Looking Up

The place local astronomers have dubbed Lakeside is not one of western Utah’s more beautiful sites. I’ve never hiked a desert I didn’t like, but Lakeside is toward the bottom on the scenic scale. Near the Air Force bombing range in Tooele County, in a bowl formation amid low sere mountains, the site features a sloping earthen dike about six feet high, oceans of fine white dust, and not a tree or large bush.

Underfoot, a clayey surface glistens in little hollows edged by mud cracks; it’s as if the pits were damp from rain, but they’re dry — I dug my sneaker in to make sure. Green shotgun shells are scattered on the ground. Through stretches that are bare of the dispirited brown scrub grass, vehicle tracks form a network of scars. A few patches of broken porcelain and glass lie on the dike’s crust, evidence of target practice.

[The scope set up during a trip to Lakeside. Photo by Joe Bauman]

Yet a lovely transformation sets in after sunset. The evening is overcast and clouds are lighting up crimson where they line above the lumpy mountaintops to the southwest. To the east, brilliant Jupiter climbs higher over rounded peaks. A breeze kicks up.

A crescent moon is buried within cloud banks and then reappears briefly as it sinks nearly due west. A car hurtles by on the paved road a mile away heading toward I-80. Five miles farther off, winking orange lights outline semi-trucks on the freeway that glide like ships in the darkness.

I’m forced to postpone aligning the telescope for an hour or two because the North Star has disappeared inside a monster cloud bank. But the clouds continue to thin as the night grows darker, and eventually I get it lined up with true north.

By midnight the moon is gone and most of the clouds have been erased.
The true beauty of this site stands forth. The Milky Way arches overhead, not as bright as it would be in a really dark spot, but a filmy wonder anyhow. As the night progresses, the Pleiades rise and assume a dominant position above all, while Orion slides upward not far behind. The air is clear and still by now.

Starlight alone would let you walk around without a flashlight, though the night’s a little lighter because of the wide low glow from Salt Lake City and the smaller splotch on the opposite horizon marking Wendover, Nev.

Through the night the Big Dipper slowly rotates as the stars revolve around Polaris. At last it seems to stand nearly on end, so that its stew of celestial treats threatens to pour out of the ladle’s bowl and onto the handle.

Tracking the stars exactly as they move has always been a frustrating challenge. A condition called periodic error faces astronomers, since no telescope’s gears are perfect. A minute defect in the gearing can jiggle the scope enough to blur an image during long exposures, and long exposures are needed for good astrophotos. The gears have myriads of imperfections.

Recently I purchased software that is supposed to correct the errors. During the previous trip to Lakeside I made hours of runs with the scope while the program mapped the flaws in the gearing. It reprogrammed the telescope’s computer, telling it where to goose the power a little and where to draw back some, so that the tracking would be more precise.

Finally on this night -— by now the morning of Tuesday, Sept. 14 — I have worked through most of the difficulties. Loaded with gear, the scope is in balance in three dimensions. I’ve fixed the collimation, which was off badly. Stars are focused in both my imaging camera and the smaller CCD camera used with the guider scope. After a lot of fiddling I managed to adjust the aggressiveness of the guiding software to match the needs of the telescope.

The pointing is off tonight; maybe that’s because I leaned on the tripod as I adjusted something; maybe my weight caused a tripod foot to sink a little deeper in the soft ground, affecting the accuracy. I can’t find several targets — relatively dim objects like Stephan’s Quintet, where four of five galaxies in the same field are interacting. They are too dim to show up in the nasty little finder scope. Removing the camera to find them with the main telescope would take too long on a night that is passing quickly; if I did that I’d have to refocus the camera when I replaced it, a laborious, time-consuming task.

Still, the face-on spiral galaxy M33 is so big and bright that it’s impossible to miss, even peering through the finder. I point the telescope at it and start the guider program.

The galaxy is relatively nearby so it seems vast to us. Actually its diameter is about 50,000 light-years, half that of the Milky Way’s; M-31, the great galaxy in Andromeda, is more than 220,000 light-years across. Even though the telescope is equipped with a focal reducer, only the very center of M33 can fit on the camera’s little detector. The small chain of stars near M33’s center stretches across most of the chip’s width.

M33 is about 2.9 million light-years away in the constellation Triangulum. According to NASA, M33 (also called NGC 598) may be a satellite of the monstrous Andromeda Galaxy. Andromeda, our own Milky Way, and M33 are the three major members of what’s termed the local group of galaxies.

In the fall of 2006 the largest known stellar black hole was detected in M33. Stellar black holes form when a huge star goes supernova and the remnants collapse; usually they are between three and ten times the mass of our sun. By contrast, supermassive black holes millions or billions of times the mass of our sun lurk in the central bulge of most galaxies studied so far. Oddly, M33 seems to be an exception: it does not sport a big bulge; if it has a black hole at the center, apparently it isn’t so super, at only 1,000 to 3,000 solar masses.

The stellar black hole weighs in at close to 16 times the sun’s mass. It collapsed into existence when one of a binary pair of stars went supernova. The remaining star, about 70 times the sun’s heft, is “among the most massive stars” known, write Jerome A. Orosz of San Diego State University and Jeffrey E. McClintock and Ramesh Narayan of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.(National Optical Astronomy Observatory/National Solar Observatory Newsletter, December 2007).

The new stellar black hole “is a beauty because it is the only known black hole that is eclipsed by its companion star,” they add. The huge star and the black hole continue to orbit together, the star eclipsing the black hole from Earth’s perspective. Every three days, ten hours and 48 minutes, X-rays spewing from the black hole’s torus halt abruptly as the star blocks them. The regular eclipses “have yielded the most accurate mass measurement that has been achieved for any black hole.”

I dare to set the exposure at 90 seconds, three times longer than my most successful previous images. The tracking holds up well and I don’t find that much drift is smearing the photos that accumulate in the laptop. I will be able to stack several views to make one longer exposure.

This weather isn’t as cold as a few nights before, and when I walk around as the camera works, I pass into spots that are warmer than others. I admire the stars and Milky Way.

Darkness runs out before I can take color images. But the luminosity exposures (astronomer talk for black and white pictures) look okay.

[The middle of galaxy M33, 2.9 million light-years away, imaged from Lakeside the morning of Sept. 14, 2010. This is a stack of 11 luminosity exposures, each taken at 90 seconds, for a total of 16 1/2 minutes. Photo by Joe Bauman]

In the early morning few stars are left; between the clouds, the blue heavens seem to possess granularity, as if this were a view taken with grainy color film.

I doze in the Jeep with a blanket over my head to keep the sun from my eyes. At 9 a.m. I launch into the hour-long task of packing up the gear. While I stow stuff two large pronghorn antelopes wander up within a few yards and stand watching. They appear interested in the telescope and tripod.

Driving home, I have an odd empty-headed sensation. The bright blue sky, brown mountains with their shoreline escarpments left by Lake Bonneville, freeway stretching ahead, myself, the planet — all seem part of a oneness.

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