Sunday, April 22, 2007

Oh this is scary ...

After a month of poor weather, we getting a streak of clear blue skies. Already two decent nights of observing and the forecast looks good for tonight and tomorrow. Wonder if I'll be drawn out tonight after our annual Cherry Blossom picnic with friends in the park.

With Moon waxing and advancing eastward there's not much time left to starhop for the Virgo-Coma galaxies. Otherwise, I am waiting for next month and the Spring sky will culminating by the time astronomical darkness sets in. From TotL observatory, that means passing through the manhattan-Gegenschein - not a good thing.

As Charlie & I parted last night, his last words were if it's clear then I'll be down. Funny enough as he said this Jupiter was on his way up. Still a little too late for curfew enforced observatory.

20070421 - Details of the 4 1/2 day crescent moon

Session name: 20070421.1730

After a day Moon advanced eastward in the sky, leaving Venus further behind. With the bold punch that Venus delivers, most people noticed her even in daylight. Noting the separation of Venus and Moon, figured it was a good time to calibrate my thumb-to-pinky angular distance. With arm outstretched, it was a *perfect* fit from tip to tip. I guessed 21° for my hand and Charlie said 22 ½° for his. Checking Planetarium for the Palm, the angular separation was 21°27'.

Between sharing veiws with the passersby, Charlie and I would get some eyepiece time with a young crescent still holding the old moon. In the scope, we observed Grimaldi, Aristarchus, Mare Frigoris, and Mare Humorum in the earthshine. Copernicus and Kepler were not as easy as I thought they could be. Of the two, Kepler may have been spotted with much less confidence in Copernicus; the same with the Lakes near Mare Orientale. I'm not certain but believe these to be libration features. I thought I could see them but Charlie mentioned that libration was favorable on the eastern limb. Lo and Behold! Mare Marginis & Mare Smythii were both very well turned over our limb becoming nearside. I noted crater Endymion and but didn't spot Mare Humboldtianum. Along Moon's southeastern limb I was unsure if I saw Mare Australe. With libration so favorable to the east, the lakes bordering Orientale could not have been seen.

Two sets of mountain, Montes Secchi & Montes Pyrenaeus drew the eye into the central region of the morning terminator, providing borders to Mare Fecunditatis and Mare Nectaris. A large, irregular-shaped crater, Gutenberg, is an interesting crab claw-shaped crater, its northeastern wall collapsed.

The floor of Mare Nectaris was fantastic in tonight's light. One could see rings of arcuate ridges possibly revealing the rings of the basin. This was my first time noticing this effect. I counted three rings of the ridge effect and lastly a crumbled eastern wall, the lunar Pyrenees Mountains, circumscribing them.

Two valleys in the central and southern regions couldn't escape our attention. Vallis Snellius & Vallis Rheita are unmistakable as large, wide valleys cutting a straight groove in the lunar landscape. The Sun's angle today provided reasonable relief. Yesterday's observation left and impression of a sharp cut into the terminator. Quite possibly this was Vallis Snellius in the terminator.

In the park, spring is here. Green grass carpets the field before us. Trees surround us on all sides. Pollen irritates my wife's sinus. Birds fly from tree to tree, red robins stand their ground. People walk, talk, and play. Charlie stands next to me. I look through the eyepiece at the grayish, whitish lifeless world of Moon. It is hard to imagine that there once was a time when Life did not exist on our planet. I wonder if it was color that give birth to Life?

Saturday, April 21, 2007

20070420 - A mix of galaxies with bright stuff

Session name: 20070420.1900

A wonderful session prepared with the finest ingredients: seasonable temperatures, clear skies, wonderful people, fraternity, and a fine scope.

Over the course of this session, it wouldn't be an exaggeration to say that 4 dozen people passed by and took peeks. Moon, Venus, and Saturn with his 4 moons were shown to all of the new passersby and regular visitors. Highlights included:

A beautiful crescent with a good dose of earthshine. Grimaldi and Oceanus Procellarum could easily be seen. A double star had egressed from a lunar occultation. When I noticed it, it couldn't have been greater than the 1° from the northern bright cusp. In the lunar morning sky Mare Crisium and crater Langrenus were the most blatant features in the north. Craters Snellius and Stevinus were west of and flanked by Petavuis and Furnerius in the central region.

Saturn was beautiful and drew many reactions from the observers but poor seeing prevented a higher power than 100x. (Later in the evening past 11:30pm the seeing improved considerably where we observed Saturn at 181x with some fine details of the rings and on the planet.

Venus burned brightly once Sun set and was only shown when requested. Earlier some had observed her while there was still daylight and lower contrast. Seeing was poor but with some effort the gibbous phase was discernible at 100x.

For some of the folks that stayed with us, like Daniel who left and returned, or Christian & Tim, I mixed it up a bit by showing brighter deep sky objects. In no particular order and at different times over the session, we put in the eyepiece open cluster - M35, globular clusters - M3 & M13, and nebula - M42.

With expectations set, I shared with Daniel the passerby and Didier the duo galaxies M81 & M82. This wasn't too easy for them but they got M81. Didier may have gotten M82. From his description, I believe he got it and wonder if he can appreciate that he learned how to identify a very faint fuzzy.

I admire Kiminori Ikebe's hand at sketching the deep sky objects. The opening picture is Ikebe-san's rendition of 3 galaxies: M81, M82, and NGC3077. In the field, we didn't see NGC3077 and M82 was just better than averted, tough with direct vision.

