Monday, January 31, 2005
Monday, January 31, 2005
A double-decker assemblage arrived to serve as the 8:07 train perhaps to compensate for the zero-decker that arrived on Friday (or didn’t!). Perhaps also with so many parking spaces in Boston still buried under tons of snow this larger train is here to accommodate an increased passenger load. Yet more likely it is nothing more than a scheduling aberration where too many double-deckers wound up in Worcester Sunday night.
On the south side of this cabin the morning’s sun streams into a giant window to my right, perhaps a reason for so many empty three-seaters on this side of the train. At any rate, here I have chosen space over glare.
Initial feeble attempts at blocking the sun have been marginal. For a time I resist the temptation to rig up a better shade. But after enough blinding light from both the sun and passing snow cover I can no longer resist another attempt. This time I’m tying a scarf to my bright red windbreaker at its wrist and hoisting the whole side of the coat across the window using an overhead luggage rack as a pulley. The coat lays flat against the glass, its armless sleeve comically pointing straight out to the side.
It’s odd, ugly and almost vulgar. But it works.
Mark leans into my seat just as I realize how he is about to remind not to leave my rail pass in the seatback ahead. Instead of the usual six or seven he tells me that we are only five cars today so this is not a full-sized double-decker by the conventional definition.
“Nice window shade…” is Mark’s parting comment – to which I responded how I’ve had lots of practice with window shades – and until today, most of it a failure, which I do not say.
Arriving at downtown Natick there is no sunshine beating against my newly shaded window, seeing how the rails runs here through a deep channel 20 feet below the natural grade. This gives me a chance make further adjustments without distracting other passengers beyond reason.
In view of so many paragraphs devoted to this double-decker and my improvised window shade, perhaps I am simply happy sit aboard a far more comfortable and roomy train this morning. Or maybe I have no earth-shaking insights snarling to get onto this page.
Through the woods east of Natick and under the bright sun blazing at Wellesley College I notice a modest dome shielding its modest cassegrain telescope, and I struggle for the name of the guy who runs the public observing sessions there – or used to five years ago.
Fundamentally, a telescope dome is not an architectural element and instead mostly functions to protect the instrument from daylight and foul weather. Sometimes also, when observing from suburbia, a dome will help to block stray light from neighboring civilization. Few things exist so entirely for a practical reason as a big and elegant telescope dome.
Yet in a twist of irony, it turns out that a dome is not the best shape and except as a daytime weather shield and sunshade, a dome causes more problems than it is worth.
Earthbound astronomy requires steady air. All sorts of things conspire to move air around, and if mixed at different temperatures the air acts like a weak lens – a very -bad- lens. When the lensing effect is minimal we call this ‘good seeing.’ When the effect is noteworthy, we pack it in for the night.
In the evening as a telescope dome cools, it acts a bit like a chimney. Heat from the day needs to leave the building. This keeps the dome warmer than the surrounding night – heating the air right along the skin of its structure. As this air rises it gains velocity creating a vacuum in its wake. This vacuum creates the chimney effect as it pulls and accelerates air following behind. Because of the curved shape of the dome, rising air follows the curve to where it collides with air rising from all around the dome. This collision then mixes warmer air with surrounding cooler air, which then slowly rises as spreading cloud of turbulent and unstable air right above the dome – right through the telescope’s field of view.
It’s a minor effect. Yet after spending thousands or even millions of dollars to build an optical instrument, it is certainly worth addressing. Nowadays we still call these enclosures ‘domes’ yet more often than not they are straight-up cylinders keeping rising air from converging overhead, and sometimes the whole top of the observatory simply rolls off the building’s foundation to remove as much of the structural heat as possible.
Somehow in the gentle starts and stops of this train we have already reached the rails at Wellesley Farms. For a moment I gaze upon the small pond just east of the train station’s tiny parking lot. I do not recognize the pond for all the ice and snow and brilliant sunlight rushing through leafless trees. It could be a small meadow for all I can tell directly.
Underway again, we make our way from the Farms, slowly turning to the north. For a time the sun is almost directly behind us – and as usual I am disoriented for a moment while the celestial map in my head argues how this shouldn’t be the case – if we are indeed headed for Boston.
Soon, almost without any sense of turning we are again facing mostly east again with the southeast sun once more sneaking through the gaps of my impromptu window shade.
I cannot be sure, but it’s reasonable to guess that crossing over the Charles River brings us into Newton. Something about the tips of very expensive homes looming through the wooden hilltop high to our right offers that clue. Wellesley is an expensive town with a fair number of larger homes in its own right, but much of Newton is in another league where expensive homes are built within eyesight of the rails – which must say something about those homes tucked far from sight. I also happen to know that Newton is a small city where some zones are like all other small cities – encompassing lower rent districts and places where ordinary people can buy an ordinary newspaper or a cup of coffee still described and sold as ‘coffee.’ But the pedestrian Newton is the exception more than the rule, and except for a lack of taller buildings it very much has a ‘city feeling’ – a rich city feeling.
The gentle ride of the train into Allston is not merely the consequence of our luxurious carriage suspension system at work – we are actually rolling slowly and have been doing so for quite some time. At this pace we will be ten minutes late, but so far I’ve heard no announcements – in fact, this morning I’ve heard no announcements at all.
With lots of time to ponder my commute this morning, we crawl into the open mouth of the Back Bay Tunnel. I can say one thing about the graffiti on the backs buildings in this area. The words and symbols are routinely over-painted by agents of the building’s ownership and then repainted by the graffiti maestros and gang-taggers in an unending tussle. And yet, in the process, at least the brickwork stays freshly coated!
