into the sky describes above. Higher up approaching zenith, Gemini attracts attention. I'm waiting patiently for the clear, transparent night when M35 appears to glint for my naked eye.

And it was cold! The MONY clock flashed 24°/-5°C but it felt much, much colder than that when the wind gusted. Throughout the night, Charlie & I listened to the nearby tree crying of the cold: wheeee, wheee, wheee. It wasn't difficult to decide to pack the scope around 11~ish when the clouds came in.

Labels: , ,