Charlie arrived after 11pm from the Columbia University outreach. Both of us looked at a number of galaxies, detecting them and describing them in terms of their location relative to the starfied, shapes, orientation, and brightness profiles. Personally, I think that is a lot of information to gather from these very difficult objects in the urban sky. Under darker skies the objects will be larger and finer detail can be observed. The list of galaxies we observed included M81/82, NGC2903 was suspected but not definitively seen, M94, M51/NGC5195, and M63. This was my first time seeing M106 from Central Park. The range was great from M94 being easy to moderate like M82 to difficult with M63. M106 was almost as difficult as M63, but with adapting in the eyepiece, we still were able to describe a lot of their features.

It's for finding angels

I arrived at TotL earlier than usual with the Teleport as sunset was still an hour away and darkness coming around 9pm. I came early to enjoy the weather and release a little cabin fever anxiety. The weather has been bad for a good spell. Setup for the Teleport was a snap.

I was gathering my things together while the scope cooled down. From behind a woman approached asking, "What's that for?"

"It's for finding angels, and one is here right now," I replied spontaneously.

A smile grew on Deanna's face. Her boy friend Curtis came up shortly afterward. I enjoyed chatting with them while the scope cooled down. Curtis picked out Venus with ease, pointing below Moon in the western sky. They were both fairly high up, later to set beautifully & brightly behind the blossoming trees and Pinetum.

During this time many people stopped to have a look. It didn't matter that scope needed cooling and alignment, and that seeing was poor, every enjoyed a view of the 3 1/2 day waxing crescent Moon. With effort one could make out that Venus was a waning gibbous, but better seeing would have made it more worthwhile.

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Saturday, April 14, 2007

getting a prespective on things

Wohba! post invites our attention to various scales of size and distance. If Eames version is one flavor of ice cream, Wohba! serves up tutti frutti, rocky road, and praline pecan.
Discovered from "astromick" Hyde's blog - a new favorite.

Wednesday, April 11, 2007

20070411 - Trying for Mare Orientale

Session name: 20070411.0345

snipped image of M. Orientale I woke to an alarm at 3AM and readied to go to Carl Schurz Park. I awoke The Wife and she mumbled how noisy I was. A short while later I arrived at the eastern horizon-friendly observatory on John Finley Walk where Moon had already risen. As I set up the scope I could hear more than the sound of silence. First to my ears were some waking robins, becoming a chorus when I started to pack after 5:30AM. A very low frequency rumbling from tires on the highway below me kept a cadence that I didn't count. My eyes wandered from the glass topped river - calm. And then I looked up beyond Moon & Jupiter.

Summer is nearly here. In terms of right ascension, we're only a few hours away. The Summer Triangle had risen entirely, Jupiter appeared to be in Ophiuchus, or may have been in that tiny area of sky on the ecliptic that belongs to Scorpio. Sagittarius was low in the southeastern sky, not yielding a hint that the heart of our Milky Galaxy lies within its borders. More northerly and much higher Vega held Lyra above any treetops. My first look at the whole summer sky this year.

It was Moon and western libration that brought me out this early. Typically, I don't observe a waning Moon since it rises at this wee hour and I'm in bed until it becomes the old crescent Moon which is within a day of New Moon. Today, it is the promise of seeing Mare Orientale. It has been a very elusive feature and favorable librations with an appropriate phase seem to be rare. I don't think we've had one in a long, long while.

When I turned the scope on the lunar disk, seeing was noticeably poor along the limb. I shot a bunch of photos and none were worthy. I could see the lava colored floors of Lacus Veris (Lakes of Spring) and Lacus Autumni (Lakes of Autumn), on the outskirts of Orientale basin. But I couldn't say I saw Mare Orientale or Montes Rook. I noted their locations and irregular shapes. Nearby great Grimaldi, a crater with a similar lava-colored floor, served as a landmark to return that part of the limb. As noted earlier, observing along the limb was like looking through unsettled water.

image credit: snipped screen grabbed from USGS Moon General Image Viewer

Monday, April 09, 2007

Blue sky, naked eye moon

On my way to work this morning, saw Moon nearly the same elevation as the roof tops of the southerly buildings lining 6th Ave. A beautiful clear, cerulean blue sky as a canvas. With foreground objects that included the tree twigs and the buildings, Moon looked larger than usual.

I noticed two brighter, grayish marks central to the waning gibbous. I stopped pulled out a piece of paper and srew a schematic of the features I could detect naked eye. The most noticeable were the two features just mentioned: Copernicus & Kepler; Aristarchus could be seen just above Kepler. Further along the top a brightening thick line partially crossed the disk. I suspected this to separate Mare Frigoris from Mare Imbrium.

The moon's western limb was brighter than the rest of the visible lunar disk and Grimaldi appeared to be nestled in the border around an 8:00 position. In towards the "center of the clock" from Grimaldi, two separate maria are discernible: Mare Nubium on the terminator side (east) and Mare Humorum was the western one. They appeared nearly equal in size. Above them the large, darkened floor of Oceanum Procellarum seemed to occupy most, but not all of the gibbous Moon. I suspected a thin whitish line encroaching from the east towards Copernicus. May have possibly seen the Apennines mountain range.

Crossing the street, Moon looked to be nearly centered over the avenue, that is manhattan-due-south . But Manhattan is rotated 30° so checked Planetarium for the Palm revealing its altitude/azimuth at 14°04'/208°43'.

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Sunday, April 01, 2007

Online Sky Map

Rastos de Luz notes a useful web-based astronomy app, SKY-MAP.ORG. Pair the free wifi at TotL with something like the Nokia N800, the sky and our resources are unlimited.